Bump version to 0.13.0

(cherry picked from commit d75d221540)

.github/workflows/code_coverage.yml

@@ -24,7 +24,7 @@ jobs:
       - name: Update toolchain
         run: rustup update
       - name: Test
-        run: cargo test --features all-keys,compiler,esplora,compact_filters --no-default-features
+        run: cargo test --features all-keys,compiler,esplora,ureq,compact_filters --no-default-features
                     
       - id: coverage
         name: Generate coverage

.github/workflows/cont_integration.yml

@@ -10,19 +10,23 @@ jobs:
     strategy:
       matrix:
         rust:
-          - 1.53.0 # STABLE
+          - 1.56.0 # STABLE
           - 1.46.0 # MSRV
         features:
           - default
           - minimal
           - all-keys
-          - minimal,esplora
+          - minimal,use-esplora-ureq
           - key-value-db
           - electrum
           - compact_filters
-          - esplora,key-value-db,electrum
+          - esplora,ureq,key-value-db,electrum
           - compiler
           - rpc
+          - verify
+          - async-interface
+          - use-esplora-reqwest
+          - sqlite
     steps:
       - name: checkout
         uses: actions/checkout@v2
@@ -75,29 +79,20 @@ jobs:
         run: cargo test --features test-md-docs --no-default-features -- doctest::ReadmeDoctests
 
   test-blockchains:
-    name: Test ${{ matrix.blockchain.name }}
-    runs-on: ubuntu-16.04
+    name: Blockchain ${{ matrix.blockchain.features }}
+    runs-on: ubuntu-20.04
     strategy:
       fail-fast: false
       matrix:
         blockchain:
           - name: electrum
-            container: bitcoindevkit/electrs:0.4.0
-            start: /root/electrs --network regtest --cookie-file $GITHUB_WORKSPACE/.bitcoin/regtest/.cookie --jsonrpc-import
-          - name: esplora
-            container: bitcoindevkit/esplora:0.4.0
-            start: /root/electrs --network regtest -vvv --daemon-dir $GITHUB_WORKSPACE/.bitcoin --jsonrpc-import --electrum-rpc-addr=0.0.0.0:60401 --http-addr 0.0.0.0:3002
+            features: test-electrum
           - name: rpc
-            container: bitcoindevkit/electrs:0.4.0
-            start: /root/electrs --network regtest --cookie-file $GITHUB_WORKSPACE/.bitcoin/regtest/.cookie --jsonrpc-import
-    container: ${{ matrix.blockchain.container }}
-    env:
-      BDK_RPC_AUTH: COOKIEFILE
-      BDK_RPC_COOKIEFILE: ${{ github.workspace }}/.bitcoin/regtest/.cookie
-      BDK_RPC_URL: 127.0.0.1:18443
-      BDK_RPC_WALLET: bdk-test
-      BDK_ELECTRUM_URL: tcp://127.0.0.1:60401
-      BDK_ESPLORA_URL: http://127.0.0.1:3002
+            features: test-rpc
+          - name: esplora
+            features: test-esplora,use-esplora-reqwest
+          - name: esplora
+            features: test-esplora,use-esplora-ureq    
     steps:
       - name: Checkout
         uses: actions/checkout@v2
@@ -109,26 +104,17 @@ jobs:
             ~/.cargo/git
             target
           key: ${{ runner.os }}-cargo-${{ github.job }}-${{ hashFiles('**/Cargo.toml','**/Cargo.lock') }}
-      - name: get pkg-config # running esplora tests seems to need this
-        run: apt update && apt install -y --fix-missing pkg-config libssl-dev
-      - name: Install rustup
-        run: curl https://sh.rustup.rs -sSf | sh -s -- -y
-      - name: Set default toolchain
-        run: $HOME/.cargo/bin/rustup default 1.53.0 # STABLE
-      - name: Set profile
-        run: $HOME/.cargo/bin/rustup set profile minimal
-      - name: Update toolchain
-        run: $HOME/.cargo/bin/rustup update
-      - name: Start core
-        run: ./ci/start-core.sh
-      - name: start ${{ matrix.blockchain.name }}
-        run: nohup ${{ matrix.blockchain.start }} & sleep 5
+      - name: Setup rust toolchain
+        uses: actions-rs/toolchain@v1
+        with:
+          toolchain: stable
+          override: true
       - name: Test
-        run: $HOME/.cargo/bin/cargo test --features test-${{ matrix.blockchain.name }},test-blockchains --no-default-features ${{ matrix.blockchain.name }}::bdk_blockchain_tests
-
+        run: cargo test --no-default-features --features ${{ matrix.blockchain.features }} ${{ matrix.blockchain.name }}::bdk_blockchain_tests
+  
   check-wasm:
     name: Check WASM
-    runs-on: ubuntu-16.04
+    runs-on: ubuntu-20.04
     env:
       CC: clang-10
       CFLAGS: -I/usr/include
@@ -145,11 +131,11 @@ jobs:
           key: ${{ runner.os }}-cargo-${{ github.job }}-${{ hashFiles('**/Cargo.toml','**/Cargo.lock') }}
         # Install a recent version of clang that supports wasm32
       - run: wget -O - https://apt.llvm.org/llvm-snapshot.gpg.key | sudo apt-key add - || exit 1
-      - run: sudo apt-add-repository "deb http://apt.llvm.org/xenial/ llvm-toolchain-xenial-10 main" || exit 1
+      - run: sudo apt-add-repository "deb http://apt.llvm.org/focal/ llvm-toolchain-focal-10 main" || exit 1
       - run: sudo apt-get update || exit 1
       - run: sudo apt-get install -y libclang-common-10-dev clang-10 libc6-dev-i386 || exit 1
       - name: Set default toolchain
-        run: rustup default 1.53.0 # STABLE
+        run: rustup default 1.56.0 # STABLE
       - name: Set profile
         run: rustup set profile minimal
       - name: Add target wasm32
@@ -157,7 +143,7 @@ jobs:
       - name: Update toolchain
         run: rustup update
       - name: Check
-        run: cargo check --target wasm32-unknown-unknown --features esplora --no-default-features
+        run: cargo check --target wasm32-unknown-unknown --features use-esplora-reqwest --no-default-features
 
   fmt:
     name: Rust fmt

.github/workflows/nightly_docs.yml

@@ -24,7 +24,7 @@ jobs:
       - name: Update toolchain
         run: rustup update
       - name: Build docs
-        run: cargo rustdoc --verbose --features=compiler,electrum,esplora,compact_filters,key-value-db,all-keys -- --cfg docsrs -Dwarnings
+        run: cargo rustdoc --verbose --features=compiler,electrum,esplora,ureq,compact_filters,key-value-db,all-keys,sqlite -- --cfg docsrs -Dwarnings
       - name: Upload artifact
         uses: actions/upload-artifact@v2
         with:

CHANGELOG.md

@@ -6,9 +6,40 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+## [v0.13.0] - [v0.12.0]
+
+- Exposed `get_tx()` method from `Database` to `Wallet`.
+
+## [v0.12.0] - [v0.11.0]
+
+- Activate `miniscript/use-serde` feature to allow consumers of the library to access it via the re-exported `miniscript` crate.
+- Add support for proxies in `EsploraBlockchain`
+- Added `SqliteDatabase` that implements `Database` backed by a sqlite database using `rusqlite` crate.
+
+## [v0.11.0] - [v0.10.0]
+
+- Added `flush` method to the `Database` trait to explicitly flush to disk latest changes on the db.
+
+## [v0.10.0] - [v0.9.0]
+
+- Added `RpcBlockchain` in the `AnyBlockchain` struct to allow using Rpc backend where `AnyBlockchain` is used (eg `bdk-cli`)
+- Removed hard dependency on `tokio`.
+
 ### Wallet
-#### Added
-- Bitcoin core RPC added as blockchain backend
+
+- Removed and replaced `set_single_recipient` with more general `drain_to` and replaced `maintain_single_recipient` with `allow_shrinking`.
+
+### Blockchain
+
+- Removed `stop_gap` from `Blockchain` trait and added it to only `ElectrumBlockchain` and `EsploraBlockchain` structs.
+- Added a `ureq` backend for use when not using feature `async-interface` or target WASM. `ureq` is a blocking HTTP client.
+
+## [v0.9.0] - [v0.8.0]
+
+### Wallet
+
+- Added Bitcoin core RPC added as blockchain backend
+- Added a `verify` feature that can be enable to verify the unconfirmed txs we download against the consensus rules
 
 ## [v0.8.0] - [v0.7.0]
 
@@ -343,7 +374,7 @@ final transaction is created by calling `finish` on the builder.
 - Use `MemoryDatabase` in the compiler example
 - Make the REPL return JSON
 
-[unreleased]: https://github.com/bitcoindevkit/bdk/compare/v0.8.0...HEAD
+[unreleased]: https://github.com/bitcoindevkit/bdk/compare/v0.11.0...HEAD
 [0.1.0-beta.1]: https://github.com/bitcoindevkit/bdk/compare/96c87ea5...0.1.0-beta.1
 [v0.2.0]: https://github.com/bitcoindevkit/bdk/compare/0.1.0-beta.1...v0.2.0
 [v0.3.0]: https://github.com/bitcoindevkit/bdk/compare/v0.2.0...v0.3.0
@@ -353,3 +384,8 @@ final transaction is created by calling `finish` on the builder.
 [v0.6.0]: https://github.com/bitcoindevkit/bdk/compare/v0.5.1...v0.6.0
 [v0.7.0]: https://github.com/bitcoindevkit/bdk/compare/v0.6.0...v0.7.0
 [v0.8.0]: https://github.com/bitcoindevkit/bdk/compare/v0.7.0...v0.8.0
+[v0.9.0]: https://github.com/bitcoindevkit/bdk/compare/v0.8.0...v0.9.0
+[v0.10.0]: https://github.com/bitcoindevkit/bdk/compare/v0.9.0...v0.10.0
+[v0.11.0]: https://github.com/bitcoindevkit/bdk/compare/v0.10.0...v0.11.0
+[v0.12.0]: https://github.com/bitcoindevkit/bdk/compare/v0.11.0...v0.12.0
+[v0.13.0]: https://github.com/bitcoindevkit/bdk/compare/v0.12.0...v0.13.0

CONTRIBUTING.md

@@ -57,6 +57,21 @@ comment suggesting that you're working on it. If someone is already assigned,
 don't hesitate to ask if the assigned party or previous commenters are still
 working on it if it has been awhile.
 
+Deprecation policy
+------------------
+
+Where possible, breaking existing APIs should be avoided. Instead, add new APIs and
+use [`#[deprecated]`](https://github.com/rust-lang/rfcs/blob/master/text/1270-deprecation.md)
+to discourage use of the old one.
+
+Deprecated APIs are typically maintained for one release cycle. In other words, an
+API that has been deprecated with the 0.10 release can be expected to be removed in the
+0.11 release. This allows for smoother upgrades without incurring too much technical
+debt inside this library.
+
+If you deprecated an API as part of a contribution, we encourage you to "own" that API
+and send a follow-up to remove it as part of the next release cycle.
+
 Peer review
 -----------
 

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "bdk"
-version = "0.8.1-dev"
+version = "0.13.0"
 edition = "2018"
 authors = ["Alekos Filini <alekos.filini@gmail.com>", "Riccardo Casatta <riccardo@casatta.it>"]
 homepage = "https://bitcoindevkit.org"
@@ -12,29 +12,40 @@ readme = "README.md"
 license = "MIT OR Apache-2.0"
 
 [dependencies]
-bdk-macros = "^0.4"
+bdk-macros = "^0.6"
 log = "^0.4"
-miniscript = "5.1"
-bitcoin = { version = "~0.26.2", features = ["use-serde", "base64"] }
+miniscript = { version = "^6.0", features = ["use-serde"] }
+bitcoin = { version = "^0.27", features = ["use-serde", "base64"] }
 serde = { version = "^1.0", features = ["derive"] }
 serde_json = { version = "^1.0" }
 rand = "^0.7"
 
 # Optional dependencies
 sled = { version = "0.34", optional = true }
-electrum-client = { version = "0.7", optional = true }
+electrum-client = { version = "0.8", optional = true }
+rusqlite = { version = "0.25.3", optional = true }
+ahash = { version = "=0.7.4", optional = true }
 reqwest = { version = "0.11", optional = true, features = ["json"] }
+ureq = { version = "~2.2.0", features = ["json"], optional = true }
 futures = { version = "0.3", optional = true }
 async-trait = { version = "0.1", optional = true }
-rocksdb = { version = "0.14", optional = true }
+rocksdb = { version = "0.14", default-features = false, features = ["snappy"], optional = true }
 cc = { version = ">=1.0.64", optional = true }
 socks = { version = "0.3", optional = true }
 lazy_static = { version = "1.4", optional = true }
-tiny-bip39 = { version = "^0.8", optional = true }
+
+# the latest 0.8 version of tiny-bip39 depends on zeroize_derive 1.2 which has MSRV 1.51 and our 
+# MSRV is 1.46, to fix this until we update our MSRV or replace the tiny-bip39 
+# dependency https://github.com/bitcoindevkit/bdk/issues/399 we can only use an older version
+tiny-bip39 = { version = "< 0.8", optional = true }
+# backtrace > 0.3.61 includes object v0.27 which doesn't compile on 1.46. this is used by
+# tiny-bip39
+backtrace = { version = "=0.3.61", optional = true }
+
+bitcoinconsensus = { version = "0.19.0-3", optional = true }
 
 # Needed by bdk_blockchain_tests macro
-bitcoincore-rpc = { version = "0.13", optional = true }
-serial_test = { version = "0.4", optional = true }
+bitcoincore-rpc = { version = "0.14", optional = true }
 
 # Platform-specific dependencies
 [target.'cfg(not(target_arch = "wasm32"))'.dependencies]
@@ -48,30 +59,49 @@ rand = { version = "^0.7", features = ["wasm-bindgen"] }
 [features]
 minimal = []
 compiler = ["miniscript/compiler"]
+verify = ["bitcoinconsensus"]
 default = ["key-value-db", "electrum"]
-electrum = ["electrum-client"]
-esplora = ["reqwest", "futures"]
+sqlite = ["rusqlite", "ahash"]
 compact_filters = ["rocksdb", "socks", "lazy_static", "cc"]
 key-value-db = ["sled"]
-async-interface = ["async-trait"]
 all-keys = ["keys-bip39"]
-keys-bip39 = ["tiny-bip39"]
+keys-bip39 = ["tiny-bip39", "backtrace"]
 rpc = ["bitcoincore-rpc"]
 
+# We currently provide mulitple implementations of `Blockchain`, all are
+# blocking except for the `EsploraBlockchain` which can be either async or
+# blocking, depending on the HTTP client in use.
+#
+# - Users wanting asynchronous HTTP calls should enable `async-interface` to get
+#   access to the asynchronous method implementations. Then, if Esplora is wanted,
+#   enable `esplora` AND `reqwest` (`--features=use-esplora-reqwest`).
+# - Users wanting blocking HTTP calls can use any of the other blockchain
+#   implementations (`compact_filters`, `electrum`, or `esplora`). Users wanting to
+#   use Esplora should enable `esplora` AND `ureq`  (`--features=use-esplora-ureq`).
+#
+# WARNING: Please take care with the features below, various combinations will
+# fail to build. We cannot currently build `bdk` with `--all-features`.
+async-interface = ["async-trait"]
+electrum = ["electrum-client"]
+# MUST ALSO USE `--no-default-features`.
+use-esplora-reqwest = ["esplora", "reqwest", "reqwest/socks", "futures"]
+use-esplora-ureq = ["esplora", "ureq", "ureq/socks"]
+# Typical configurations will not need to use `esplora` feature directly.
+esplora = []
+
 
 # Debug/Test features
 test-blockchains = ["bitcoincore-rpc", "electrum-client"]
-test-electrum = ["electrum"]
-test-rpc = ["rpc"]
-test-esplora = ["esplora"]
+test-electrum = ["electrum", "electrsd/electrs_0_8_10", "test-blockchains"]
+test-rpc = ["rpc", "electrsd/electrs_0_8_10", "test-blockchains"]
+test-esplora = ["electrsd/legacy", "electrsd/esplora_a33e97e1", "test-blockchains"]
 test-md-docs = ["electrum"]
 
 [dev-dependencies]
 lazy_static = "1.4"
 env_logger = "0.7"
 clap = "2.33"
-serial_test = "0.4"
-bitcoind = "0.10.0"
+electrsd = { version= "0.12", features = ["trigger", "bitcoind_0_21_1"] }
 
 [[example]]
 name = "address_validator"
@@ -87,6 +117,6 @@ required-features = ["compiler"]
 [workspace]
 members = ["macros"]
 [package.metadata.docs.rs]
-features = ["compiler", "electrum", "esplora", "compact_filters", "key-value-db", "all-keys"]
+features = ["compiler", "electrum", "esplora", "ureq", "compact_filters", "rpc", "key-value-db", "sqlite", "all-keys", "verify"]
 # defines the configuration attribute `docsrs`
 rustdoc-args = ["--cfg", "docsrs"]

DEVELOPMENT_CYCLE.md

@@ -32,14 +32,14 @@ Pre-`v1.0.0` our "major" releases only affect the "minor" semver value. Accordin
     - If it's a minor issue you can just fix it in the release branch, since it will be merged back to `master` eventually
     - For bigger issues you can fix them on `master` and then *cherry-pick* the commit to the release branch
 6. Update the changelog with the new release version.
-7. Update `src/lib.rs` with the new version (line ~59)
+7. Update `src/lib.rs` with the new version (line ~43)
 8. On release day, make a commit on the release branch to bump the version to `x.y.z`. The message should be "Bump version to x.y.z".
 9. Add a tag to this commit. The tag name should be `vx.y.z` (for example `v0.5.0`), and the message "Release x.y.z". Make sure the tag is signed, for extra safety use the explicit `--sign` flag.
 10. Push the new commits to the upstream release branch, wait for the CI to finish one last time.
 11. Publish **all** the updated crates to crates.io.
 12. Make a new commit to bump the version value to `x.y.(z+1)-dev`. The message should be "Bump version to x.y.(z+1)-dev".
 13. Merge the release branch back into `master`.
-14. If the `master` branch contains any unreleased changes to the `bdk-macros`, `bdk-testutils`, or `bdk-testutils-macros` crates, change the `bdk` Cargo.toml `[dev-dependencies]` to point to the local path (ie. `bdk-testutils-macros = { path = "./testutils-macros"}`)
+14. If the `master` branch contains any unreleased changes to the `bdk-macros` crate, change the `bdk` Cargo.toml `[dependencies]` to point to the local path (ie. `bdk-macros = { path = "./macros"}`)
 15. Create the release on GitHub: go to "tags", click on the dots on the right and select "Create Release". Then set the title to `vx.y.z` and write down some brief release notes.
 16. Make sure the new release shows up on crates.io and that the docs are built correctly on docs.rs.
 17. Announce the release on Twitter, Discord and Telegram.

README.md

@@ -151,6 +151,25 @@ fn main() -> Result<(), bdk::Error> {
 }
 ```
 
+## Testing
+
+### Unit testing
+
+```
+cargo test
+```
+
+### Integration testing
+
+Integration testing require testing features, for example:
+
+```
+cargo test --features test-electrum
+```
+
+The other options are `test-esplora` or `test-rpc`.
+Note that `electrs` and `bitcoind` binaries are automatically downloaded (on mac and linux), to specify you already have installed binaries you must use `--no-default-features` and provide `BITCOIND_EXE` and `ELECTRS_EXE` as environment variables.
+
 ## License
 
 Licensed under either of

examples/compiler.rs

@@ -70,7 +70,7 @@ fn main() -> Result<(), Box<dyn Error>> {
     let policy_str = matches.value_of("POLICY").unwrap();
     info!("Compiling policy: {}", policy_str);
 
-    let policy = Concrete::<String>::from_str(&policy_str)?;
+    let policy = Concrete::<String>::from_str(policy_str)?;
 
     let descriptor = match matches.value_of("TYPE").unwrap() {
         "sh" => Descriptor::new_sh(policy.compile()?)?,

macros/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "bdk-macros"
-version = "0.4.0"
+version = "0.6.0"
 authors = ["Alekos Filini <alekos.filini@gmail.com>"]
 edition = "2018"
 homepage = "https://bitcoindevkit.org"

run_blockchain_tests.sh

@@ -1,71 +0,0 @@
-#!/bin/sh
-
-usage() {
-    cat <<'EOF'
-Script for running the bdk blockchain tests for a specific blockchain by starting up the backend in docker.
-
-Usage: ./run_blockchain_tests.sh [esplora|electrum|rpc] [test name].
-
-EOF
-}
-
-eprintln(){
-    echo "$@" >&2
-}
-
-cleanup() {
-    if test "$id"; then
-        eprintln "cleaning up $blockchain docker container $id";
-        docker rm -fv "$id" > /dev/null;
-        rm /tmp/regtest-"$id".cookie;
-    fi
-    trap - EXIT INT
-}
-
-# Makes sure we clean up the container at the end or if ^C
-trap 'rc=$?; cleanup; exit $rc' EXIT INT
-
-blockchain="$1"
-test_name="$2"
-
-case "$blockchain" in
-    electrum)
-        eprintln "starting electrs docker container"
-        id="$(docker run --detach -p 127.0.0.1:18443-18444:18443-18444/tcp -p 127.0.0.1:60401:60401/tcp bitcoindevkit/electrs:0.4.0)"
-        ;;
-    esplora)
-        eprintln "starting esplora docker container"
-        id="$(docker run --detach -p 127.0.0.1:18443-18444:18443-18444/tcp -p 127.0.0.1:60401:60401/tcp -p 127.0.0.1:3002:3002/tcp bitcoindevkit/esplora:0.4.0)"
-        export BDK_ESPLORA_URL=http://127.0.0.1:3002
-        ;;
-    rpc)
-        eprintln "starting bitcoind docker container (via electrs container)"
-        id="$(docker run --detach -p 127.0.0.1:18443-18444:18443-18444/tcp -p 127.0.0.1:60401:60401/tcp bitcoindevkit/electrs:0.4.0)"      
-        ;;
-    *)
-        usage;
-        exit 1;
-        ;;
-    esac
-
-# taken from https://github.com/bitcoindevkit/bitcoin-regtest-box
-export BDK_RPC_AUTH=COOKIEFILE
-export BDK_RPC_COOKIEFILE=/tmp/regtest-"$id".cookie
-export BDK_RPC_URL=127.0.0.1:18443
-export BDK_RPC_WALLET=bdk-test
-export BDK_ELECTRUM_URL=tcp://127.0.0.1:60401
-
-cli(){
-    docker exec -it "$id" /root/bitcoin-cli -regtest -datadir=/root/.bitcoin $@
-}
-
-#eprintln "running getwalletinfo until bitcoind seems to be alive"
-while ! cli getwalletinfo >/dev/null; do sleep 1; done
-
-# sleep again for good measure!
-sleep 1;
-
-# copy bitcoind cookie file to /tmp
-docker cp "$id":/root/.bitcoin/regtest/.cookie /tmp/regtest-"$id".cookie
-
-cargo test --features "test-blockchains,test-$blockchain" --no-default-features "$blockchain::bdk_blockchain_tests::$test_name"

src/blockchain/any.rs

@@ -37,9 +37,9 @@
 //! )?;
 //! # }
 //!
-//! # #[cfg(feature = "esplora")]
+//! # #[cfg(all(feature = "esplora", feature = "ureq"))]
 //! # {
-//! let esplora_blockchain = EsploraBlockchain::new("...", None);
+//! let esplora_blockchain = EsploraBlockchain::new("...", 20);
 //! let wallet_esplora: Wallet<AnyBlockchain, _> = Wallet::new(
 //!     "...",
 //!     None,
@@ -60,6 +60,8 @@
 //! # use bdk::blockchain::*;
 //! # use bdk::database::MemoryDatabase;
 //! # use bdk::Wallet;
+//! # #[cfg(all(feature = "esplora", feature = "ureq"))]
+//! # {
 //! let config = serde_json::from_str("...")?;
 //! let blockchain = AnyBlockchain::from_config(&config)?;
 //! let wallet = Wallet::new(
@@ -69,6 +71,7 @@
 //!     MemoryDatabase::default(),
 //!     blockchain,
 //! )?;
+//! # }
 //! # Ok::<(), bdk::Error>(())
 //! ```
 
@@ -94,6 +97,8 @@ macro_rules! impl_inner_method {
             AnyBlockchain::Esplora(inner) => inner.$name( $($args, )* ),
             #[cfg(feature = "compact_filters")]
             AnyBlockchain::CompactFilters(inner) => inner.$name( $($args, )* ),
+            #[cfg(feature = "rpc")]
+            AnyBlockchain::Rpc(inner) => inner.$name( $($args, )* ),
         }
     }
 }
@@ -116,6 +121,10 @@ pub enum AnyBlockchain {
     #[cfg_attr(docsrs, doc(cfg(feature = "compact_filters")))]
     /// Compact filters client
     CompactFilters(compact_filters::CompactFiltersBlockchain),
+    #[cfg(feature = "rpc")]
+    #[cfg_attr(docsrs, doc(cfg(feature = "rpc")))]
+    /// RPC client
+    Rpc(rpc::RpcBlockchain),
 }
 
 #[maybe_async]
@@ -126,31 +135,17 @@ impl Blockchain for AnyBlockchain {
 
     fn setup<D: BatchDatabase, P: 'static + Progress>(
         &self,
-        stop_gap: Option<usize>,
         database: &mut D,
         progress_update: P,
     ) -> Result<(), Error> {
-        maybe_await!(impl_inner_method!(
-            self,
-            setup,
-            stop_gap,
-            database,
-            progress_update
-        ))
+        maybe_await!(impl_inner_method!(self, setup, database, progress_update))
     }
     fn sync<D: BatchDatabase, P: 'static + Progress>(
         &self,
-        stop_gap: Option<usize>,
         database: &mut D,
         progress_update: P,
     ) -> Result<(), Error> {
-        maybe_await!(impl_inner_method!(
-            self,
-            sync,
-            stop_gap,
-            database,
-            progress_update
-        ))
+        maybe_await!(impl_inner_method!(self, sync, database, progress_update))
     }
 
     fn get_tx(&self, txid: &Txid) -> Result<Option<Transaction>, Error> {
@@ -171,6 +166,7 @@ impl Blockchain for AnyBlockchain {
 impl_from!(electrum::ElectrumBlockchain, AnyBlockchain, Electrum, #[cfg(feature = "electrum")]);
 impl_from!(esplora::EsploraBlockchain, AnyBlockchain, Esplora, #[cfg(feature = "esplora")]);
 impl_from!(compact_filters::CompactFiltersBlockchain, AnyBlockchain, CompactFilters, #[cfg(feature = "compact_filters")]);
+impl_from!(rpc::RpcBlockchain, AnyBlockchain, Rpc, #[cfg(feature = "rpc")]);
 
 /// Type that can contain any of the blockchain configurations defined by the library
 ///
@@ -188,7 +184,8 @@ impl_from!(compact_filters::CompactFiltersBlockchain, AnyBlockchain, CompactFilt
 ///     r#"{
 ///    "type" : "electrum",
 ///    "url" : "ssl://electrum.blockstream.info:50002",
-///    "retry": 2
+///    "retry": 2,
+///    "stop_gap": 20
 /// }"#,
 /// )
 /// .unwrap();
@@ -198,7 +195,8 @@ impl_from!(compact_filters::CompactFiltersBlockchain, AnyBlockchain, CompactFilt
 ///         url: "ssl://electrum.blockstream.info:50002".into(),
 ///         retry: 2,
 ///         socks5: None,
-///         timeout: None
+///         timeout: None,
+///         stop_gap: 20,
 ///     })
 /// );
 /// # }
@@ -218,6 +216,10 @@ pub enum AnyBlockchainConfig {
     #[cfg_attr(docsrs, doc(cfg(feature = "compact_filters")))]
     /// Compact filters client
     CompactFilters(compact_filters::CompactFiltersBlockchainConfig),
+    #[cfg(feature = "rpc")]
+    #[cfg_attr(docsrs, doc(cfg(feature = "rpc")))]
+    /// RPC client configuration
+    Rpc(rpc::RpcConfig),
 }
 
 impl ConfigurableBlockchain for AnyBlockchain {
@@ -237,6 +239,10 @@ impl ConfigurableBlockchain for AnyBlockchain {
             AnyBlockchainConfig::CompactFilters(inner) => AnyBlockchain::CompactFilters(
                 compact_filters::CompactFiltersBlockchain::from_config(inner)?,
             ),
+            #[cfg(feature = "rpc")]
+            AnyBlockchainConfig::Rpc(inner) => {
+                AnyBlockchain::Rpc(rpc::RpcBlockchain::from_config(inner)?)
+            }
         })
     }
 }
@@ -244,3 +250,4 @@ impl ConfigurableBlockchain for AnyBlockchain {
 impl_from!(electrum::ElectrumBlockchainConfig, AnyBlockchainConfig, Electrum, #[cfg(feature = "electrum")]);
 impl_from!(esplora::EsploraBlockchainConfig, AnyBlockchainConfig, Esplora, #[cfg(feature = "esplora")]);
 impl_from!(compact_filters::CompactFiltersBlockchainConfig, AnyBlockchainConfig, CompactFilters, #[cfg(feature = "compact_filters")]);
+impl_from!(rpc::RpcConfig, AnyBlockchainConfig, Rpc, #[cfg(feature = "rpc")]);

src/blockchain/compact_filters/mod.rs

@@ -207,6 +207,7 @@ impl CompactFiltersBlockchain {
                 received: incoming,
                 sent: outgoing,
                 confirmation_time: ConfirmationTime::new(height, timestamp),
+                verified: height.is_some(),
                 fee: Some(inputs_sum.saturating_sub(outputs_sum)),
             };
 
@@ -228,7 +229,6 @@ impl Blockchain for CompactFiltersBlockchain {
     #[allow(clippy::mutex_atomic)] // Mutex is easier to understand than a CAS loop.
     fn setup<D: BatchDatabase, P: 'static + Progress>(
         &self,
-        _stop_gap: Option<usize>, // TODO: move to electrum and esplora only
         database: &mut D,
         progress_update: P,
     ) -> Result<(), Error> {
@@ -254,7 +254,7 @@ impl Blockchain for CompactFiltersBlockchain {
         let total_cost = headers_cost + filters_cost + PROCESS_BLOCKS_COST;
 
         if let Some(snapshot) = sync::sync_headers(
-            Arc::clone(&first_peer),
+            Arc::clone(first_peer),
             Arc::clone(&self.headers),
             |new_height| {
                 let local_headers_cost =
@@ -275,7 +275,7 @@ impl Blockchain for CompactFiltersBlockchain {
         let buried_height = synced_height.saturating_sub(sync::BURIED_CONFIRMATIONS);
         info!("Synced headers to height: {}", synced_height);
 
-        cf_sync.prepare_sync(Arc::clone(&first_peer))?;
+        cf_sync.prepare_sync(Arc::clone(first_peer))?;
 
         let all_scripts = Arc::new(
             database
@@ -294,7 +294,7 @@ impl Blockchain for CompactFiltersBlockchain {
         let mut threads = Vec::with_capacity(self.peers.len());
         for peer in &self.peers {
             let cf_sync = Arc::clone(&cf_sync);
-            let peer = Arc::clone(&peer);
+            let peer = Arc::clone(peer);
             let headers = Arc::clone(&self.headers);
             let all_scripts = Arc::clone(&all_scripts);
             let last_synced_block = Arc::clone(&last_synced_block);

src/blockchain/compact_filters/peer.rs

@@ -262,7 +262,7 @@ impl Peer {
         let message_resp = {
             let mut lock = responses.write().unwrap();
             let message_resp = lock.entry(wait_for).or_default();
-            Arc::clone(&message_resp)
+            Arc::clone(message_resp)
         };
 
         let (lock, cvar) = &*message_resp;
@@ -379,7 +379,7 @@ impl Peer {
             let message_resp = {
                 let mut lock = reader_thread_responses.write().unwrap();
                 let message_resp = lock.entry(in_message.cmd()).or_default();
-                Arc::clone(&message_resp)
+                Arc::clone(message_resp)
             };
 
             let (lock, cvar) = &*message_resp;

src/blockchain/compact_filters/store.rs

@@ -760,7 +760,7 @@ impl CfStore {
         let cf_headers: Vec<FilterHeader> = filter_hashes
             .into_iter()
             .scan(checkpoint, |prev_header, filter_hash| {
-                let filter_header = filter_hash.filter_header(&prev_header);
+                let filter_header = filter_hash.filter_header(prev_header);
                 *prev_header = filter_header;
 
                 Some(filter_header)
@@ -801,7 +801,7 @@ impl CfStore {
             .zip(headers.into_iter())
             .scan(checkpoint, |prev_header, ((_, filter_content), header)| {
                 let filter = BlockFilter::new(&filter_content);
-                if header != filter.filter_header(&prev_header) {
+                if header != filter.filter_header(prev_header) {
                     return Some(Err(CompactFiltersError::InvalidFilter));
                 }
                 *prev_header = header;

src/blockchain/compact_filters/sync.rs

@@ -205,7 +205,7 @@ impl CfSync {
                     let block_hash = self.headers_store.get_block_hash(height)?.unwrap();
 
                     // TODO: also download random blocks?
-                    if process(&block_hash, &BlockFilter::new(&filter))? {
+                    if process(&block_hash, &BlockFilter::new(filter))? {
                         log::debug!("Downloading block {}", block_hash);
 
                         let block = peer

src/blockchain/electrum.rs

@@ -43,11 +43,17 @@ use crate::FeeRate;
 ///
 /// ## Example
 /// See the [`blockchain::electrum`](crate::blockchain::electrum) module for a usage example.
-pub struct ElectrumBlockchain(Client);
+pub struct ElectrumBlockchain {
+    client: Client,
+    stop_gap: usize,
+}
 
 impl std::convert::From<Client> for ElectrumBlockchain {
     fn from(client: Client) -> Self {
-        ElectrumBlockchain(client)
+        ElectrumBlockchain {
+            client,
+            stop_gap: 20,
+        }
     }
 }
 
@@ -64,34 +70,33 @@ impl Blockchain for ElectrumBlockchain {
 
     fn setup<D: BatchDatabase, P: Progress>(
         &self,
-        stop_gap: Option<usize>,
         database: &mut D,
         progress_update: P,
     ) -> Result<(), Error> {
-        self.0
-            .electrum_like_setup(stop_gap, database, progress_update)
+        self.client
+            .electrum_like_setup(self.stop_gap, database, progress_update)
     }
 
     fn get_tx(&self, txid: &Txid) -> Result<Option<Transaction>, Error> {
-        Ok(self.0.transaction_get(txid).map(Option::Some)?)
+        Ok(self.client.transaction_get(txid).map(Option::Some)?)
     }
 
     fn broadcast(&self, tx: &Transaction) -> Result<(), Error> {
-        Ok(self.0.transaction_broadcast(tx).map(|_| ())?)
+        Ok(self.client.transaction_broadcast(tx).map(|_| ())?)
     }
 
     fn get_height(&self) -> Result<u32, Error> {
         // TODO: unsubscribe when added to the client, or is there a better call to use here?
 
         Ok(self
-            .0
+            .client
             .block_headers_subscribe()
             .map(|data| data.height as u32)?)
     }
 
     fn estimate_fee(&self, target: usize) -> Result<FeeRate, Error> {
         Ok(FeeRate::from_btc_per_kvb(
-            self.0.estimate_fee(target)? as f32
+            self.client.estimate_fee(target)? as f32
         ))
     }
 }
@@ -149,6 +154,8 @@ pub struct ElectrumBlockchainConfig {
     pub retry: u8,
     /// Request timeout (seconds)
     pub timeout: Option<u8>,
+    /// Stop searching addresses for transactions after finding an unused gap of this length
+    pub stop_gap: usize,
 }
 
 impl ConfigurableBlockchain for ElectrumBlockchain {
@@ -162,16 +169,17 @@ impl ConfigurableBlockchain for ElectrumBlockchain {
             .socks5(socks5)?
             .build();
 
-        Ok(ElectrumBlockchain(Client::from_config(
-            config.url.as_str(),
-            electrum_config,
-        )?))
+        Ok(ElectrumBlockchain {
+            client: Client::from_config(config.url.as_str(), electrum_config)?,
+            stop_gap: config.stop_gap,
+        })
     }
 }
 
-#[cfg(feature = "test-blockchains")]
+#[cfg(test)]
+#[cfg(feature = "test-electrum")]
 crate::bdk_blockchain_tests! {
-    fn test_instance() -> ElectrumBlockchain {
-        ElectrumBlockchain::from(Client::new(&testutils::blockchain_tests::get_electrum_url()).unwrap())
+    fn test_instance(test_client: &TestClient) -> ElectrumBlockchain {
+        ElectrumBlockchain::from(Client::new(&test_client.electrsd.electrum_url).unwrap())
     }
 }

src/blockchain/esplora/mod.rs

@@ -0,0 +1,129 @@
+//! Esplora
+//!
+//! This module defines a [`EsploraBlockchain`] struct that can query an Esplora
+//! backend populate the wallet's [database](crate::database::Database) by:
+//!
+//! ## Example
+//!
+//! ```no_run
+//! # use bdk::blockchain::esplora::EsploraBlockchain;
+//! let blockchain = EsploraBlockchain::new("https://blockstream.info/testnet/api", 20);
+//! # Ok::<(), bdk::Error>(())
+//! ```
+//!
+//! Esplora blockchain can use either `ureq` or `reqwest` for the HTTP client
+//! depending on your needs (blocking or async respectively).
+//!
+//! Please note, to configure the Esplora HTTP client correctly use one of:
+//! Blocking:  --features='esplora,ureq'
+//! Async:     --features='async-interface,esplora,reqwest' --no-default-features
+use std::collections::HashMap;
+use std::fmt;
+use std::io;
+
+use serde::Deserialize;
+
+use bitcoin::consensus;
+use bitcoin::{BlockHash, Txid};
+
+use crate::error::Error;
+use crate::FeeRate;
+
+#[cfg(feature = "reqwest")]
+mod reqwest;
+
+#[cfg(feature = "reqwest")]
+pub use self::reqwest::*;
+
+#[cfg(feature = "ureq")]
+mod ureq;
+
+#[cfg(feature = "ureq")]
+pub use self::ureq::*;
+
+fn into_fee_rate(target: usize, estimates: HashMap<String, f64>) -> Result<FeeRate, Error> {
+    let fee_val = estimates
+        .into_iter()
+        .map(|(k, v)| Ok::<_, std::num::ParseIntError>((k.parse::<usize>()?, v)))
+        .collect::<Result<Vec<_>, _>>()
+        .map_err(|e| Error::Generic(e.to_string()))?
+        .into_iter()
+        .take_while(|(k, _)| k <= &target)
+        .map(|(_, v)| v)
+        .last()
+        .unwrap_or(1.0);
+
+    Ok(FeeRate::from_sat_per_vb(fee_val as f32))
+}
+
+/// Data type used when fetching transaction history from Esplora.
+#[derive(Deserialize)]
+pub struct EsploraGetHistory {
+    txid: Txid,
+    status: EsploraGetHistoryStatus,
+}
+
+#[derive(Deserialize)]
+struct EsploraGetHistoryStatus {
+    block_height: Option<usize>,
+}
+
+/// Errors that can happen during a sync with [`EsploraBlockchain`]
+#[derive(Debug)]
+pub enum EsploraError {
+    /// Error during ureq HTTP request
+    #[cfg(feature = "ureq")]
+    Ureq(::ureq::Error),
+    /// Transport error during the ureq HTTP call
+    #[cfg(feature = "ureq")]
+    UreqTransport(::ureq::Transport),
+    /// Error during reqwest HTTP request
+    #[cfg(feature = "reqwest")]
+    Reqwest(::reqwest::Error),
+    /// HTTP response error
+    HttpResponse(u16),
+    /// IO error during ureq response read
+    Io(io::Error),
+    /// No header found in ureq response
+    NoHeader,
+    /// Invalid number returned
+    Parsing(std::num::ParseIntError),
+    /// Invalid Bitcoin data returned
+    BitcoinEncoding(bitcoin::consensus::encode::Error),
+    /// Invalid Hex data returned
+    Hex(bitcoin::hashes::hex::Error),
+
+    /// Transaction not found
+    TransactionNotFound(Txid),
+    /// Header height not found
+    HeaderHeightNotFound(u32),
+    /// Header hash not found
+    HeaderHashNotFound(BlockHash),
+}
+
+impl fmt::Display for EsploraError {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        write!(f, "{:?}", self)
+    }
+}
+
+impl std::error::Error for EsploraError {}
+
+#[cfg(feature = "ureq")]
+impl_error!(::ureq::Error, Ureq, EsploraError);
+#[cfg(feature = "ureq")]
+impl_error!(::ureq::Transport, UreqTransport, EsploraError);
+#[cfg(feature = "reqwest")]
+impl_error!(::reqwest::Error, Reqwest, EsploraError);
+impl_error!(io::Error, Io, EsploraError);
+impl_error!(std::num::ParseIntError, Parsing, EsploraError);
+impl_error!(consensus::encode::Error, BitcoinEncoding, EsploraError);
+impl_error!(bitcoin::hashes::hex::Error, Hex, EsploraError);
+
+#[cfg(test)]
+#[cfg(feature = "test-esplora")]
+crate::bdk_blockchain_tests! {
+    fn test_instance(test_client: &TestClient) -> EsploraBlockchain {
+        EsploraBlockchain::new(&format!("http://{}",test_client.electrsd.esplora_url.as_ref().unwrap()), 20)
+    }
+}

src/blockchain/esplora/reqwest.rs

@@ -9,38 +9,25 @@
 // You may not use this file except in accordance with one or both of these
 // licenses.
 
-//! Esplora
-//!
-//! This module defines a [`Blockchain`] struct that can query an Esplora backend
-//! populate the wallet's [database](crate::database::Database) by
-//!
-//! ## Example
-//!
-//! ```no_run
-//! # use bdk::blockchain::esplora::EsploraBlockchain;
-//! let blockchain = EsploraBlockchain::new("https://blockstream.info/testnet/api", None);
-//! # Ok::<(), bdk::Error>(())
-//! ```
+//! Esplora by way of `reqwest` HTTP client.
 
 use std::collections::{HashMap, HashSet};
-use std::fmt;
 
-use futures::stream::{self, FuturesOrdered, StreamExt, TryStreamExt};
+use bitcoin::consensus::{deserialize, serialize};
+use bitcoin::hashes::hex::{FromHex, ToHex};
+use bitcoin::hashes::{sha256, Hash};
+use bitcoin::{BlockHeader, Script, Transaction, Txid};
 
 #[allow(unused_imports)]
 use log::{debug, error, info, trace};
 
-use serde::Deserialize;
+use futures::stream::{self, FuturesOrdered, StreamExt, TryStreamExt};
 
-use reqwest::{Client, StatusCode};
+use ::reqwest::{Client, StatusCode};
 
-use bitcoin::consensus::{self, deserialize, serialize};
-use bitcoin::hashes::hex::{FromHex, ToHex};
-use bitcoin::hashes::{sha256, Hash};
-use bitcoin::{BlockHash, BlockHeader, Script, Transaction, Txid};
-
-use self::utils::{ElectrumLikeSync, ElsGetHistoryRes};
-use super::*;
+use crate::blockchain::esplora::{EsploraError, EsploraGetHistory};
+use crate::blockchain::utils::{ElectrumLikeSync, ElsGetHistoryRes};
+use crate::blockchain::*;
 use crate::database::BatchDatabase;
 use crate::error::Error;
 use crate::wallet::utils::ChunksIterator;
@@ -62,22 +49,37 @@ struct UrlClient {
 /// ## Example
 /// See the [`blockchain::esplora`](crate::blockchain::esplora) module for a usage example.
 #[derive(Debug)]
-pub struct EsploraBlockchain(UrlClient);
+pub struct EsploraBlockchain {
+    url_client: UrlClient,
+    stop_gap: usize,
+}
 
 impl std::convert::From<UrlClient> for EsploraBlockchain {
     fn from(url_client: UrlClient) -> Self {
-        EsploraBlockchain(url_client)
+        EsploraBlockchain {
+            url_client,
+            stop_gap: 20,
+        }
     }
 }
 
 impl EsploraBlockchain {
-    /// Create a new instance of the client from a base URL
-    pub fn new(base_url: &str, concurrency: Option<u8>) -> Self {
-        EsploraBlockchain(UrlClient {
-            url: base_url.to_string(),
-            client: Client::new(),
-            concurrency: concurrency.unwrap_or(DEFAULT_CONCURRENT_REQUESTS),
-        })
+    /// Create a new instance of the client from a base URL and `stop_gap`.
+    pub fn new(base_url: &str, stop_gap: usize) -> Self {
+        EsploraBlockchain {
+            url_client: UrlClient {
+                url: base_url.to_string(),
+                client: Client::new(),
+                concurrency: DEFAULT_CONCURRENT_REQUESTS,
+            },
+            stop_gap,
+        }
+    }
+
+    /// Set the concurrency to use when doing batch queries against the Esplora instance.
+    pub fn with_concurrency(mut self, concurrency: u8) -> Self {
+        self.url_client.concurrency = concurrency;
+        self
     }
 }
 
@@ -95,42 +97,29 @@ impl Blockchain for EsploraBlockchain {
 
     fn setup<D: BatchDatabase, P: Progress>(
         &self,
-        stop_gap: Option<usize>,
         database: &mut D,
         progress_update: P,
     ) -> Result<(), Error> {
         maybe_await!(self
-            .0
-            .electrum_like_setup(stop_gap, database, progress_update))
+            .url_client
+            .electrum_like_setup(self.stop_gap, database, progress_update))
     }
 
     fn get_tx(&self, txid: &Txid) -> Result<Option<Transaction>, Error> {
-        Ok(await_or_block!(self.0._get_tx(txid))?)
+        Ok(await_or_block!(self.url_client._get_tx(txid))?)
     }
 
     fn broadcast(&self, tx: &Transaction) -> Result<(), Error> {
-        Ok(await_or_block!(self.0._broadcast(tx))?)
+        Ok(await_or_block!(self.url_client._broadcast(tx))?)
     }
 
     fn get_height(&self) -> Result<u32, Error> {
-        Ok(await_or_block!(self.0._get_height())?)
+        Ok(await_or_block!(self.url_client._get_height())?)
     }
 
     fn estimate_fee(&self, target: usize) -> Result<FeeRate, Error> {
-        let estimates = await_or_block!(self.0._get_fee_estimates())?;
-
-        let fee_val = estimates
-            .into_iter()
-            .map(|(k, v)| Ok::<_, std::num::ParseIntError>((k.parse::<usize>()?, v)))
-            .collect::<Result<Vec<_>, _>>()
-            .map_err(|e| Error::Generic(e.to_string()))?
-            .into_iter()
-            .take_while(|(k, _)| k <= &target)
-            .map(|(_, v)| v)
-            .last()
-            .unwrap_or(1.0);
-
-        Ok(FeeRate::from_sat_per_vb(fee_val as f32))
+        let estimates = await_or_block!(self.url_client._get_fee_estimates())?;
+        super::into_fee_rate(target, estimates)
     }
 }
 
@@ -292,74 +281,51 @@ impl ElectrumLikeSync for UrlClient {
         &self,
         scripts: I,
     ) -> Result<Vec<Vec<ElsGetHistoryRes>>, Error> {
-        let future = async {
-            let mut results = vec![];
-            for chunk in ChunksIterator::new(scripts.into_iter(), self.concurrency as usize) {
-                let mut futs = FuturesOrdered::new();
-                for script in chunk {
-                    futs.push(self._script_get_history(&script));
-                }
-                let partial_results: Vec<Vec<ElsGetHistoryRes>> = futs.try_collect().await?;
-                results.extend(partial_results);
+        let mut results = vec![];
+        for chunk in ChunksIterator::new(scripts.into_iter(), self.concurrency as usize) {
+            let mut futs = FuturesOrdered::new();
+            for script in chunk {
+                futs.push(self._script_get_history(script));
             }
-            Ok(stream::iter(results).collect().await)
-        };
-
-        await_or_block!(future)
+            let partial_results: Vec<Vec<ElsGetHistoryRes>> = await_or_block!(futs.try_collect())?;
+            results.extend(partial_results);
+        }
+        Ok(await_or_block!(stream::iter(results).collect()))
     }
 
     fn els_batch_transaction_get<'s, I: IntoIterator<Item = &'s Txid>>(
         &self,
         txids: I,
     ) -> Result<Vec<Transaction>, Error> {
-        let future = async {
-            let mut results = vec![];
-            for chunk in ChunksIterator::new(txids.into_iter(), self.concurrency as usize) {
-                let mut futs = FuturesOrdered::new();
-                for txid in chunk {
-                    futs.push(self._get_tx_no_opt(&txid));
-                }
-                let partial_results: Vec<Transaction> = futs.try_collect().await?;
-                results.extend(partial_results);
+        let mut results = vec![];
+        for chunk in ChunksIterator::new(txids.into_iter(), self.concurrency as usize) {
+            let mut futs = FuturesOrdered::new();
+            for txid in chunk {
+                futs.push(self._get_tx_no_opt(txid));
             }
-            Ok(stream::iter(results).collect().await)
-        };
-
-        await_or_block!(future)
+            let partial_results: Vec<Transaction> = await_or_block!(futs.try_collect())?;
+            results.extend(partial_results);
+        }
+        Ok(await_or_block!(stream::iter(results).collect()))
     }
 
     fn els_batch_block_header<I: IntoIterator<Item = u32>>(
         &self,
         heights: I,
     ) -> Result<Vec<BlockHeader>, Error> {
-        let future = async {
-            let mut results = vec![];
-            for chunk in ChunksIterator::new(heights.into_iter(), self.concurrency as usize) {
-                let mut futs = FuturesOrdered::new();
-                for height in chunk {
-                    futs.push(self._get_header(height));
-                }
-                let partial_results: Vec<BlockHeader> = futs.try_collect().await?;
-                results.extend(partial_results);
+        let mut results = vec![];
+        for chunk in ChunksIterator::new(heights.into_iter(), self.concurrency as usize) {
+            let mut futs = FuturesOrdered::new();
+            for height in chunk {
+                futs.push(self._get_header(height));
             }
-            Ok(stream::iter(results).collect().await)
-        };
-
-        await_or_block!(future)
+            let partial_results: Vec<BlockHeader> = await_or_block!(futs.try_collect())?;
+            results.extend(partial_results);
+        }
+        Ok(await_or_block!(stream::iter(results).collect()))
     }
 }
 
-#[derive(Deserialize)]
-struct EsploraGetHistoryStatus {
-    block_height: Option<usize>,
-}
-
-#[derive(Deserialize)]
-struct EsploraGetHistory {
-    txid: Txid,
-    status: EsploraGetHistoryStatus,
-}
-
 /// Configuration for an [`EsploraBlockchain`]
 #[derive(Debug, serde::Deserialize, serde::Serialize, Clone, PartialEq)]
 pub struct EsploraBlockchainConfig {
@@ -367,57 +333,40 @@ pub struct EsploraBlockchainConfig {
     ///
     /// eg. `https://blockstream.info/api/`
     pub base_url: String,
+    /// Optional URL of the proxy to use to make requests to the Esplora server
+    ///
+    /// The string should be formatted as: `<protocol>://<user>:<password>@host:<port>`.
+    ///
+    /// Note that the format of this value and the supported protocols change slightly between the
+    /// sync version of esplora (using `ureq`) and the async version (using `reqwest`). For more
+    /// details check with the documentation of the two crates. Both of them are compiled with
+    /// the `socks` feature enabled.
+    ///
+    /// The proxy is ignored when targeting `wasm32`.
+    pub proxy: Option<String>,
     /// Number of parallel requests sent to the esplora service (default: 4)
     pub concurrency: Option<u8>,
+    /// Stop searching addresses for transactions after finding an unused gap of this length.
+    pub stop_gap: usize,
 }
 
 impl ConfigurableBlockchain for EsploraBlockchain {
     type Config = EsploraBlockchainConfig;
 
     fn from_config(config: &Self::Config) -> Result<Self, Error> {
-        Ok(EsploraBlockchain::new(
-            config.base_url.as_str(),
-            config.concurrency,
-        ))
-    }
-}
-
-/// Errors that can happen during a sync with [`EsploraBlockchain`]
-#[derive(Debug)]
-pub enum EsploraError {
-    /// Error with the HTTP call
-    Reqwest(reqwest::Error),
-    /// Invalid number returned
-    Parsing(std::num::ParseIntError),
-    /// Invalid Bitcoin data returned
-    BitcoinEncoding(bitcoin::consensus::encode::Error),
-    /// Invalid Hex data returned
-    Hex(bitcoin::hashes::hex::Error),
-
-    /// Transaction not found
-    TransactionNotFound(Txid),
-    /// Header height not found
-    HeaderHeightNotFound(u32),
-    /// Header hash not found
-    HeaderHashNotFound(BlockHash),
-}
-
-impl fmt::Display for EsploraError {
-    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        write!(f, "{:?}", self)
-    }
-}
-
-impl std::error::Error for EsploraError {}
-
-impl_error!(reqwest::Error, Reqwest, EsploraError);
-impl_error!(std::num::ParseIntError, Parsing, EsploraError);
-impl_error!(consensus::encode::Error, BitcoinEncoding, EsploraError);
-impl_error!(bitcoin::hashes::hex::Error, Hex, EsploraError);
-
-#[cfg(feature = "test-blockchains")]
-crate::bdk_blockchain_tests! {
-    fn test_instance() -> EsploraBlockchain {
-        EsploraBlockchain::new(std::env::var("BDK_ESPLORA_URL").unwrap_or("127.0.0.1:3002".into()).as_str(), None)
+        let map_e = |e: reqwest::Error| Error::Esplora(Box::new(e.into()));
+
+        let mut blockchain = EsploraBlockchain::new(config.base_url.as_str(), config.stop_gap);
+        if let Some(concurrency) = config.concurrency {
+            blockchain.url_client.concurrency = concurrency;
+        }
+        #[cfg(not(target_arch = "wasm32"))]
+        if let Some(proxy) = &config.proxy {
+            blockchain.url_client.client = Client::builder()
+                .proxy(reqwest::Proxy::all(proxy).map_err(map_e)?)
+                .build()
+                .map_err(map_e)?;
+        }
+        Ok(blockchain)
     }
 }

src/blockchain/esplora/ureq.rs

@@ -0,0 +1,398 @@
+// Bitcoin Dev Kit
+// Written in 2020 by Alekos Filini <alekos.filini@gmail.com>
+//
+// Copyright (c) 2020-2021 Bitcoin Dev Kit Developers
+//
+// This file is licensed under the Apache License, Version 2.0 <LICENSE-APACHE
+// or http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your option.
+// You may not use this file except in accordance with one or both of these
+// licenses.
+
+//! Esplora by way of `ureq` HTTP client.
+
+use std::collections::{HashMap, HashSet};
+use std::io;
+use std::io::Read;
+use std::time::Duration;
+
+#[allow(unused_imports)]
+use log::{debug, error, info, trace};
+
+use ureq::{Agent, Proxy, Response};
+
+use bitcoin::consensus::{deserialize, serialize};
+use bitcoin::hashes::hex::{FromHex, ToHex};
+use bitcoin::hashes::{sha256, Hash};
+use bitcoin::{BlockHeader, Script, Transaction, Txid};
+
+use crate::blockchain::esplora::{EsploraError, EsploraGetHistory};
+use crate::blockchain::utils::{ElectrumLikeSync, ElsGetHistoryRes};
+use crate::blockchain::*;
+use crate::database::BatchDatabase;
+use crate::error::Error;
+use crate::FeeRate;
+
+#[derive(Debug)]
+struct UrlClient {
+    url: String,
+    agent: Agent,
+}
+
+/// Structure that implements the logic to sync with Esplora
+///
+/// ## Example
+/// See the [`blockchain::esplora`](crate::blockchain::esplora) module for a usage example.
+#[derive(Debug)]
+pub struct EsploraBlockchain {
+    url_client: UrlClient,
+    stop_gap: usize,
+}
+
+impl std::convert::From<UrlClient> for EsploraBlockchain {
+    fn from(url_client: UrlClient) -> Self {
+        EsploraBlockchain {
+            url_client,
+            stop_gap: 20,
+        }
+    }
+}
+
+impl EsploraBlockchain {
+    /// Create a new instance of the client from a base URL and the `stop_gap`.
+    pub fn new(base_url: &str, stop_gap: usize) -> Self {
+        EsploraBlockchain {
+            url_client: UrlClient {
+                url: base_url.to_string(),
+                agent: Agent::new(),
+            },
+            stop_gap,
+        }
+    }
+
+    /// Set the inner `ureq` agent.
+    pub fn with_agent(mut self, agent: Agent) -> Self {
+        self.url_client.agent = agent;
+        self
+    }
+}
+
+impl Blockchain for EsploraBlockchain {
+    fn get_capabilities(&self) -> HashSet<Capability> {
+        vec![
+            Capability::FullHistory,
+            Capability::GetAnyTx,
+            Capability::AccurateFees,
+        ]
+        .into_iter()
+        .collect()
+    }
+
+    fn setup<D: BatchDatabase, P: Progress>(
+        &self,
+        database: &mut D,
+        progress_update: P,
+    ) -> Result<(), Error> {
+        self.url_client
+            .electrum_like_setup(self.stop_gap, database, progress_update)
+    }
+
+    fn get_tx(&self, txid: &Txid) -> Result<Option<Transaction>, Error> {
+        Ok(self.url_client._get_tx(txid)?)
+    }
+
+    fn broadcast(&self, tx: &Transaction) -> Result<(), Error> {
+        let _txid = self.url_client._broadcast(tx)?;
+        Ok(())
+    }
+
+    fn get_height(&self) -> Result<u32, Error> {
+        Ok(self.url_client._get_height()?)
+    }
+
+    fn estimate_fee(&self, target: usize) -> Result<FeeRate, Error> {
+        let estimates = self.url_client._get_fee_estimates()?;
+        super::into_fee_rate(target, estimates)
+    }
+}
+
+impl UrlClient {
+    fn script_to_scripthash(script: &Script) -> String {
+        sha256::Hash::hash(script.as_bytes()).into_inner().to_hex()
+    }
+
+    fn _get_tx(&self, txid: &Txid) -> Result<Option<Transaction>, EsploraError> {
+        let resp = self
+            .agent
+            .get(&format!("{}/tx/{}/raw", self.url, txid))
+            .call();
+
+        match resp {
+            Ok(resp) => Ok(Some(deserialize(&into_bytes(resp)?)?)),
+            Err(ureq::Error::Status(code, _)) => {
+                if is_status_not_found(code) {
+                    return Ok(None);
+                }
+                Err(EsploraError::HttpResponse(code))
+            }
+            Err(e) => Err(EsploraError::Ureq(e)),
+        }
+    }
+
+    fn _get_tx_no_opt(&self, txid: &Txid) -> Result<Transaction, EsploraError> {
+        match self._get_tx(txid) {
+            Ok(Some(tx)) => Ok(tx),
+            Ok(None) => Err(EsploraError::TransactionNotFound(*txid)),
+            Err(e) => Err(e),
+        }
+    }
+
+    fn _get_header(&self, block_height: u32) -> Result<BlockHeader, EsploraError> {
+        let resp = self
+            .agent
+            .get(&format!("{}/block-height/{}", self.url, block_height))
+            .call();
+
+        let bytes = match resp {
+            Ok(resp) => Ok(into_bytes(resp)?),
+            Err(ureq::Error::Status(code, _)) => Err(EsploraError::HttpResponse(code)),
+            Err(e) => Err(EsploraError::Ureq(e)),
+        }?;
+
+        let hash = std::str::from_utf8(&bytes)
+            .map_err(|_| EsploraError::HeaderHeightNotFound(block_height))?;
+
+        let resp = self
+            .agent
+            .get(&format!("{}/block/{}/header", self.url, hash))
+            .call();
+
+        match resp {
+            Ok(resp) => Ok(deserialize(&Vec::from_hex(&resp.into_string()?)?)?),
+            Err(ureq::Error::Status(code, _)) => Err(EsploraError::HttpResponse(code)),
+            Err(e) => Err(EsploraError::Ureq(e)),
+        }
+    }
+
+    fn _broadcast(&self, transaction: &Transaction) -> Result<(), EsploraError> {
+        let resp = self
+            .agent
+            .post(&format!("{}/tx", self.url))
+            .send_string(&serialize(transaction).to_hex());
+
+        match resp {
+            Ok(_) => Ok(()), // We do not return the txid?
+            Err(ureq::Error::Status(code, _)) => Err(EsploraError::HttpResponse(code)),
+            Err(e) => Err(EsploraError::Ureq(e)),
+        }
+    }
+
+    fn _get_height(&self) -> Result<u32, EsploraError> {
+        let resp = self
+            .agent
+            .get(&format!("{}/blocks/tip/height", self.url))
+            .call();
+
+        match resp {
+            Ok(resp) => Ok(resp.into_string()?.parse()?),
+            Err(ureq::Error::Status(code, _)) => Err(EsploraError::HttpResponse(code)),
+            Err(e) => Err(EsploraError::Ureq(e)),
+        }
+    }
+
+    fn _script_get_history(&self, script: &Script) -> Result<Vec<ElsGetHistoryRes>, EsploraError> {
+        let mut result = Vec::new();
+        let scripthash = Self::script_to_scripthash(script);
+
+        // Add the unconfirmed transactions first
+
+        let resp = self
+            .agent
+            .get(&format!(
+                "{}/scripthash/{}/txs/mempool",
+                self.url, scripthash
+            ))
+            .call();
+
+        let v = match resp {
+            Ok(resp) => {
+                let v: Vec<EsploraGetHistory> = resp.into_json()?;
+                Ok(v)
+            }
+            Err(ureq::Error::Status(code, _)) => Err(EsploraError::HttpResponse(code)),
+            Err(e) => Err(EsploraError::Ureq(e)),
+        }?;
+
+        result.extend(v.into_iter().map(|x| ElsGetHistoryRes {
+            tx_hash: x.txid,
+            height: x.status.block_height.unwrap_or(0) as i32,
+        }));
+
+        debug!(
+            "Found {} mempool txs for {} - {:?}",
+            result.len(),
+            scripthash,
+            script
+        );
+
+        // Then go through all the pages of confirmed transactions
+        let mut last_txid = String::new();
+        loop {
+            let resp = self
+                .agent
+                .get(&format!(
+                    "{}/scripthash/{}/txs/chain/{}",
+                    self.url, scripthash, last_txid
+                ))
+                .call();
+
+            let v = match resp {
+                Ok(resp) => {
+                    let v: Vec<EsploraGetHistory> = resp.into_json()?;
+                    Ok(v)
+                }
+                Err(ureq::Error::Status(code, _)) => Err(EsploraError::HttpResponse(code)),
+                Err(e) => Err(EsploraError::Ureq(e)),
+            }?;
+
+            let len = v.len();
+            if let Some(elem) = v.last() {
+                last_txid = elem.txid.to_hex();
+            }
+
+            debug!("... adding {} confirmed transactions", len);
+
+            result.extend(v.into_iter().map(|x| ElsGetHistoryRes {
+                tx_hash: x.txid,
+                height: x.status.block_height.unwrap_or(0) as i32,
+            }));
+
+            if len < 25 {
+                break;
+            }
+        }
+
+        Ok(result)
+    }
+
+    fn _get_fee_estimates(&self) -> Result<HashMap<String, f64>, EsploraError> {
+        let resp = self
+            .agent
+            .get(&format!("{}/fee-estimates", self.url,))
+            .call();
+
+        let map = match resp {
+            Ok(resp) => {
+                let map: HashMap<String, f64> = resp.into_json()?;
+                Ok(map)
+            }
+            Err(ureq::Error::Status(code, _)) => Err(EsploraError::HttpResponse(code)),
+            Err(e) => Err(EsploraError::Ureq(e)),
+        }?;
+
+        Ok(map)
+    }
+}
+
+fn is_status_not_found(status: u16) -> bool {
+    status == 404
+}
+
+fn into_bytes(resp: Response) -> Result<Vec<u8>, io::Error> {
+    const BYTES_LIMIT: usize = 10 * 1_024 * 1_024;
+
+    let mut buf: Vec<u8> = vec![];
+    resp.into_reader()
+        .take((BYTES_LIMIT + 1) as u64)
+        .read_to_end(&mut buf)?;
+    if buf.len() > BYTES_LIMIT {
+        return Err(io::Error::new(
+            io::ErrorKind::Other,
+            "response too big for into_bytes",
+        ));
+    }
+
+    Ok(buf)
+}
+
+impl ElectrumLikeSync for UrlClient {
+    fn els_batch_script_get_history<'s, I: IntoIterator<Item = &'s Script>>(
+        &self,
+        scripts: I,
+    ) -> Result<Vec<Vec<ElsGetHistoryRes>>, Error> {
+        let mut results = vec![];
+        for script in scripts.into_iter() {
+            let v = self._script_get_history(script)?;
+            results.push(v);
+        }
+        Ok(results)
+    }
+
+    fn els_batch_transaction_get<'s, I: IntoIterator<Item = &'s Txid>>(
+        &self,
+        txids: I,
+    ) -> Result<Vec<Transaction>, Error> {
+        let mut results = vec![];
+        for txid in txids.into_iter() {
+            let tx = self._get_tx_no_opt(txid)?;
+            results.push(tx);
+        }
+        Ok(results)
+    }
+
+    fn els_batch_block_header<I: IntoIterator<Item = u32>>(
+        &self,
+        heights: I,
+    ) -> Result<Vec<BlockHeader>, Error> {
+        let mut results = vec![];
+        for height in heights.into_iter() {
+            let header = self._get_header(height)?;
+            results.push(header);
+        }
+        Ok(results)
+    }
+}
+
+/// Configuration for an [`EsploraBlockchain`]
+#[derive(Debug, serde::Deserialize, serde::Serialize, Clone, PartialEq)]
+pub struct EsploraBlockchainConfig {
+    /// Base URL of the esplora service eg. `https://blockstream.info/api/`
+    pub base_url: String,
+    /// Optional URL of the proxy to use to make requests to the Esplora server
+    ///
+    /// The string should be formatted as: `<protocol>://<user>:<password>@host:<port>`.
+    ///
+    /// Note that the format of this value and the supported protocols change slightly between the
+    /// sync version of esplora (using `ureq`) and the async version (using `reqwest`). For more
+    /// details check with the documentation of the two crates. Both of them are compiled with
+    /// the `socks` feature enabled.
+    ///
+    /// The proxy is ignored when targeting `wasm32`.
+    pub proxy: Option<String>,
+    /// Socket read timeout.
+    pub timeout_read: u64,
+    /// Socket write timeout.
+    pub timeout_write: u64,
+    /// Stop searching addresses for transactions after finding an unused gap of this length.
+    pub stop_gap: usize,
+}
+
+impl ConfigurableBlockchain for EsploraBlockchain {
+    type Config = EsploraBlockchainConfig;
+
+    fn from_config(config: &Self::Config) -> Result<Self, Error> {
+        let mut agent_builder = ureq::AgentBuilder::new()
+            .timeout_read(Duration::from_secs(config.timeout_read))
+            .timeout_write(Duration::from_secs(config.timeout_write));
+
+        if let Some(proxy) = &config.proxy {
+            agent_builder = agent_builder
+                .proxy(Proxy::new(proxy).map_err(|e| Error::Esplora(Box::new(e.into())))?);
+        }
+
+        Ok(
+            EsploraBlockchain::new(config.base_url.as_str(), config.stop_gap)
+                .with_agent(agent_builder.build()),
+        )
+    }
+}

src/blockchain/mod.rs

@@ -30,9 +30,19 @@ use crate::FeeRate;
 #[cfg(any(feature = "electrum", feature = "esplora"))]
 pub(crate) mod utils;
 
-#[cfg(any(feature = "electrum", feature = "esplora", feature = "compact_filters"))]
+#[cfg(any(
+    feature = "electrum",
+    feature = "esplora",
+    feature = "compact_filters",
+    feature = "rpc"
+))]
 pub mod any;
-#[cfg(any(feature = "electrum", feature = "esplora", feature = "compact_filters"))]
+#[cfg(any(
+    feature = "electrum",
+    feature = "esplora",
+    feature = "compact_filters",
+    feature = "rpc"
+))]
 pub use any::{AnyBlockchain, AnyBlockchainConfig};
 
 #[cfg(feature = "electrum")]
@@ -44,6 +54,7 @@ pub use self::electrum::ElectrumBlockchain;
 pub use self::electrum::ElectrumBlockchainConfig;
 
 #[cfg(feature = "rpc")]
+#[cfg_attr(docsrs, doc(cfg(feature = "rpc")))]
 pub mod rpc;
 #[cfg(feature = "rpc")]
 pub use self::rpc::RpcBlockchain;
@@ -92,7 +103,6 @@ pub trait Blockchain {
     /// [`Blockchain::sync`] defaults to calling this internally if not overridden.
     fn setup<D: BatchDatabase, P: 'static + Progress>(
         &self,
-        stop_gap: Option<usize>,
         database: &mut D,
         progress_update: P,
     ) -> Result<(), Error>;
@@ -117,11 +127,10 @@ pub trait Blockchain {
     /// [`BatchOperations::del_utxo`]: crate::database::BatchOperations::del_utxo
     fn sync<D: BatchDatabase, P: 'static + Progress>(
         &self,
-        stop_gap: Option<usize>,
         database: &mut D,
         progress_update: P,
     ) -> Result<(), Error> {
-        maybe_await!(self.setup(stop_gap, database, progress_update))
+        maybe_await!(self.setup(database, progress_update))
     }
 
     /// Fetch a transaction from the blockchain given its txid
@@ -192,7 +201,7 @@ impl Progress for NoopProgress {
 #[derive(Clone, Copy)]
 pub struct LogProgress;
 
-/// Create a nwe instance of [`LogProgress`]
+/// Create a new instance of [`LogProgress`]
 pub fn log_progress() -> LogProgress {
     LogProgress
 }
@@ -217,20 +226,18 @@ impl<T: Blockchain> Blockchain for Arc<T> {
 
     fn setup<D: BatchDatabase, P: 'static + Progress>(
         &self,
-        stop_gap: Option<usize>,
         database: &mut D,
         progress_update: P,
     ) -> Result<(), Error> {
-        maybe_await!(self.deref().setup(stop_gap, database, progress_update))
+        maybe_await!(self.deref().setup(database, progress_update))
     }
 
     fn sync<D: BatchDatabase, P: 'static + Progress>(
         &self,
-        stop_gap: Option<usize>,
         database: &mut D,
         progress_update: P,
     ) -> Result<(), Error> {
-        maybe_await!(self.deref().sync(stop_gap, database, progress_update))
+        maybe_await!(self.deref().sync(database, progress_update))
     }
 
     fn get_tx(&self, txid: &Txid) -> Result<Option<Transaction>, Error> {

src/blockchain/rpc.rs

@@ -13,13 +13,17 @@
 //!
 //! Backend that gets blockchain data from Bitcoin Core RPC
 //!
+//! This is an **EXPERIMENTAL** feature, API and other major changes are expected.
+//!
 //! ## Example
 //!
 //! ```no_run
-//! # use bdk::blockchain::{RpcConfig, RpcBlockchain, ConfigurableBlockchain};
+//! # use bdk::blockchain::{RpcConfig, RpcBlockchain, ConfigurableBlockchain, rpc::Auth};
 //! let config = RpcConfig {
 //!     url: "127.0.0.1:18332".to_string(),
-//!     auth: bitcoincore_rpc::Auth::CookieFile("/home/user/.bitcoin/.cookie".into()),
+//!     auth: Auth::Cookie {
+//!         file: "/home/user/.bitcoin/.cookie".into(),
+//!     },
 //!     network: bdk::bitcoin::Network::Testnet,
 //!     wallet_name: "wallet_name".to_string(),
 //!     skip_blocks: None,
@@ -39,10 +43,12 @@ use bitcoincore_rpc::json::{
     ImportMultiRequestScriptPubkey, ImportMultiRescanSince,
 };
 use bitcoincore_rpc::jsonrpc::serde_json::Value;
-use bitcoincore_rpc::{Auth, Client, RpcApi};
+use bitcoincore_rpc::Auth as RpcAuth;
+use bitcoincore_rpc::{Client, RpcApi};
 use log::debug;
-use serde::Deserialize;
+use serde::{Deserialize, Serialize};
 use std::collections::{HashMap, HashSet};
+use std::path::PathBuf;
 use std::str::FromStr;
 
 /// The main struct for RPC backend implementing the [crate::blockchain::Blockchain] trait
@@ -62,7 +68,7 @@ pub struct RpcBlockchain {
 }
 
 /// RpcBlockchain configuration options
-#[derive(Debug)]
+#[derive(Debug, Serialize, Deserialize, Clone, PartialEq)]
 pub struct RpcConfig {
     /// The bitcoin node url
     pub url: String,
@@ -76,6 +82,39 @@ pub struct RpcConfig {
     pub skip_blocks: Option<u32>,
 }
 
+/// This struct is equivalent to [bitcoincore_rpc::Auth] but it implements [serde::Serialize]
+/// To be removed once upstream equivalent is implementing Serialize (json serialization format
+/// should be the same), see [rust-bitcoincore-rpc/pull/181](https://github.com/rust-bitcoin/rust-bitcoincore-rpc/pull/181)
+#[derive(Clone, Debug, Hash, Eq, PartialEq, Ord, PartialOrd, Serialize, Deserialize)]
+#[serde(rename_all = "snake_case")]
+#[serde(untagged)]
+pub enum Auth {
+    /// None authentication
+    None,
+    /// Authentication with username and password, usually [Auth::Cookie] should be preferred
+    UserPass {
+        /// Username
+        username: String,
+        /// Password
+        password: String,
+    },
+    /// Authentication with a cookie file
+    Cookie {
+        /// Cookie file
+        file: PathBuf,
+    },
+}
+
+impl From<Auth> for RpcAuth {
+    fn from(auth: Auth) -> Self {
+        match auth {
+            Auth::None => RpcAuth::None,
+            Auth::UserPass { username, password } => RpcAuth::UserPass(username, password),
+            Auth::Cookie { file } => RpcAuth::CookieFile(file),
+        }
+    }
+}
+
 impl RpcBlockchain {
     fn get_node_synced_height(&self) -> Result<u32, Error> {
         let info = self.client.get_address_info(&self._storage_address)?;
@@ -104,7 +143,6 @@ impl Blockchain for RpcBlockchain {
 
     fn setup<D: BatchDatabase, P: 'static + Progress>(
         &self,
-        stop_gap: Option<usize>,
         database: &mut D,
         progress_update: P,
     ) -> Result<(), Error> {
@@ -118,7 +156,7 @@ impl Blockchain for RpcBlockchain {
             .iter()
             .map(|s| ImportMultiRequest {
                 timestamp: ImportMultiRescanSince::Timestamp(0),
-                script_pubkey: Some(ImportMultiRequestScriptPubkey::Script(&s)),
+                script_pubkey: Some(ImportMultiRequestScriptPubkey::Script(s)),
                 watchonly: Some(true),
                 ..Default::default()
             })
@@ -131,29 +169,31 @@ impl Blockchain for RpcBlockchain {
         //TODO maybe convenient using import_descriptor for compatible descriptor and import_multi as fallback
         self.client.import_multi(&requests, Some(&options))?;
 
-        let current_height = self.get_height()?;
+        loop {
+            let current_height = self.get_height()?;
 
-        // min because block invalidate may cause height to go down
-        let node_synced = self.get_node_synced_height()?.min(current_height);
+            // min because block invalidate may cause height to go down
+            let node_synced = self.get_node_synced_height()?.min(current_height);
 
-        //TODO call rescan in chunks (updating node_synced_height) so that in case of
-        // interruption work can be partially recovered
-        debug!(
-            "rescan_blockchain from:{} to:{}",
-            node_synced, current_height
-        );
-        self.client
-            .rescan_blockchain(Some(node_synced as usize), Some(current_height as usize))?;
-        progress_update.update(1.0, None)?;
+            let sync_up_to = node_synced.saturating_add(10_000).min(current_height);
 
-        self.set_node_synced_height(current_height)?;
+            debug!("rescan_blockchain from:{} to:{}", node_synced, sync_up_to);
+            self.client
+                .rescan_blockchain(Some(node_synced as usize), Some(sync_up_to as usize))?;
+            progress_update.update((sync_up_to as f32) / (current_height as f32), None)?;
 
-        self.sync(stop_gap, database, progress_update)
+            self.set_node_synced_height(sync_up_to)?;
+
+            if sync_up_to == current_height {
+                break;
+            }
+        }
+
+        self.sync(database, progress_update)
     }
 
     fn sync<D: BatchDatabase, P: 'static + Progress>(
         &self,
-        _stop_gap: Option<usize>,
         db: &mut D,
         _progress_update: P,
     ) -> Result<(), Error> {
@@ -198,7 +238,7 @@ impl Blockchain for RpcBlockchain {
                         txid, confirmation_time
                     );
                     known_tx.confirmation_time = confirmation_time;
-                    db.set_tx(&known_tx)?;
+                    db.set_tx(known_tx)?;
                 }
             } else {
                 //TODO check there is already the raw tx in db?
@@ -233,6 +273,7 @@ impl Blockchain for RpcBlockchain {
                     received,
                     sent,
                     fee: tx_result.fee.map(|f| f.as_sat().abs() as u64),
+                    verified: true,
                 };
                 debug!(
                     "saving tx: {} tx_result.fee:{:?} td.fees:{:?}",
@@ -319,7 +360,7 @@ impl ConfigurableBlockchain for RpcBlockchain {
         let wallet_url = format!("{}/wallet/{}", config.url, &wallet_name);
         debug!("connecting to {} auth:{:?}", wallet_url, config.auth);
 
-        let client = Client::new(wallet_url, config.auth.clone())?;
+        let client = Client::new(wallet_url.as_str(), config.auth.clone().into())?;
         let loaded_wallets = client.list_wallets()?;
         if loaded_wallets.contains(&wallet_name) {
             debug!("wallet already loaded {:?}", wallet_name);
@@ -386,13 +427,13 @@ where
 {
     //TODO check descriptors contains only public keys
     let descriptor = descriptor
-        .into_wallet_descriptor(&secp, network)?
+        .into_wallet_descriptor(secp, network)?
         .0
         .to_string();
     let mut wallet_name = get_checksum(&descriptor[..descriptor.find('#').unwrap()])?;
     if let Some(change_descriptor) = change_descriptor {
         let change_descriptor = change_descriptor
-            .into_wallet_descriptor(&secp, network)?
+            .into_wallet_descriptor(secp, network)?
             .0
             .to_string();
         wallet_name.push_str(
@@ -419,27 +460,14 @@ fn list_wallet_dir(client: &Client) -> Result<Vec<String>, Error> {
     Ok(result.wallets.into_iter().map(|n| n.name).collect())
 }
 
-#[cfg(feature = "test-blockchains")]
+#[cfg(test)]
+#[cfg(feature = "test-rpc")]
 crate::bdk_blockchain_tests! {
 
-    fn test_instance() -> RpcBlockchain {
-        let url = std::env::var("BDK_RPC_URL").unwrap_or_else(|_| "127.0.0.1:18443".to_string());
-        let url = format!("http://{}", url);
-
-        // TODO same code in `fn get_auth` in testutils, make it public there
-        let auth = match std::env::var("BDK_RPC_AUTH").as_ref().map(String::as_ref) {
-            Ok("USER_PASS") => Auth::UserPass(
-                std::env::var("BDK_RPC_USER").unwrap(),
-                std::env::var("BDK_RPC_PASS").unwrap(),
-            ),
-            _ => Auth::CookieFile(std::path::PathBuf::from(
-                std::env::var("BDK_RPC_COOKIEFILE")
-                    .unwrap_or_else(|_| "/home/user/.bitcoin/regtest/.cookie".to_string()),
-            )),
-        };
+    fn test_instance(test_client: &TestClient) -> RpcBlockchain {
         let config = RpcConfig {
-            url,
-            auth,
+            url: test_client.bitcoind.rpc_url(),
+            auth: Auth::Cookie { file: test_client.bitcoind.params.cookie_file.clone() },
             network: Network::Regtest,
             wallet_name: format!("client-wallet-test-{:?}", std::time::SystemTime::now() ),
             skip_blocks: None,
@@ -447,227 +475,3 @@ crate::bdk_blockchain_tests! {
         RpcBlockchain::from_config(&config).unwrap()
     }
 }
-
-#[cfg(feature = "test-rpc")]
-#[cfg(test)]
-mod test {
-    use super::{RpcBlockchain, RpcConfig};
-    use crate::bitcoin::consensus::deserialize;
-    use crate::bitcoin::{Address, Amount, Network, Transaction};
-    use crate::blockchain::rpc::wallet_name_from_descriptor;
-    use crate::blockchain::{noop_progress, Blockchain, Capability, ConfigurableBlockchain};
-    use crate::database::MemoryDatabase;
-    use crate::wallet::AddressIndex;
-    use crate::Wallet;
-    use bitcoin::secp256k1::Secp256k1;
-    use bitcoin::Txid;
-    use bitcoincore_rpc::json::CreateRawTransactionInput;
-    use bitcoincore_rpc::RawTx;
-    use bitcoincore_rpc::{Auth, RpcApi};
-    use bitcoind::BitcoinD;
-    use std::collections::HashMap;
-
-    fn create_rpc(
-        bitcoind: &BitcoinD,
-        desc: &str,
-        network: Network,
-    ) -> Result<RpcBlockchain, crate::Error> {
-        let secp = Secp256k1::new();
-        let wallet_name = wallet_name_from_descriptor(desc, None, network, &secp).unwrap();
-
-        let config = RpcConfig {
-            url: bitcoind.rpc_url(),
-            auth: Auth::CookieFile(bitcoind.config.cookie_file.clone()),
-            network,
-            wallet_name,
-            skip_blocks: None,
-        };
-        RpcBlockchain::from_config(&config)
-    }
-    fn create_bitcoind(args: Vec<String>) -> BitcoinD {
-        let exe = std::env::var("BITCOIND_EXE").unwrap();
-        bitcoind::BitcoinD::with_args(exe, args, false, bitcoind::P2P::No).unwrap()
-    }
-
-    const DESCRIPTOR_PUB: &'static str = "wpkh(tpubD6NzVbkrYhZ4X2yy78HWrr1M9NT8dKeWfzNiQqDdMqqa9UmmGztGGz6TaLFGsLfdft5iu32gxq1T4eMNxExNNWzVCpf9Y6JZi5TnqoC9wJq/*)";
-    const DESCRIPTOR_PRIV: &'static str = "wpkh(tprv8ZgxMBicQKsPdZxBDUcvTSMEaLwCTzTc6gmw8KBKwa3BJzWzec4g6VUbQBHJcutDH6mMEmBeVyN27H1NF3Nu8isZ1Sts4SufWyfLE6Mf1MB/*)";
-
-    #[test]
-    fn test_rpc_wallet_setup() {
-        env_logger::try_init().unwrap();
-        let bitcoind = create_bitcoind(vec![]);
-        let node_address = bitcoind.client.get_new_address(None, None).unwrap();
-        let blockchain = create_rpc(&bitcoind, DESCRIPTOR_PUB, Network::Regtest).unwrap();
-        let db = MemoryDatabase::new();
-        let wallet = Wallet::new(DESCRIPTOR_PRIV, None, Network::Regtest, db, blockchain).unwrap();
-
-        wallet.sync(noop_progress(), None).unwrap();
-        generate(&bitcoind, 101);
-        wallet.sync(noop_progress(), None).unwrap();
-        let address = wallet.get_address(AddressIndex::New).unwrap();
-        let expected_address = "bcrt1q8dyvgt4vhr8ald4xuwewcxhdjha9a5k78wxm5t";
-        assert_eq!(expected_address, address.to_string());
-        send_to_address(&bitcoind, &address, 100_000);
-        wallet.sync(noop_progress(), None).unwrap();
-        assert_eq!(wallet.get_balance().unwrap(), 100_000);
-
-        let mut builder = wallet.build_tx();
-        builder.add_recipient(node_address.script_pubkey(), 50_000);
-        let (mut psbt, details) = builder.finish().unwrap();
-        let finalized = wallet.sign(&mut psbt, Default::default()).unwrap();
-        assert!(finalized, "Cannot finalize transaction");
-        let tx = psbt.extract_tx();
-        wallet.broadcast(tx).unwrap();
-        wallet.sync(noop_progress(), None).unwrap();
-        assert_eq!(
-            wallet.get_balance().unwrap(),
-            100_000 - 50_000 - details.fee.unwrap_or(0)
-        );
-        drop(wallet);
-
-        // test skip_blocks
-        generate(&bitcoind, 5);
-        let config = RpcConfig {
-            url: bitcoind.rpc_url(),
-            auth: Auth::CookieFile(bitcoind.config.cookie_file.clone()),
-            network: Network::Regtest,
-            wallet_name: "another-name".to_string(),
-            skip_blocks: Some(103),
-        };
-        let blockchain_skip = RpcBlockchain::from_config(&config).unwrap();
-        let db = MemoryDatabase::new();
-        let wallet_skip =
-            Wallet::new(DESCRIPTOR_PRIV, None, Network::Regtest, db, blockchain_skip).unwrap();
-        wallet_skip.sync(noop_progress(), None).unwrap();
-        send_to_address(&bitcoind, &address, 100_000);
-        wallet_skip.sync(noop_progress(), None).unwrap();
-        assert_eq!(wallet_skip.get_balance().unwrap(), 100_000);
-    }
-
-    #[test]
-    fn test_rpc_from_config() {
-        let bitcoind = create_bitcoind(vec![]);
-        let blockchain = create_rpc(&bitcoind, DESCRIPTOR_PUB, Network::Regtest);
-        assert!(blockchain.is_ok());
-        let blockchain = create_rpc(&bitcoind, DESCRIPTOR_PUB, Network::Testnet);
-        assert!(blockchain.is_err(), "wrong network doesn't error");
-    }
-
-    #[test]
-    fn test_rpc_capabilities_get_tx() {
-        let bitcoind = create_bitcoind(vec![]);
-        let rpc = create_rpc(&bitcoind, DESCRIPTOR_PUB, Network::Regtest).unwrap();
-        let capabilities = rpc.get_capabilities();
-        assert!(capabilities.contains(&Capability::FullHistory) && capabilities.len() == 1);
-        let bitcoind_indexed = create_bitcoind(vec!["-txindex".to_string()]);
-        let rpc_indexed = create_rpc(&bitcoind_indexed, DESCRIPTOR_PUB, Network::Regtest).unwrap();
-        assert_eq!(rpc_indexed.get_capabilities().len(), 3);
-        let address = generate(&bitcoind_indexed, 101);
-        let txid = send_to_address(&bitcoind_indexed, &address, 100_000);
-        assert!(rpc_indexed.get_tx(&txid).unwrap().is_some());
-        assert!(rpc.get_tx(&txid).is_err());
-    }
-
-    #[test]
-    fn test_rpc_estimate_fee_get_height() {
-        let bitcoind = create_bitcoind(vec![]);
-        let rpc = create_rpc(&bitcoind, DESCRIPTOR_PUB, Network::Regtest).unwrap();
-        let result = rpc.estimate_fee(2);
-        assert!(result.is_err());
-        let address = generate(&bitcoind, 100);
-        // create enough tx so that core give some fee estimation
-        for _ in 0..15 {
-            let _ = bitcoind.client.generate_to_address(1, &address).unwrap();
-            for _ in 0..2 {
-                send_to_address(&bitcoind, &address, 100_000);
-            }
-        }
-        let result = rpc.estimate_fee(2);
-        assert!(result.is_ok());
-        assert_eq!(rpc.get_height().unwrap(), 115);
-    }
-
-    #[test]
-    fn test_rpc_node_synced_height() {
-        let bitcoind = create_bitcoind(vec![]);
-        let rpc = create_rpc(&bitcoind, DESCRIPTOR_PUB, Network::Regtest).unwrap();
-        let synced_height = rpc.get_node_synced_height().unwrap();
-
-        assert_eq!(synced_height, 0);
-        rpc.set_node_synced_height(1).unwrap();
-
-        let synced_height = rpc.get_node_synced_height().unwrap();
-        assert_eq!(synced_height, 1);
-    }
-
-    #[test]
-    fn test_rpc_broadcast() {
-        let bitcoind = create_bitcoind(vec![]);
-        let rpc = create_rpc(&bitcoind, DESCRIPTOR_PUB, Network::Regtest).unwrap();
-        let address = generate(&bitcoind, 101);
-        let utxo = bitcoind
-            .client
-            .list_unspent(None, None, None, None, None)
-            .unwrap();
-        let input = CreateRawTransactionInput {
-            txid: utxo[0].txid,
-            vout: utxo[0].vout,
-            sequence: None,
-        };
-
-        let out: HashMap<_, _> = vec![(
-            address.to_string(),
-            utxo[0].amount - Amount::from_sat(100_000),
-        )]
-        .into_iter()
-        .collect();
-        let tx = bitcoind
-            .client
-            .create_raw_transaction(&[input], &out, None, None)
-            .unwrap();
-        let signed_tx = bitcoind
-            .client
-            .sign_raw_transaction_with_wallet(tx.raw_hex(), None, None)
-            .unwrap();
-        let parsed_tx: Transaction = deserialize(&signed_tx.hex).unwrap();
-        rpc.broadcast(&parsed_tx).unwrap();
-        assert!(bitcoind
-            .client
-            .get_raw_mempool()
-            .unwrap()
-            .contains(&tx.txid()));
-    }
-
-    #[test]
-    fn test_rpc_wallet_name() {
-        let secp = Secp256k1::new();
-        let name =
-            wallet_name_from_descriptor(DESCRIPTOR_PUB, None, Network::Regtest, &secp).unwrap();
-        assert_eq!("tmg7aqay", name);
-    }
-
-    fn generate(bitcoind: &BitcoinD, blocks: u64) -> Address {
-        let address = bitcoind.client.get_new_address(None, None).unwrap();
-        bitcoind
-            .client
-            .generate_to_address(blocks, &address)
-            .unwrap();
-        address
-    }
-
-    fn send_to_address(bitcoind: &BitcoinD, address: &Address, amount: u64) -> Txid {
-        bitcoind
-            .client
-            .send_to_address(
-                &address,
-                Amount::from_sat(amount),
-                None,
-                None,
-                None,
-                None,
-                None,
-                None,
-            )
-            .unwrap()
-    }
-}

src/blockchain/utils.rs

@@ -53,7 +53,7 @@ pub trait ElectrumLikeSync {
 
     fn electrum_like_setup<D: BatchDatabase, P: Progress>(
         &self,
-        stop_gap: Option<usize>,
+        stop_gap: usize,
         db: &mut D,
         _progress_update: P,
     ) -> Result<(), Error> {
@@ -61,7 +61,6 @@ pub trait ElectrumLikeSync {
         let start = Instant::new();
         debug!("start setup");
 
-        let stop_gap = stop_gap.unwrap_or(20);
         let chunk_size = stop_gap;
 
         let mut history_txs_id = HashSet::new();
@@ -362,6 +361,7 @@ fn save_transaction_details_and_utxos<D: BatchDatabase>(
         sent: outgoing,
         confirmation_time: ConfirmationTime::new(height, timestamp),
         fee: Some(inputs_sum.saturating_sub(outputs_sum)), /* if the tx is a coinbase, fees would be negative */
+        verified: height.is_some(),
     };
     updates.set_tx(&tx_details)?;
 
@@ -369,7 +369,7 @@ fn save_transaction_details_and_utxos<D: BatchDatabase>(
 }
 
 /// returns utxo dependency as the inputs needed for the utxo to exist
-/// `tx_raw_in_db` must contains utxo's generating txs or errors witt [crate::Error::TransactionNotFound]
+/// `tx_raw_in_db` must contains utxo's generating txs or errors with [crate::Error::TransactionNotFound]
 fn utxos_deps<D: BatchDatabase>(
     db: &mut D,
     tx_raw_in_db: &HashMap<Txid, Transaction>,

src/database/any.rs

@@ -65,6 +65,8 @@ macro_rules! impl_inner_method {
             $enum_name::Memory(inner) => inner.$name( $($args, )* ),
             #[cfg(feature = "key-value-db")]
             $enum_name::Sled(inner) => inner.$name( $($args, )* ),
+            #[cfg(feature = "sqlite")]
+            $enum_name::Sqlite(inner) => inner.$name( $($args, )* ),
         }
     }
 }
@@ -82,10 +84,15 @@ pub enum AnyDatabase {
     #[cfg_attr(docsrs, doc(cfg(feature = "key-value-db")))]
     /// Simple key-value embedded database based on [`sled`]
     Sled(sled::Tree),
+    #[cfg(feature = "sqlite")]
+    #[cfg_attr(docsrs, doc(cfg(feature = "sqlite")))]
+    /// Sqlite embedded database using [`rusqlite`]
+    Sqlite(sqlite::SqliteDatabase),
 }
 
 impl_from!(memory::MemoryDatabase, AnyDatabase, Memory,);
 impl_from!(sled::Tree, AnyDatabase, Sled, #[cfg(feature = "key-value-db")]);
+impl_from!(sqlite::SqliteDatabase, AnyDatabase, Sqlite, #[cfg(feature = "sqlite")]);
 
 /// Type that contains any of the [`BatchDatabase::Batch`] types defined by the library
 pub enum AnyBatch {
@@ -95,6 +102,10 @@ pub enum AnyBatch {
     #[cfg_attr(docsrs, doc(cfg(feature = "key-value-db")))]
     /// Simple key-value embedded database based on [`sled`]
     Sled(<sled::Tree as BatchDatabase>::Batch),
+    #[cfg(feature = "sqlite")]
+    #[cfg_attr(docsrs, doc(cfg(feature = "sqlite")))]
+    /// Sqlite embedded database using [`rusqlite`]
+    Sqlite(<sqlite::SqliteDatabase as BatchDatabase>::Batch),
 }
 
 impl_from!(
@@ -103,6 +114,7 @@ impl_from!(
     Memory,
 );
 impl_from!(<sled::Tree as BatchDatabase>::Batch, AnyBatch, Sled, #[cfg(feature = "key-value-db")]);
+impl_from!(<sqlite::SqliteDatabase as BatchDatabase>::Batch, AnyBatch, Sqlite, #[cfg(feature = "sqlite")]);
 
 impl BatchOperations for AnyDatabase {
     fn set_script_pubkey(
@@ -233,6 +245,10 @@ impl Database for AnyDatabase {
     fn increment_last_index(&mut self, keychain: KeychainKind) -> Result<u32, Error> {
         impl_inner_method!(AnyDatabase, self, increment_last_index, keychain)
     }
+
+    fn flush(&mut self) -> Result<(), Error> {
+        impl_inner_method!(AnyDatabase, self, flush)
+    }
 }
 
 impl BatchOperations for AnyBatch {
@@ -296,19 +312,26 @@ impl BatchDatabase for AnyDatabase {
             AnyDatabase::Memory(inner) => inner.begin_batch().into(),
             #[cfg(feature = "key-value-db")]
             AnyDatabase::Sled(inner) => inner.begin_batch().into(),
+            #[cfg(feature = "sqlite")]
+            AnyDatabase::Sqlite(inner) => inner.begin_batch().into(),
         }
     }
     fn commit_batch(&mut self, batch: Self::Batch) -> Result<(), Error> {
         match self {
             AnyDatabase::Memory(db) => match batch {
                 AnyBatch::Memory(batch) => db.commit_batch(batch),
-                #[cfg(feature = "key-value-db")]
-                _ => unimplemented!("Sled batch shouldn't be used with Memory db."),
+                #[cfg(any(feature = "key-value-db", feature = "sqlite"))]
+                _ => unimplemented!("Other batch shouldn't be used with Memory db."),
             },
             #[cfg(feature = "key-value-db")]
             AnyDatabase::Sled(db) => match batch {
                 AnyBatch::Sled(batch) => db.commit_batch(batch),
-                _ => unimplemented!("Memory batch shouldn't be used with Sled db."),
+                _ => unimplemented!("Other batch shouldn't be used with Sled db."),
+            },
+            #[cfg(feature = "sqlite")]
+            AnyDatabase::Sqlite(db) => match batch {
+                AnyBatch::Sqlite(batch) => db.commit_batch(batch),
+                _ => unimplemented!("Other batch shouldn't be used with Sqlite db."),
             },
         }
     }
@@ -333,6 +356,23 @@ impl ConfigurableDatabase for sled::Tree {
     }
 }
 
+/// Configuration type for a [`sqlite::SqliteDatabase`] database
+#[cfg(feature = "sqlite")]
+#[derive(Debug, serde::Serialize, serde::Deserialize)]
+pub struct SqliteDbConfiguration {
+    /// Main directory of the db
+    pub path: String,
+}
+
+#[cfg(feature = "sqlite")]
+impl ConfigurableDatabase for sqlite::SqliteDatabase {
+    type Config = SqliteDbConfiguration;
+
+    fn from_config(config: &Self::Config) -> Result<Self, Error> {
+        Ok(sqlite::SqliteDatabase::new(config.path.clone()))
+    }
+}
+
 /// Type that can contain any of the database configurations defined by the library
 ///
 /// This allows storing a single configuration that can be loaded into an [`AnyDatabase`]
@@ -346,6 +386,10 @@ pub enum AnyDatabaseConfig {
     #[cfg_attr(docsrs, doc(cfg(feature = "key-value-db")))]
     /// Simple key-value embedded database based on [`sled`]
     Sled(SledDbConfiguration),
+    #[cfg(feature = "sqlite")]
+    #[cfg_attr(docsrs, doc(cfg(feature = "sqlite")))]
+    /// Sqlite embedded database using [`rusqlite`]
+    Sqlite(SqliteDbConfiguration),
 }
 
 impl ConfigurableDatabase for AnyDatabase {
@@ -358,9 +402,14 @@ impl ConfigurableDatabase for AnyDatabase {
             }
             #[cfg(feature = "key-value-db")]
             AnyDatabaseConfig::Sled(inner) => AnyDatabase::Sled(sled::Tree::from_config(inner)?),
+            #[cfg(feature = "sqlite")]
+            AnyDatabaseConfig::Sqlite(inner) => {
+                AnyDatabase::Sqlite(sqlite::SqliteDatabase::from_config(inner)?)
+            }
         })
     }
 }
 
 impl_from!((), AnyDatabaseConfig, Memory,);
 impl_from!(SledDbConfiguration, AnyDatabaseConfig, Sled, #[cfg(feature = "key-value-db")]);
+impl_from!(SqliteDbConfiguration, AnyDatabaseConfig, Sqlite, #[cfg(feature = "sqlite")]);

src/database/keyvalue.rs

@@ -367,6 +367,10 @@ impl Database for Tree {
             Ok(val)
         })
     }
+
+    fn flush(&mut self) -> Result<(), Error> {
+        Ok(Tree::flush(self).map(|_| ())?)
+    }
 }
 
 impl BatchDatabase for Tree {
@@ -383,6 +387,7 @@ impl BatchDatabase for Tree {
 
 #[cfg(test)]
 mod test {
+    use lazy_static::lazy_static;
     use std::sync::{Arc, Condvar, Mutex, Once};
     use std::time::{SystemTime, UNIX_EPOCH};
 

src/database/memory.rs

@@ -14,6 +14,7 @@
 //! This module defines an in-memory database type called [`MemoryDatabase`] that is based on a
 //! [`BTreeMap`].
 
+use std::any::Any;
 use std::collections::BTreeMap;
 use std::ops::Bound::{Excluded, Included};
 
@@ -110,7 +111,7 @@ fn after(key: &[u8]) -> Vec<u8> {
 /// [`database`]: crate::database
 #[derive(Debug, Default)]
 pub struct MemoryDatabase {
-    map: BTreeMap<Vec<u8>, Box<dyn std::any::Any>>,
+    map: BTreeMap<Vec<u8>, Box<dyn Any + Send + Sync>>,
     deleted_keys: Vec<Vec<u8>>,
 }
 
@@ -419,6 +420,10 @@ impl Database for MemoryDatabase {
 
         Ok(*value)
     }
+
+    fn flush(&mut self) -> Result<(), Error> {
+        Ok(())
+    }
 }
 
 impl BatchDatabase for MemoryDatabase {
@@ -452,20 +457,21 @@ impl ConfigurableDatabase for MemoryDatabase {
 /// don't have `test` set.
 macro_rules! populate_test_db {
     ($db:expr, $tx_meta:expr, $current_height:expr$(,)?) => {{
+        use std::str::FromStr;
         use $crate::database::BatchOperations;
         let mut db = $db;
         let tx_meta = $tx_meta;
         let current_height: Option<u32> = $current_height;
-        let tx = Transaction {
+        let tx = $crate::bitcoin::Transaction {
             version: 1,
             lock_time: 0,
             input: vec![],
             output: tx_meta
                 .output
                 .iter()
-                .map(|out_meta| bitcoin::TxOut {
+                .map(|out_meta| $crate::bitcoin::TxOut {
                     value: out_meta.value,
-                    script_pubkey: bitcoin::Address::from_str(&out_meta.to_address)
+                    script_pubkey: $crate::bitcoin::Address::from_str(&out_meta.to_address)
                         .unwrap()
                         .script_pubkey(),
                 })
@@ -473,29 +479,32 @@ macro_rules! populate_test_db {
         };
 
         let txid = tx.txid();
-        let confirmation_time = tx_meta.min_confirmations.map(|conf| ConfirmationTime {
-            height: current_height.unwrap().checked_sub(conf as u32).unwrap(),
-            timestamp: 0,
-        });
+        let confirmation_time = tx_meta
+            .min_confirmations
+            .map(|conf| $crate::ConfirmationTime {
+                height: current_height.unwrap().checked_sub(conf as u32).unwrap(),
+                timestamp: 0,
+            });
 
-        let tx_details = TransactionDetails {
+        let tx_details = $crate::TransactionDetails {
             transaction: Some(tx.clone()),
             txid,
             fee: Some(0),
             received: 0,
             sent: 0,
             confirmation_time,
+            verified: current_height.is_some(),
         };
 
         db.set_tx(&tx_details).unwrap();
         for (vout, out) in tx.output.iter().enumerate() {
-            db.set_utxo(&LocalUtxo {
+            db.set_utxo(&$crate::LocalUtxo {
                 txout: out.clone(),
-                outpoint: OutPoint {
+                outpoint: $crate::bitcoin::OutPoint {
                     txid,
                     vout: vout as u32,
                 },
-                keychain: KeychainKind::External,
+                keychain: $crate::KeychainKind::External,
             })
             .unwrap();
         }

src/database/mod.rs

@@ -36,6 +36,11 @@ pub use any::{AnyDatabase, AnyDatabaseConfig};
 #[cfg(feature = "key-value-db")]
 pub(crate) mod keyvalue;
 
+#[cfg(feature = "sqlite")]
+pub(crate) mod sqlite;
+#[cfg(feature = "sqlite")]
+pub use sqlite::SqliteDatabase;
+
 pub mod memory;
 pub use memory::MemoryDatabase;
 
@@ -134,6 +139,9 @@ pub trait Database: BatchOperations {
     ///
     /// It should insert and return `0` if not present in the database
     fn increment_last_index(&mut self, keychain: KeychainKind) -> Result<u32, Error>;
+
+    /// Force changes to be written to disk
+    fn flush(&mut self) -> Result<(), Error>;
 }
 
 /// Trait for a database that supports batch operations
@@ -321,6 +329,7 @@ pub mod test {
                 timestamp: 123456,
                 height: 1000,
             }),
+            verified: true,
         };
 
         tree.set_tx(&tx_details).unwrap();

src/database/sqlite.rs

@@ -0,0 +1,968 @@
+// Bitcoin Dev Kit
+// Written in 2020 by Alekos Filini <alekos.filini@gmail.com>
+//
+// Copyright (c) 2020-2021 Bitcoin Dev Kit Developers
+//
+// This file is licensed under the Apache License, Version 2.0 <LICENSE-APACHE
+// or http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your option.
+// You may not use this file except in accordance with one or both of these
+// licenses.
+
+use bitcoin::consensus::encode::{deserialize, serialize};
+use bitcoin::hash_types::Txid;
+use bitcoin::{OutPoint, Script, Transaction, TxOut};
+
+use crate::database::{BatchDatabase, BatchOperations, Database};
+use crate::error::Error;
+use crate::types::*;
+
+use rusqlite::{named_params, Connection};
+
+static MIGRATIONS: &[&str] = &[
+    "CREATE TABLE version (version INTEGER)",
+    "INSERT INTO version VALUES (1)",
+    "CREATE TABLE script_pubkeys (keychain TEXT, child INTEGER, script BLOB);",
+    "CREATE INDEX idx_keychain_child ON script_pubkeys(keychain, child);",
+    "CREATE INDEX idx_script ON script_pubkeys(script);",
+    "CREATE TABLE utxos (value INTEGER, keychain TEXT, vout INTEGER, txid BLOB, script BLOB);",
+    "CREATE INDEX idx_txid_vout ON utxos(txid, vout);",
+    "CREATE TABLE transactions (txid BLOB, raw_tx BLOB);",
+    "CREATE INDEX idx_txid ON transactions(txid);",
+    "CREATE TABLE transaction_details (txid BLOB, timestamp INTEGER, received INTEGER, sent INTEGER, fee INTEGER, height INTEGER, verified INTEGER DEFAULT 0);",
+    "CREATE INDEX idx_txdetails_txid ON transaction_details(txid);",
+    "CREATE TABLE last_derivation_indices (keychain TEXT, value INTEGER);",
+    "CREATE UNIQUE INDEX idx_indices_keychain ON last_derivation_indices(keychain);",
+    "CREATE TABLE checksums (keychain TEXT, checksum BLOB);",
+    "CREATE INDEX idx_checksums_keychain ON checksums(keychain);",
+];
+
+/// Sqlite database stored on filesystem
+///
+/// This is a permanent storage solution for devices and platforms that provide a filesystem.
+/// [`crate::database`]
+#[derive(Debug)]
+pub struct SqliteDatabase {
+    /// Path on the local filesystem to store the sqlite file
+    pub path: String,
+    /// A rusqlite connection object to the sqlite database
+    pub connection: Connection,
+}
+
+impl SqliteDatabase {
+    /// Instantiate a new SqliteDatabase instance by creating a connection
+    /// to the database stored at path
+    pub fn new(path: String) -> Self {
+        let connection = get_connection(&path).unwrap();
+        SqliteDatabase { path, connection }
+    }
+    fn insert_script_pubkey(
+        &self,
+        keychain: String,
+        child: u32,
+        script: &[u8],
+    ) -> Result<i64, Error> {
+        let mut statement = self.connection.prepare_cached("INSERT INTO script_pubkeys (keychain, child, script) VALUES (:keychain, :child, :script)")?;
+        statement.execute(named_params! {
+            ":keychain": keychain,
+            ":child": child,
+            ":script": script
+        })?;
+
+        Ok(self.connection.last_insert_rowid())
+    }
+    fn insert_utxo(
+        &self,
+        value: u64,
+        keychain: String,
+        vout: u32,
+        txid: &[u8],
+        script: &[u8],
+    ) -> Result<i64, Error> {
+        let mut statement = self.connection.prepare_cached("INSERT INTO utxos (value, keychain, vout, txid, script) VALUES (:value, :keychain, :vout, :txid, :script)")?;
+        statement.execute(named_params! {
+            ":value": value,
+            ":keychain": keychain,
+            ":vout": vout,
+            ":txid": txid,
+            ":script": script
+        })?;
+
+        Ok(self.connection.last_insert_rowid())
+    }
+    fn insert_transaction(&self, txid: &[u8], raw_tx: &[u8]) -> Result<i64, Error> {
+        let mut statement = self
+            .connection
+            .prepare_cached("INSERT INTO transactions (txid, raw_tx) VALUES (:txid, :raw_tx)")?;
+        statement.execute(named_params! {
+            ":txid": txid,
+            ":raw_tx": raw_tx,
+        })?;
+
+        Ok(self.connection.last_insert_rowid())
+    }
+
+    fn update_transaction(&self, txid: &[u8], raw_tx: &[u8]) -> Result<(), Error> {
+        let mut statement = self
+            .connection
+            .prepare_cached("UPDATE transactions SET raw_tx=:raw_tx WHERE txid=:txid")?;
+
+        statement.execute(named_params! {
+            ":txid": txid,
+            ":raw_tx": raw_tx,
+        })?;
+
+        Ok(())
+    }
+
+    fn insert_transaction_details(&self, transaction: &TransactionDetails) -> Result<i64, Error> {
+        let (timestamp, height) = match &transaction.confirmation_time {
+            Some(confirmation_time) => (
+                Some(confirmation_time.timestamp),
+                Some(confirmation_time.height),
+            ),
+            None => (None, None),
+        };
+
+        let txid: &[u8] = &transaction.txid;
+
+        let mut statement = self.connection.prepare_cached("INSERT INTO transaction_details (txid, timestamp, received, sent, fee, height, verified) VALUES (:txid, :timestamp, :received, :sent, :fee, :height, :verified)")?;
+
+        statement.execute(named_params! {
+            ":txid": txid,
+            ":timestamp": timestamp,
+            ":received": transaction.received,
+            ":sent": transaction.sent,
+            ":fee": transaction.fee,
+            ":height": height,
+            ":verified": transaction.verified
+        })?;
+
+        Ok(self.connection.last_insert_rowid())
+    }
+
+    fn update_transaction_details(&self, transaction: &TransactionDetails) -> Result<(), Error> {
+        let (timestamp, height) = match &transaction.confirmation_time {
+            Some(confirmation_time) => (
+                Some(confirmation_time.timestamp),
+                Some(confirmation_time.height),
+            ),
+            None => (None, None),
+        };
+
+        let txid: &[u8] = &transaction.txid;
+
+        let mut statement = self.connection.prepare_cached("UPDATE transaction_details SET timestamp=:timestamp, received=:received, sent=:sent, fee=:fee, height=:height, verified=:verified WHERE txid=:txid")?;
+
+        statement.execute(named_params! {
+            ":txid": txid,
+            ":timestamp": timestamp,
+            ":received": transaction.received,
+            ":sent": transaction.sent,
+            ":fee": transaction.fee,
+            ":height": height,
+            ":verified": transaction.verified,
+        })?;
+
+        Ok(())
+    }
+
+    fn insert_last_derivation_index(&self, keychain: String, value: u32) -> Result<i64, Error> {
+        let mut statement = self.connection.prepare_cached(
+            "INSERT INTO last_derivation_indices (keychain, value) VALUES (:keychain, :value)",
+        )?;
+
+        statement.execute(named_params! {
+            ":keychain": keychain,
+            ":value": value,
+        })?;
+
+        Ok(self.connection.last_insert_rowid())
+    }
+
+    fn insert_checksum(&self, keychain: String, checksum: &[u8]) -> Result<i64, Error> {
+        let mut statement = self.connection.prepare_cached(
+            "INSERT INTO checksums (keychain, checksum) VALUES (:keychain, :checksum)",
+        )?;
+        statement.execute(named_params! {
+            ":keychain": keychain,
+            ":checksum": checksum,
+        })?;
+
+        Ok(self.connection.last_insert_rowid())
+    }
+
+    fn update_last_derivation_index(&self, keychain: String, value: u32) -> Result<(), Error> {
+        let mut statement = self.connection.prepare_cached(
+            "INSERT INTO last_derivation_indices (keychain, value) VALUES (:keychain, :value) ON CONFLICT(keychain) DO UPDATE SET value=:value WHERE keychain=:keychain",
+        )?;
+
+        statement.execute(named_params! {
+            ":keychain": keychain,
+            ":value": value,
+        })?;
+
+        Ok(())
+    }
+
+    fn select_script_pubkeys(&self) -> Result<Vec<Script>, Error> {
+        let mut statement = self
+            .connection
+            .prepare_cached("SELECT script FROM script_pubkeys")?;
+        let mut scripts: Vec<Script> = vec![];
+        let mut rows = statement.query([])?;
+        while let Some(row) = rows.next()? {
+            let raw_script: Vec<u8> = row.get(0)?;
+            scripts.push(raw_script.into());
+        }
+
+        Ok(scripts)
+    }
+
+    fn select_script_pubkeys_by_keychain(&self, keychain: String) -> Result<Vec<Script>, Error> {
+        let mut statement = self
+            .connection
+            .prepare_cached("SELECT script FROM script_pubkeys WHERE keychain=:keychain")?;
+        let mut scripts: Vec<Script> = vec![];
+        let mut rows = statement.query(named_params! {":keychain": keychain})?;
+        while let Some(row) = rows.next()? {
+            let raw_script: Vec<u8> = row.get(0)?;
+            scripts.push(raw_script.into());
+        }
+
+        Ok(scripts)
+    }
+
+    fn select_script_pubkey_by_path(
+        &self,
+        keychain: String,
+        child: u32,
+    ) -> Result<Option<Script>, Error> {
+        let mut statement = self.connection.prepare_cached(
+            "SELECT script FROM script_pubkeys WHERE keychain=:keychain AND child=:child",
+        )?;
+        let mut rows = statement.query(named_params! {":keychain": keychain,":child": child})?;
+
+        match rows.next()? {
+            Some(row) => {
+                let script: Vec<u8> = row.get(0)?;
+                let script: Script = script.into();
+                Ok(Some(script))
+            }
+            None => Ok(None),
+        }
+    }
+
+    fn select_script_pubkey_by_script(
+        &self,
+        script: &[u8],
+    ) -> Result<Option<(KeychainKind, u32)>, Error> {
+        let mut statement = self
+            .connection
+            .prepare_cached("SELECT keychain, child FROM script_pubkeys WHERE script=:script")?;
+        let mut rows = statement.query(named_params! {":script": script})?;
+        match rows.next()? {
+            Some(row) => {
+                let keychain: String = row.get(0)?;
+                let keychain: KeychainKind = serde_json::from_str(&keychain)?;
+                let child: u32 = row.get(1)?;
+                Ok(Some((keychain, child)))
+            }
+            None => Ok(None),
+        }
+    }
+
+    fn select_utxos(&self) -> Result<Vec<LocalUtxo>, Error> {
+        let mut statement = self
+            .connection
+            .prepare_cached("SELECT value, keychain, vout, txid, script FROM utxos")?;
+        let mut utxos: Vec<LocalUtxo> = vec![];
+        let mut rows = statement.query([])?;
+        while let Some(row) = rows.next()? {
+            let value = row.get(0)?;
+            let keychain: String = row.get(1)?;
+            let vout = row.get(2)?;
+            let txid: Vec<u8> = row.get(3)?;
+            let script: Vec<u8> = row.get(4)?;
+
+            let keychain: KeychainKind = serde_json::from_str(&keychain)?;
+
+            utxos.push(LocalUtxo {
+                outpoint: OutPoint::new(deserialize(&txid)?, vout),
+                txout: TxOut {
+                    value,
+                    script_pubkey: script.into(),
+                },
+                keychain,
+            })
+        }
+
+        Ok(utxos)
+    }
+
+    fn select_utxo_by_outpoint(
+        &self,
+        txid: &[u8],
+        vout: u32,
+    ) -> Result<Option<(u64, KeychainKind, Script)>, Error> {
+        let mut statement = self.connection.prepare_cached(
+            "SELECT value, keychain, script FROM utxos WHERE txid=:txid AND vout=:vout",
+        )?;
+        let mut rows = statement.query(named_params! {":txid": txid,":vout": vout})?;
+        match rows.next()? {
+            Some(row) => {
+                let value: u64 = row.get(0)?;
+                let keychain: String = row.get(1)?;
+                let keychain: KeychainKind = serde_json::from_str(&keychain)?;
+                let script: Vec<u8> = row.get(2)?;
+                let script: Script = script.into();
+
+                Ok(Some((value, keychain, script)))
+            }
+            None => Ok(None),
+        }
+    }
+
+    fn select_transactions(&self) -> Result<Vec<Transaction>, Error> {
+        let mut statement = self
+            .connection
+            .prepare_cached("SELECT raw_tx FROM transactions")?;
+        let mut txs: Vec<Transaction> = vec![];
+        let mut rows = statement.query([])?;
+        while let Some(row) = rows.next()? {
+            let raw_tx: Vec<u8> = row.get(0)?;
+            let tx: Transaction = deserialize(&raw_tx)?;
+            txs.push(tx);
+        }
+        Ok(txs)
+    }
+
+    fn select_transaction_by_txid(&self, txid: &[u8]) -> Result<Option<Transaction>, Error> {
+        let mut statement = self
+            .connection
+            .prepare_cached("SELECT raw_tx FROM transactions WHERE txid=:txid")?;
+        let mut rows = statement.query(named_params! {":txid": txid})?;
+        match rows.next()? {
+            Some(row) => {
+                let raw_tx: Vec<u8> = row.get(0)?;
+                let tx: Transaction = deserialize(&raw_tx)?;
+                Ok(Some(tx))
+            }
+            None => Ok(None),
+        }
+    }
+
+    fn select_transaction_details_with_raw(&self) -> Result<Vec<TransactionDetails>, Error> {
+        let mut statement = self.connection.prepare_cached("SELECT transaction_details.txid, transaction_details.timestamp, transaction_details.received, transaction_details.sent, transaction_details.fee, transaction_details.height, transaction_details.verified, transactions.raw_tx FROM transaction_details, transactions WHERE transaction_details.txid = transactions.txid")?;
+        let mut transaction_details: Vec<TransactionDetails> = vec![];
+        let mut rows = statement.query([])?;
+        while let Some(row) = rows.next()? {
+            let txid: Vec<u8> = row.get(0)?;
+            let txid: Txid = deserialize(&txid)?;
+            let timestamp: Option<u64> = row.get(1)?;
+            let received: u64 = row.get(2)?;
+            let sent: u64 = row.get(3)?;
+            let fee: Option<u64> = row.get(4)?;
+            let height: Option<u32> = row.get(5)?;
+            let verified: bool = row.get(6)?;
+            let raw_tx: Option<Vec<u8>> = row.get(7)?;
+            let tx: Option<Transaction> = match raw_tx {
+                Some(raw_tx) => {
+                    let tx: Transaction = deserialize(&raw_tx)?;
+                    Some(tx)
+                }
+                None => None,
+            };
+
+            let confirmation_time = match (height, timestamp) {
+                (Some(height), Some(timestamp)) => Some(ConfirmationTime { height, timestamp }),
+                _ => None,
+            };
+
+            transaction_details.push(TransactionDetails {
+                transaction: tx,
+                txid,
+                received,
+                sent,
+                fee,
+                confirmation_time,
+                verified,
+            });
+        }
+        Ok(transaction_details)
+    }
+
+    fn select_transaction_details(&self) -> Result<Vec<TransactionDetails>, Error> {
+        let mut statement = self.connection.prepare_cached(
+            "SELECT txid, timestamp, received, sent, fee, height, verified FROM transaction_details",
+        )?;
+        let mut transaction_details: Vec<TransactionDetails> = vec![];
+        let mut rows = statement.query([])?;
+        while let Some(row) = rows.next()? {
+            let txid: Vec<u8> = row.get(0)?;
+            let txid: Txid = deserialize(&txid)?;
+            let timestamp: Option<u64> = row.get(1)?;
+            let received: u64 = row.get(2)?;
+            let sent: u64 = row.get(3)?;
+            let fee: Option<u64> = row.get(4)?;
+            let height: Option<u32> = row.get(5)?;
+            let verified: bool = row.get(6)?;
+
+            let confirmation_time = match (height, timestamp) {
+                (Some(height), Some(timestamp)) => Some(ConfirmationTime { height, timestamp }),
+                _ => None,
+            };
+
+            transaction_details.push(TransactionDetails {
+                transaction: None,
+                txid,
+                received,
+                sent,
+                fee,
+                confirmation_time,
+                verified,
+            });
+        }
+        Ok(transaction_details)
+    }
+
+    fn select_transaction_details_by_txid(
+        &self,
+        txid: &[u8],
+    ) -> Result<Option<TransactionDetails>, Error> {
+        let mut statement = self.connection.prepare_cached("SELECT transaction_details.timestamp, transaction_details.received, transaction_details.sent, transaction_details.fee, transaction_details.height, transaction_details.verified, transactions.raw_tx FROM transaction_details, transactions WHERE transaction_details.txid=transactions.txid AND transaction_details.txid=:txid")?;
+        let mut rows = statement.query(named_params! { ":txid": txid })?;
+
+        match rows.next()? {
+            Some(row) => {
+                let timestamp: Option<u64> = row.get(0)?;
+                let received: u64 = row.get(1)?;
+                let sent: u64 = row.get(2)?;
+                let fee: Option<u64> = row.get(3)?;
+                let height: Option<u32> = row.get(4)?;
+                let verified: bool = row.get(5)?;
+
+                let raw_tx: Option<Vec<u8>> = row.get(6)?;
+                let tx: Option<Transaction> = match raw_tx {
+                    Some(raw_tx) => {
+                        let tx: Transaction = deserialize(&raw_tx)?;
+                        Some(tx)
+                    }
+                    None => None,
+                };
+
+                let confirmation_time = match (height, timestamp) {
+                    (Some(height), Some(timestamp)) => Some(ConfirmationTime { height, timestamp }),
+                    _ => None,
+                };
+
+                Ok(Some(TransactionDetails {
+                    transaction: tx,
+                    txid: deserialize(txid)?,
+                    received,
+                    sent,
+                    fee,
+                    confirmation_time,
+                    verified,
+                }))
+            }
+            None => Ok(None),
+        }
+    }
+
+    fn select_last_derivation_index_by_keychain(
+        &self,
+        keychain: String,
+    ) -> Result<Option<u32>, Error> {
+        let mut statement = self
+            .connection
+            .prepare_cached("SELECT value FROM last_derivation_indices WHERE keychain=:keychain")?;
+        let mut rows = statement.query(named_params! {":keychain": keychain})?;
+        match rows.next()? {
+            Some(row) => {
+                let value: u32 = row.get(0)?;
+                Ok(Some(value))
+            }
+            None => Ok(None),
+        }
+    }
+
+    fn select_checksum_by_keychain(&self, keychain: String) -> Result<Option<Vec<u8>>, Error> {
+        let mut statement = self
+            .connection
+            .prepare_cached("SELECT checksum FROM checksums WHERE keychain=:keychain")?;
+        let mut rows = statement.query(named_params! {":keychain": keychain})?;
+
+        match rows.next()? {
+            Some(row) => {
+                let checksum: Vec<u8> = row.get(0)?;
+                Ok(Some(checksum))
+            }
+            None => Ok(None),
+        }
+    }
+
+    fn delete_script_pubkey_by_path(&self, keychain: String, child: u32) -> Result<(), Error> {
+        let mut statement = self.connection.prepare_cached(
+            "DELETE FROM script_pubkeys WHERE keychain=:keychain AND child=:child",
+        )?;
+        statement.execute(named_params! {
+            ":keychain": keychain,
+            ":child": child
+        })?;
+
+        Ok(())
+    }
+
+    fn delete_script_pubkey_by_script(&self, script: &[u8]) -> Result<(), Error> {
+        let mut statement = self
+            .connection
+            .prepare_cached("DELETE FROM script_pubkeys WHERE script=:script")?;
+        statement.execute(named_params! {
+            ":script": script
+        })?;
+
+        Ok(())
+    }
+
+    fn delete_utxo_by_outpoint(&self, txid: &[u8], vout: u32) -> Result<(), Error> {
+        let mut statement = self
+            .connection
+            .prepare_cached("DELETE FROM utxos WHERE txid=:txid AND vout=:vout")?;
+        statement.execute(named_params! {
+            ":txid": txid,
+            ":vout": vout
+        })?;
+
+        Ok(())
+    }
+
+    fn delete_transaction_by_txid(&self, txid: &[u8]) -> Result<(), Error> {
+        let mut statement = self
+            .connection
+            .prepare_cached("DELETE FROM transactions WHERE txid=:txid")?;
+        statement.execute(named_params! {":txid": txid})?;
+        Ok(())
+    }
+
+    fn delete_transaction_details_by_txid(&self, txid: &[u8]) -> Result<(), Error> {
+        let mut statement = self
+            .connection
+            .prepare_cached("DELETE FROM transaction_details WHERE txid=:txid")?;
+        statement.execute(named_params! {":txid": txid})?;
+        Ok(())
+    }
+
+    fn delete_last_derivation_index_by_keychain(&self, keychain: String) -> Result<(), Error> {
+        let mut statement = self
+            .connection
+            .prepare_cached("DELETE FROM last_derivation_indices WHERE keychain=:keychain")?;
+        statement.execute(named_params! {
+            ":keychain": &keychain
+        })?;
+
+        Ok(())
+    }
+}
+
+impl BatchOperations for SqliteDatabase {
+    fn set_script_pubkey(
+        &mut self,
+        script: &Script,
+        keychain: KeychainKind,
+        child: u32,
+    ) -> Result<(), Error> {
+        let keychain = serde_json::to_string(&keychain)?;
+        self.insert_script_pubkey(keychain, child, script.as_bytes())?;
+        Ok(())
+    }
+
+    fn set_utxo(&mut self, utxo: &LocalUtxo) -> Result<(), Error> {
+        self.insert_utxo(
+            utxo.txout.value,
+            serde_json::to_string(&utxo.keychain)?,
+            utxo.outpoint.vout,
+            &utxo.outpoint.txid,
+            utxo.txout.script_pubkey.as_bytes(),
+        )?;
+        Ok(())
+    }
+
+    fn set_raw_tx(&mut self, transaction: &Transaction) -> Result<(), Error> {
+        match self.select_transaction_by_txid(&transaction.txid())? {
+            Some(_) => {
+                self.update_transaction(&transaction.txid(), &serialize(transaction))?;
+            }
+            None => {
+                self.insert_transaction(&transaction.txid(), &serialize(transaction))?;
+            }
+        }
+        Ok(())
+    }
+
+    fn set_tx(&mut self, transaction: &TransactionDetails) -> Result<(), Error> {
+        match self.select_transaction_details_by_txid(&transaction.txid)? {
+            Some(_) => {
+                self.update_transaction_details(transaction)?;
+            }
+            None => {
+                self.insert_transaction_details(transaction)?;
+            }
+        }
+
+        if let Some(tx) = &transaction.transaction {
+            self.set_raw_tx(tx)?;
+        }
+
+        Ok(())
+    }
+
+    fn set_last_index(&mut self, keychain: KeychainKind, value: u32) -> Result<(), Error> {
+        self.update_last_derivation_index(serde_json::to_string(&keychain)?, value)?;
+        Ok(())
+    }
+
+    fn del_script_pubkey_from_path(
+        &mut self,
+        keychain: KeychainKind,
+        child: u32,
+    ) -> Result<Option<Script>, Error> {
+        let keychain = serde_json::to_string(&keychain)?;
+        let script = self.select_script_pubkey_by_path(keychain.clone(), child)?;
+        match script {
+            Some(script) => {
+                self.delete_script_pubkey_by_path(keychain, child)?;
+                Ok(Some(script))
+            }
+            None => Ok(None),
+        }
+    }
+
+    fn del_path_from_script_pubkey(
+        &mut self,
+        script: &Script,
+    ) -> Result<Option<(KeychainKind, u32)>, Error> {
+        match self.select_script_pubkey_by_script(script.as_bytes())? {
+            Some((keychain, child)) => {
+                self.delete_script_pubkey_by_script(script.as_bytes())?;
+                Ok(Some((keychain, child)))
+            }
+            None => Ok(None),
+        }
+    }
+
+    fn del_utxo(&mut self, outpoint: &OutPoint) -> Result<Option<LocalUtxo>, Error> {
+        match self.select_utxo_by_outpoint(&outpoint.txid, outpoint.vout)? {
+            Some((value, keychain, script_pubkey)) => {
+                self.delete_utxo_by_outpoint(&outpoint.txid, outpoint.vout)?;
+                Ok(Some(LocalUtxo {
+                    outpoint: *outpoint,
+                    txout: TxOut {
+                        value,
+                        script_pubkey,
+                    },
+                    keychain,
+                }))
+            }
+            None => Ok(None),
+        }
+    }
+
+    fn del_raw_tx(&mut self, txid: &Txid) -> Result<Option<Transaction>, Error> {
+        match self.select_transaction_by_txid(txid)? {
+            Some(tx) => {
+                self.delete_transaction_by_txid(txid)?;
+                Ok(Some(tx))
+            }
+            None => Ok(None),
+        }
+    }
+
+    fn del_tx(
+        &mut self,
+        txid: &Txid,
+        include_raw: bool,
+    ) -> Result<Option<TransactionDetails>, Error> {
+        match self.select_transaction_details_by_txid(txid)? {
+            Some(transaction_details) => {
+                self.delete_transaction_details_by_txid(txid)?;
+
+                if include_raw {
+                    self.delete_transaction_by_txid(txid)?;
+                }
+                Ok(Some(transaction_details))
+            }
+            None => Ok(None),
+        }
+    }
+
+    fn del_last_index(&mut self, keychain: KeychainKind) -> Result<Option<u32>, Error> {
+        let keychain = serde_json::to_string(&keychain)?;
+        match self.select_last_derivation_index_by_keychain(keychain.clone())? {
+            Some(value) => {
+                self.delete_last_derivation_index_by_keychain(keychain)?;
+
+                Ok(Some(value))
+            }
+            None => Ok(None),
+        }
+    }
+}
+
+impl Database for SqliteDatabase {
+    fn check_descriptor_checksum<B: AsRef<[u8]>>(
+        &mut self,
+        keychain: KeychainKind,
+        bytes: B,
+    ) -> Result<(), Error> {
+        let keychain = serde_json::to_string(&keychain)?;
+
+        match self.select_checksum_by_keychain(keychain.clone())? {
+            Some(checksum) => {
+                if checksum == bytes.as_ref().to_vec() {
+                    Ok(())
+                } else {
+                    Err(Error::ChecksumMismatch)
+                }
+            }
+            None => {
+                self.insert_checksum(keychain, bytes.as_ref())?;
+                Ok(())
+            }
+        }
+    }
+
+    fn iter_script_pubkeys(&self, keychain: Option<KeychainKind>) -> Result<Vec<Script>, Error> {
+        match keychain {
+            Some(keychain) => {
+                let keychain = serde_json::to_string(&keychain)?;
+                self.select_script_pubkeys_by_keychain(keychain)
+            }
+            None => self.select_script_pubkeys(),
+        }
+    }
+
+    fn iter_utxos(&self) -> Result<Vec<LocalUtxo>, Error> {
+        self.select_utxos()
+    }
+
+    fn iter_raw_txs(&self) -> Result<Vec<Transaction>, Error> {
+        self.select_transactions()
+    }
+
+    fn iter_txs(&self, include_raw: bool) -> Result<Vec<TransactionDetails>, Error> {
+        match include_raw {
+            true => self.select_transaction_details_with_raw(),
+            false => self.select_transaction_details(),
+        }
+    }
+
+    fn get_script_pubkey_from_path(
+        &self,
+        keychain: KeychainKind,
+        child: u32,
+    ) -> Result<Option<Script>, Error> {
+        let keychain = serde_json::to_string(&keychain)?;
+        match self.select_script_pubkey_by_path(keychain, child)? {
+            Some(script) => Ok(Some(script)),
+            None => Ok(None),
+        }
+    }
+
+    fn get_path_from_script_pubkey(
+        &self,
+        script: &Script,
+    ) -> Result<Option<(KeychainKind, u32)>, Error> {
+        match self.select_script_pubkey_by_script(script.as_bytes())? {
+            Some((keychain, child)) => Ok(Some((keychain, child))),
+            None => Ok(None),
+        }
+    }
+
+    fn get_utxo(&self, outpoint: &OutPoint) -> Result<Option<LocalUtxo>, Error> {
+        match self.select_utxo_by_outpoint(&outpoint.txid, outpoint.vout)? {
+            Some((value, keychain, script_pubkey)) => Ok(Some(LocalUtxo {
+                outpoint: *outpoint,
+                txout: TxOut {
+                    value,
+                    script_pubkey,
+                },
+                keychain,
+            })),
+            None => Ok(None),
+        }
+    }
+
+    fn get_raw_tx(&self, txid: &Txid) -> Result<Option<Transaction>, Error> {
+        match self.select_transaction_by_txid(txid)? {
+            Some(tx) => Ok(Some(tx)),
+            None => Ok(None),
+        }
+    }
+
+    fn get_tx(&self, txid: &Txid, include_raw: bool) -> Result<Option<TransactionDetails>, Error> {
+        match self.select_transaction_details_by_txid(txid)? {
+            Some(mut transaction_details) => {
+                if !include_raw {
+                    transaction_details.transaction = None;
+                }
+                Ok(Some(transaction_details))
+            }
+            None => Ok(None),
+        }
+    }
+
+    fn get_last_index(&self, keychain: KeychainKind) -> Result<Option<u32>, Error> {
+        let keychain = serde_json::to_string(&keychain)?;
+        let value = self.select_last_derivation_index_by_keychain(keychain)?;
+        Ok(value)
+    }
+
+    fn increment_last_index(&mut self, keychain: KeychainKind) -> Result<u32, Error> {
+        let keychain_string = serde_json::to_string(&keychain)?;
+        match self.get_last_index(keychain)? {
+            Some(value) => {
+                self.update_last_derivation_index(keychain_string, value + 1)?;
+                Ok(value + 1)
+            }
+            None => {
+                self.insert_last_derivation_index(keychain_string, 0)?;
+                Ok(0)
+            }
+        }
+    }
+
+    fn flush(&mut self) -> Result<(), Error> {
+        Ok(())
+    }
+}
+
+impl BatchDatabase for SqliteDatabase {
+    type Batch = SqliteDatabase;
+
+    fn begin_batch(&self) -> Self::Batch {
+        let db = SqliteDatabase::new(self.path.clone());
+        db.connection.execute("BEGIN TRANSACTION", []).unwrap();
+        db
+    }
+
+    fn commit_batch(&mut self, batch: Self::Batch) -> Result<(), Error> {
+        batch.connection.execute("COMMIT TRANSACTION", [])?;
+        Ok(())
+    }
+}
+
+pub fn get_connection(path: &str) -> Result<Connection, Error> {
+    let connection = Connection::open(path)?;
+    migrate(&connection)?;
+    Ok(connection)
+}
+
+pub fn get_schema_version(conn: &Connection) -> rusqlite::Result<i32> {
+    let statement = conn.prepare_cached("SELECT version FROM version");
+    match statement {
+        Err(rusqlite::Error::SqliteFailure(e, Some(msg))) => {
+            if msg == "no such table: version" {
+                Ok(0)
+            } else {
+                Err(rusqlite::Error::SqliteFailure(e, Some(msg)))
+            }
+        }
+        Ok(mut stmt) => {
+            let mut rows = stmt.query([])?;
+            match rows.next()? {
+                Some(row) => {
+                    let version: i32 = row.get(0)?;
+                    Ok(version)
+                }
+                None => Ok(0),
+            }
+        }
+        _ => Ok(0),
+    }
+}
+
+pub fn set_schema_version(conn: &Connection, version: i32) -> rusqlite::Result<usize> {
+    conn.execute(
+        "UPDATE version SET version=:version",
+        named_params! {":version": version},
+    )
+}
+
+pub fn migrate(conn: &Connection) -> rusqlite::Result<()> {
+    let version = get_schema_version(conn)?;
+    let stmts = &MIGRATIONS[(version as usize)..];
+    let mut i: i32 = version;
+
+    if version == MIGRATIONS.len() as i32 {
+        log::info!("db up to date, no migration needed");
+        return Ok(());
+    }
+
+    for stmt in stmts {
+        let res = conn.execute(stmt, []);
+        if res.is_err() {
+            println!("migration failed on:\n{}\n{:?}", stmt, res);
+            break;
+        }
+
+        i += 1;
+    }
+
+    set_schema_version(conn, i)?;
+
+    Ok(())
+}
+
+#[cfg(test)]
+pub mod test {
+    use crate::database::SqliteDatabase;
+    use std::time::{SystemTime, UNIX_EPOCH};
+
+    fn get_database() -> SqliteDatabase {
+        let time = SystemTime::now().duration_since(UNIX_EPOCH).unwrap();
+        let mut dir = std::env::temp_dir();
+        dir.push(format!("bdk_{}", time.as_nanos()));
+        SqliteDatabase::new(String::from(dir.to_str().unwrap()))
+    }
+
+    #[test]
+    fn test_script_pubkey() {
+        crate::database::test::test_script_pubkey(get_database());
+    }
+
+    #[test]
+    fn test_batch_script_pubkey() {
+        crate::database::test::test_batch_script_pubkey(get_database());
+    }
+
+    #[test]
+    fn test_iter_script_pubkey() {
+        crate::database::test::test_iter_script_pubkey(get_database());
+    }
+
+    #[test]
+    fn test_del_script_pubkey() {
+        crate::database::test::test_del_script_pubkey(get_database());
+    }
+
+    #[test]
+    fn test_utxo() {
+        crate::database::test::test_utxo(get_database());
+    }
+
+    #[test]
+    fn test_raw_tx() {
+        crate::database::test::test_raw_tx(get_database());
+    }
+
+    #[test]
+    fn test_tx() {
+        crate::database::test::test_tx(get_database());
+    }
+
+    #[test]
+    fn test_last_index() {
+        crate::database::test::test_last_index(get_database());
+    }
+}

src/descriptor/dsl.rs

@@ -175,7 +175,7 @@ macro_rules! impl_node_opcode_two {
 #[doc(hidden)]
 #[macro_export]
 macro_rules! impl_node_opcode_three {
-    ( $terminal_variant:ident, $( $inner:tt )* ) => {
+    ( $terminal_variant:ident, $( $inner:tt )* ) => ({
         use $crate::descriptor::CheckMiniscript;
 
         let inner = $crate::fragment_internal!( @t $( $inner )* );
@@ -201,7 +201,7 @@ macro_rules! impl_node_opcode_three {
 
                 Ok((minisc, a_keymap, networks))
             })
-    };
+    });
 }
 
 #[doc(hidden)]
@@ -571,8 +571,9 @@ macro_rules! fragment {
     ( pk ( $key:expr ) ) => ({
         $crate::fragment!(c:pk_k ( $key ))
     });
-    ( pk_h ( $key_hash:expr ) ) => ({
-        $crate::impl_leaf_opcode_value!(PkH, $key_hash)
+    ( pk_h ( $key:expr ) ) => ({
+        let secp = $crate::bitcoin::secp256k1::Secp256k1::new();
+        $crate::keys::make_pkh($key, &secp)
     });
     ( after ( $value:expr ) ) => ({
         $crate::impl_leaf_opcode_value!(After, $value)
@@ -601,6 +602,9 @@ macro_rules! fragment {
     ( and_or ( $( $inner:tt )* ) ) => ({
         $crate::impl_node_opcode_three!(AndOr, $( $inner )*)
     });
+    ( andor ( $( $inner:tt )* ) ) => ({
+        $crate::impl_node_opcode_three!(AndOr, $( $inner )*)
+    });
     ( or_b ( $( $inner:tt )* ) ) => ({
         $crate::impl_node_opcode_two!(OrB, $( $inner )*)
     });
@@ -790,6 +794,25 @@ mod test {
         );
     }
 
+    #[test]
+    fn test_fixed_threeop_descriptors() {
+        let redeem_key = bitcoin::PublicKey::from_str(
+            "03a34b99f22c790c4e36b2b3c2c35a36db06226e41c692fc82b8b56ac1c540c5bd",
+        )
+        .unwrap();
+        let move_key = bitcoin::PublicKey::from_str(
+            "032e58afe51f9ed8ad3cc7897f634d881fdbe49a81564629ded8156bebd2ffd1af",
+        )
+        .unwrap();
+
+        check(
+            descriptor!(sh(wsh(and_or(pk(redeem_key), older(1000), pk(move_key))))),
+            true,
+            true,
+            &["2MypGwr5eQWAWWJtiJgUEToVxc4zuokjQRe"],
+        );
+    }
+
     #[test]
     fn test_bip32_legacy_descriptors() {
         let xprv = bip32::ExtendedPrivKey::from_str("tprv8ZgxMBicQKsPcx5nBGsR63Pe8KnRUqmbJNENAfGftF3yuXoMMoVJJcYeUw5eVkm9WBPjWYt6HMWYJNesB5HaNVBaFc1M6dRjWSYnmewUMYy").unwrap();

src/descriptor/policy.rs

@@ -47,14 +47,12 @@ use bitcoin::util::bip32::Fingerprint;
 use bitcoin::PublicKey;
 
 use miniscript::descriptor::{DescriptorPublicKey, ShInner, SortedMultiVec, WshInner};
-use miniscript::{
-    Descriptor, Miniscript, MiniscriptKey, Satisfier, ScriptContext, Terminal, ToPublicKey,
-};
+use miniscript::{Descriptor, Miniscript, MiniscriptKey, Satisfier, ScriptContext, Terminal};
 
 #[allow(unused_imports)]
 use log::{debug, error, info, trace};
 
-use crate::descriptor::{DerivedDescriptorKey, ExtractPolicy};
+use crate::descriptor::ExtractPolicy;
 use crate::wallet::signer::{SignerId, SignersContainer};
 use crate::wallet::utils::{self, After, Older, SecpCtx};
 
@@ -88,13 +86,6 @@ impl PkOrF {
             },
         }
     }
-
-    fn from_key_hash(k: hash160::Hash) -> Self {
-        PkOrF {
-            pubkey_hash: Some(k),
-            ..Default::default()
-        }
-    }
 }
 
 /// An item that needs to be satisfied
@@ -779,25 +770,6 @@ fn signature_in_psbt(psbt: &Psbt, key: &DescriptorPublicKey, secp: &SecpCtx) ->
     })
 }
 
-fn signature_key(
-    key: &<DescriptorPublicKey as MiniscriptKey>::Hash,
-    signers: &SignersContainer,
-    secp: &SecpCtx,
-) -> Policy {
-    let key_hash = DerivedDescriptorKey::new(key.clone(), secp)
-        .to_public_key()
-        .to_pubkeyhash();
-    let mut policy: Policy = SatisfiableItem::Signature(PkOrF::from_key_hash(key_hash)).into();
-
-    if signers.find(SignerId::PkHash(key_hash)).is_some() {
-        policy.contribution = Satisfaction::Complete {
-            condition: Default::default(),
-        }
-    }
-
-    policy
-}
-
 impl<Ctx: ScriptContext> ExtractPolicy for Miniscript<DescriptorPublicKey, Ctx> {
     fn extract_policy(
         &self,
@@ -809,7 +781,7 @@ impl<Ctx: ScriptContext> ExtractPolicy for Miniscript<DescriptorPublicKey, Ctx>
             // Leaves
             Terminal::True | Terminal::False => None,
             Terminal::PkK(pubkey) => Some(signature(pubkey, signers, build_sat, secp)),
-            Terminal::PkH(pubkey_hash) => Some(signature_key(pubkey_hash, signers, secp)),
+            Terminal::PkH(pubkey_hash) => Some(signature(pubkey_hash, signers, build_sat, secp)),
             Terminal::After(value) => {
                 let mut policy: Policy = SatisfiableItem::AbsoluteTimelock { value: *value }.into();
                 policy.contribution = Satisfaction::Complete {
@@ -1444,6 +1416,7 @@ mod test {
 
     const ALICE_TPRV_STR:&str = "tprv8ZgxMBicQKsPf6T5X327efHnvJDr45Xnb8W4JifNWtEoqXu9MRYS4v1oYe6DFcMVETxy5w3bqpubYRqvcVTqovG1LifFcVUuJcbwJwrhYzP";
     const BOB_TPRV_STR:&str = "tprv8ZgxMBicQKsPeinZ155cJAn117KYhbaN6MV3WeG6sWhxWzcvX1eg1awd4C9GpUN1ncLEM2rzEvunAg3GizdZD4QPPCkisTz99tXXB4wZArp";
+    const CAROL_TPRV_STR:&str = "tprv8ZgxMBicQKsPdC3CicFifuLCEyVVdXVUNYorxUWj3iGZ6nimnLAYAY9SYB7ib8rKzRxrCKFcEytCt6szwd2GHnGPRCBLAEAoSVDefSNk4Bt";
     const ALICE_BOB_PATH: &str = "m/0'";
 
     #[test]
@@ -1602,4 +1575,28 @@ mod test {
         );
         //println!("{}", serde_json::to_string(&policy_expired_signed).unwrap());
     }
+
+    #[test]
+    fn test_extract_pkh() {
+        let secp = Secp256k1::new();
+
+        let (prvkey_alice, _, _) = setup_keys(ALICE_TPRV_STR, ALICE_BOB_PATH, &secp);
+        let (prvkey_bob, _, _) = setup_keys(BOB_TPRV_STR, ALICE_BOB_PATH, &secp);
+        let (prvkey_carol, _, _) = setup_keys(CAROL_TPRV_STR, ALICE_BOB_PATH, &secp);
+
+        let desc = descriptor!(wsh(c: andor(
+            pk(prvkey_alice),
+            pk_k(prvkey_bob),
+            pk_h(prvkey_carol),
+        )))
+        .unwrap();
+
+        let (wallet_desc, keymap) = desc
+            .into_wallet_descriptor(&secp, Network::Testnet)
+            .unwrap();
+        let signers_container = Arc::new(SignersContainer::from(keymap));
+
+        let policy = wallet_desc.extract_policy(&signers_container, BuildSatisfaction::None, &secp);
+        assert!(policy.is_ok());
+    }
 }

src/error.rs

@@ -24,10 +24,6 @@ pub enum Error {
     Generic(String),
     /// This error is thrown when trying to convert Bare and Public key script to address
     ScriptDoesntHaveAddressForm,
-    /// Found multiple outputs when `single_recipient` option has been specified
-    SingleRecipientMultipleOutputs,
-    /// `single_recipient` option is selected but neither `drain_wallet` nor `manually_selected_only` are
-    SingleRecipientNoInputs,
     /// Cannot build a tx without recipients
     NoRecipients,
     /// `manually_selected_only` option is selected but no utxo has been passed
@@ -90,6 +86,10 @@ pub enum Error {
         /// found network, for example the network of the bitcoin node
         found: Network,
     },
+    #[cfg(feature = "verify")]
+    /// Transaction verification error
+    Verification(crate::wallet::verify::VerifyError),
+
     /// Progress value must be between `0.0` (included) and `100.0` (included)
     InvalidProgressValue(f32),
     /// Progress update error (maybe the channel has been closed)
@@ -130,7 +130,7 @@ pub enum Error {
     Electrum(electrum_client::Error),
     #[cfg(feature = "esplora")]
     /// Esplora client error
-    Esplora(crate::blockchain::esplora::EsploraError),
+    Esplora(Box<crate::blockchain::esplora::EsploraError>),
     #[cfg(feature = "compact_filters")]
     /// Compact filters client error)
     CompactFilters(crate::blockchain::compact_filters::CompactFiltersError),
@@ -140,6 +140,9 @@ pub enum Error {
     #[cfg(feature = "rpc")]
     /// Rpc client error
     Rpc(bitcoincore_rpc::Error),
+    #[cfg(feature = "sqlite")]
+    /// Rusqlite client error
+    Rusqlite(rusqlite::Error),
 }
 
 impl fmt::Display for Error {
@@ -190,12 +193,12 @@ impl_error!(bitcoin::util::psbt::PsbtParseError, PsbtParse);
 
 #[cfg(feature = "electrum")]
 impl_error!(electrum_client::Error, Electrum);
-#[cfg(feature = "esplora")]
-impl_error!(crate::blockchain::esplora::EsploraError, Esplora);
 #[cfg(feature = "key-value-db")]
 impl_error!(sled::Error, Sled);
 #[cfg(feature = "rpc")]
 impl_error!(bitcoincore_rpc::Error, Rpc);
+#[cfg(feature = "sqlite")]
+impl_error!(rusqlite::Error, Rusqlite);
 
 #[cfg(feature = "compact_filters")]
 impl From<crate::blockchain::compact_filters::CompactFiltersError> for Error {
@@ -206,3 +209,20 @@ impl From<crate::blockchain::compact_filters::CompactFiltersError> for Error {
         }
     }
 }
+
+#[cfg(feature = "verify")]
+impl From<crate::wallet::verify::VerifyError> for Error {
+    fn from(other: crate::wallet::verify::VerifyError) -> Self {
+        match other {
+            crate::wallet::verify::VerifyError::Global(inner) => *inner,
+            err => Error::Verification(err),
+        }
+    }
+}
+
+#[cfg(feature = "esplora")]
+impl From<crate::blockchain::esplora::EsploraError> for Error {
+    fn from(other: crate::blockchain::esplora::EsploraError) -> Self {
+        Error::Esplora(Box::new(other))
+    }
+}

src/keys/bip39.rs

@@ -40,7 +40,7 @@ pub type MnemonicWithPassphrase = (Mnemonic, Option<String>);
 #[cfg_attr(docsrs, doc(cfg(feature = "keys-bip39")))]
 impl<Ctx: ScriptContext> DerivableKey<Ctx> for Seed {
     fn into_extended_key(self) -> Result<ExtendedKey<Ctx>, KeyError> {
-        Ok(bip32::ExtendedPrivKey::new_master(Network::Bitcoin, &self.as_bytes())?.into())
+        Ok(bip32::ExtendedPrivKey::new_master(Network::Bitcoin, self.as_bytes())?.into())
     }
 
     fn into_descriptor_key(

src/keys/mod.rs

@@ -753,6 +753,20 @@ pub fn make_pk<Pk: IntoDescriptorKey<Ctx>, Ctx: ScriptContext>(
     Ok((minisc, key_map, valid_networks))
 }
 
+// Used internally by `bdk::fragment!` to build `pk_h()` fragments
+#[doc(hidden)]
+pub fn make_pkh<Pk: IntoDescriptorKey<Ctx>, Ctx: ScriptContext>(
+    descriptor_key: Pk,
+    secp: &SecpCtx,
+) -> Result<(Miniscript<DescriptorPublicKey, Ctx>, KeyMap, ValidNetworks), DescriptorError> {
+    let (key, key_map, valid_networks) = descriptor_key.into_descriptor_key()?.extract(secp)?;
+    let minisc = Miniscript::from_ast(Terminal::PkH(key))?;
+
+    minisc.check_minsicript()?;
+
+    Ok((minisc, key_map, valid_networks))
+}
+
 // Used internally by `bdk::fragment!` to build `multi()` fragments
 #[doc(hidden)]
 pub fn make_multi<Pk: IntoDescriptorKey<Ctx>, Ctx: ScriptContext>(

src/lib.rs

@@ -40,7 +40,7 @@
 //! interact with the bitcoin P2P network.
 //!
 //! ```toml
-//! bdk = "0.8.0"
+//! bdk = "0.13.0"
 //! ```
 #![cfg_attr(
     feature = "electrum",
@@ -205,11 +205,24 @@ extern crate serde;
 #[macro_use]
 extern crate serde_json;
 
+#[cfg(all(feature = "reqwest", feature = "ureq"))]
+compile_error!("Features reqwest and ureq are mutually exclusive and cannot be enabled together");
+
 #[cfg(all(feature = "async-interface", feature = "electrum"))]
 compile_error!(
     "Features async-interface and electrum are mutually exclusive and cannot be enabled together"
 );
 
+#[cfg(all(feature = "async-interface", feature = "ureq"))]
+compile_error!(
+    "Features async-interface and ureq are mutually exclusive and cannot be enabled together"
+);
+
+#[cfg(all(feature = "async-interface", feature = "compact_filters"))]
+compile_error!(
+    "Features async-interface and compact_filters are mutually exclusive and cannot be enabled together"
+);
+
 #[cfg(feature = "keys-bip39")]
 extern crate bip39;
 
@@ -228,19 +241,13 @@ pub extern crate bitcoincore_rpc;
 #[cfg(feature = "electrum")]
 pub extern crate electrum_client;
 
-#[cfg(feature = "esplora")]
-pub extern crate reqwest;
-
 #[cfg(feature = "key-value-db")]
 pub extern crate sled;
 
-#[allow(unused_imports)]
-#[cfg(test)]
-#[allow(unused_imports)]
-#[cfg(test)]
-#[macro_use]
-pub extern crate serial_test;
+#[cfg(feature = "sqlite")]
+pub extern crate rusqlite;
 
+#[allow(unused_imports)]
 #[macro_use]
 pub(crate) mod error;
 pub mod blockchain;

src/psbt/mod.rs

@@ -43,8 +43,8 @@ impl PsbtUtils for Psbt {
 mod test {
     use crate::bitcoin::TxIn;
     use crate::psbt::Psbt;
-    use crate::wallet::test::{get_funded_wallet, get_test_wpkh};
     use crate::wallet::AddressIndex;
+    use crate::wallet::{get_funded_wallet, test::get_test_wpkh};
     use crate::SignOptions;
     use std::str::FromStr;
 

src/testutils/blockchain_tests.rs

@@ -6,38 +6,54 @@ use bitcoin::{Address, Amount, Script, Transaction, Txid};
 pub use bitcoincore_rpc::bitcoincore_rpc_json::AddressType;
 pub use bitcoincore_rpc::{Auth, Client as RpcClient, RpcApi};
 use core::str::FromStr;
+use electrsd::bitcoind::BitcoinD;
+use electrsd::{bitcoind, ElectrsD};
 pub use electrum_client::{Client as ElectrumClient, ElectrumApi};
 #[allow(unused_imports)]
-use log::{debug, error, info, trace};
+use log::{debug, error, info, log_enabled, trace, Level};
 use std::collections::HashMap;
 use std::env;
 use std::ops::Deref;
-use std::path::PathBuf;
 use std::time::Duration;
 
 pub struct TestClient {
-    client: RpcClient,
-    electrum: ElectrumClient,
+    pub bitcoind: BitcoinD,
+    pub electrsd: ElectrsD,
 }
 
 impl TestClient {
-    pub fn new(rpc_host_and_wallet: String, rpc_wallet_name: String) -> Self {
-        let client = RpcClient::new(
-            format!("http://{}/wallet/{}", rpc_host_and_wallet, rpc_wallet_name),
-            get_auth(),
-        )
-        .unwrap();
-        let electrum = ElectrumClient::new(&get_electrum_url()).unwrap();
+    pub fn new(bitcoind_exe: String, electrs_exe: String) -> Self {
+        debug!("launching {} and {}", &bitcoind_exe, &electrs_exe);
 
-        TestClient { client, electrum }
+        let mut conf = bitcoind::Conf::default();
+        conf.view_stdout = log_enabled!(Level::Debug);
+        let bitcoind = BitcoinD::with_conf(bitcoind_exe, &conf).unwrap();
+
+        let mut conf = electrsd::Conf::default();
+        conf.view_stderr = log_enabled!(Level::Debug);
+        conf.http_enabled = cfg!(feature = "test-esplora");
+
+        let electrsd = ElectrsD::with_conf(electrs_exe, &bitcoind, &conf).unwrap();
+
+        let node_address = bitcoind.client.get_new_address(None, None).unwrap();
+        bitcoind
+            .client
+            .generate_to_address(101, &node_address)
+            .unwrap();
+
+        let mut test_client = TestClient { bitcoind, electrsd };
+        TestClient::wait_for_block(&mut test_client, 101);
+        test_client
     }
 
     fn wait_for_tx(&mut self, txid: Txid, monitor_script: &Script) {
         // wait for electrs to index the tx
         exponential_backoff_poll(|| {
+            self.electrsd.trigger().unwrap();
             trace!("wait_for_tx {}", txid);
 
-            self.electrum
+            self.electrsd
+                .client
                 .script_get_history(monitor_script)
                 .unwrap()
                 .iter()
@@ -46,12 +62,13 @@ impl TestClient {
     }
 
     fn wait_for_block(&mut self, min_height: usize) {
-        self.electrum.block_headers_subscribe().unwrap();
+        self.electrsd.client.block_headers_subscribe().unwrap();
 
         loop {
             let header = exponential_backoff_poll(|| {
-                self.electrum.ping().unwrap();
-                self.electrum.block_headers_pop().unwrap()
+                self.electrsd.trigger().unwrap();
+                self.electrsd.client.ping().unwrap();
+                self.electrsd.client.block_headers_pop().unwrap()
             });
             if header.height >= min_height {
                 break;
@@ -96,10 +113,13 @@ impl TestClient {
             .unwrap();
 
         // broadcast through electrum so that it caches the tx immediately
+
         let txid = self
-            .electrum
+            .electrsd
+            .client
             .transaction_broadcast(&deserialize(&tx.hex).unwrap())
             .unwrap();
+        debug!("broadcasted to electrum {}", txid);
 
         if let Some(num) = meta_tx.min_confirmations {
             self.generate(num, None);
@@ -209,7 +229,7 @@ impl TestClient {
         let block_hex: String = serialize(&block).to_hex();
         debug!("generated block hex: {}", block_hex);
 
-        self.electrum.block_headers_subscribe().unwrap();
+        self.electrsd.client.block_headers_subscribe().unwrap();
 
         let submit_result: serde_json::Value =
             self.call("submitblock", &[block_hex.into()]).unwrap();
@@ -237,7 +257,7 @@ impl TestClient {
     }
 
     pub fn invalidate(&mut self, num_blocks: u64) {
-        self.electrum.block_headers_subscribe().unwrap();
+        self.electrsd.client.block_headers_subscribe().unwrap();
 
         let best_hash = self.get_best_block_hash().unwrap();
         let initial_height = self.get_block_info(&best_hash).unwrap().height;
@@ -288,16 +308,25 @@ impl Deref for TestClient {
     type Target = RpcClient;
 
     fn deref(&self) -> &Self::Target {
-        &self.client
+        &self.bitcoind.client
     }
 }
 
 impl Default for TestClient {
     fn default() -> Self {
-        let rpc_host_and_port =
-            env::var("BDK_RPC_URL").unwrap_or_else(|_| "127.0.0.1:18443".to_string());
-        let wallet = env::var("BDK_RPC_WALLET").unwrap_or_else(|_| "bdk-test".to_string());
-        Self::new(rpc_host_and_port, wallet)
+        let bitcoind_exe = env::var("BITCOIND_EXE")
+            .ok()
+            .or(bitcoind::downloaded_exe_path())
+            .expect(
+                "you should provide env var BITCOIND_EXE or specifiy a bitcoind version feature",
+            );
+        let electrs_exe = env::var("ELECTRS_EXE")
+            .ok()
+            .or(electrsd::downloaded_exe_path())
+            .expect(
+                "you should provide env var ELECTRS_EXE or specifiy a electrsd version feature",
+            );
+        Self::new(bitcoind_exe, electrs_exe)
     }
 }
 
@@ -317,27 +346,13 @@ where
     }
 }
 
-// TODO: we currently only support env vars, we could also parse a toml file
-fn get_auth() -> Auth {
-    match env::var("BDK_RPC_AUTH").as_ref().map(String::as_ref) {
-        Ok("USER_PASS") => Auth::UserPass(
-            env::var("BDK_RPC_USER").unwrap(),
-            env::var("BDK_RPC_PASS").unwrap(),
-        ),
-        _ => Auth::CookieFile(PathBuf::from(
-            env::var("BDK_RPC_COOKIEFILE")
-                .unwrap_or_else(|_| "/home/user/.bitcoin/regtest/.cookie".to_string()),
-        )),
-    }
-}
-
 /// This macro runs blockchain tests against a `Blockchain` implementation. It requires access to a
 /// Bitcoin core wallet via RPC. At the moment you have to dig into the code yourself and look at
 /// the setup required to run the tests yourself.
 #[macro_export]
 macro_rules! bdk_blockchain_tests {
     (
-     fn test_instance() -> $blockchain:ty $block:block) => {
+     fn $_fn_name:ident ( $( $test_client:ident : &TestClient )? $(,)? ) -> $blockchain:ty $block:block) => {
         #[cfg(test)]
         mod bdk_blockchain_tests {
             use $crate::bitcoin::Network;
@@ -347,16 +362,17 @@ macro_rules! bdk_blockchain_tests {
             use $crate::types::KeychainKind;
             use $crate::{Wallet, FeeRate};
             use $crate::testutils;
-            use $crate::serial_test::serial;
 
             use super::*;
 
-            fn get_blockchain() -> $blockchain {
+            #[allow(unused_variables)]
+            fn get_blockchain(test_client: &TestClient) -> $blockchain {
+                $( let $test_client = test_client; )?
                 $block
             }
 
-            fn get_wallet_from_descriptors(descriptors: &(String, Option<String>)) -> Wallet<$blockchain, MemoryDatabase> {
-                Wallet::new(&descriptors.0.to_string(), descriptors.1.as_ref(), Network::Regtest, MemoryDatabase::new(), get_blockchain()).unwrap()
+            fn get_wallet_from_descriptors(descriptors: &(String, Option<String>), test_client: &TestClient) -> Wallet<$blockchain, MemoryDatabase> {
+                Wallet::new(&descriptors.0.to_string(), descriptors.1.as_ref(), Network::Regtest, MemoryDatabase::new(), get_blockchain(test_client)).unwrap()
             }
 
             fn init_single_sig() -> (Wallet<$blockchain, MemoryDatabase>, (String, Option<String>), TestClient) {
@@ -367,7 +383,7 @@ macro_rules! bdk_blockchain_tests {
                 };
 
                 let test_client = TestClient::default();
-                let wallet = get_wallet_from_descriptors(&descriptors);
+                let wallet = get_wallet_from_descriptors(&descriptors, &test_client);
 
                 // rpc need to call import_multi before receiving any tx, otherwise will not see tx in the mempool
                 #[cfg(feature = "test-rpc")]
@@ -377,7 +393,6 @@ macro_rules! bdk_blockchain_tests {
             }
 
             #[test]
-            #[serial]
             fn test_sync_simple() {
                 let (wallet, descriptors, mut test_client) = init_single_sig();
 
@@ -400,7 +415,6 @@ macro_rules! bdk_blockchain_tests {
             }
 
             #[test]
-            #[serial]
             fn test_sync_stop_gap_20() {
                 let (wallet, descriptors, mut test_client) = init_single_sig();
 
@@ -418,7 +432,6 @@ macro_rules! bdk_blockchain_tests {
             }
 
             #[test]
-            #[serial]
             fn test_sync_before_and_after_receive() {
                 let (wallet, descriptors, mut test_client) = init_single_sig();
 
@@ -436,7 +449,6 @@ macro_rules! bdk_blockchain_tests {
             }
 
             #[test]
-            #[serial]
             fn test_sync_multiple_outputs_same_tx() {
                 let (wallet, descriptors, mut test_client) = init_single_sig();
 
@@ -458,7 +470,6 @@ macro_rules! bdk_blockchain_tests {
             }
 
             #[test]
-            #[serial]
             fn test_sync_receive_multi() {
                 let (wallet, descriptors, mut test_client) = init_single_sig();
 
@@ -477,7 +488,6 @@ macro_rules! bdk_blockchain_tests {
             }
 
             #[test]
-            #[serial]
             fn test_sync_address_reuse() {
                 let (wallet, descriptors, mut test_client) = init_single_sig();
 
@@ -497,7 +507,6 @@ macro_rules! bdk_blockchain_tests {
             }
 
             #[test]
-            #[serial]
             fn test_sync_receive_rbf_replaced() {
                 let (wallet, descriptors, mut test_client) = init_single_sig();
 
@@ -536,7 +545,6 @@ macro_rules! bdk_blockchain_tests {
             // doesn't work for some reason.
             #[cfg(not(feature = "esplora"))]
             #[test]
-            #[serial]
             fn test_sync_reorg_block() {
                 let (wallet, descriptors, mut test_client) = init_single_sig();
 
@@ -567,7 +575,6 @@ macro_rules! bdk_blockchain_tests {
             }
 
             #[test]
-            #[serial]
             fn test_sync_after_send() {
                 let (wallet, descriptors, mut test_client) = init_single_sig();
                 println!("{}", descriptors.0);
@@ -588,7 +595,6 @@ macro_rules! bdk_blockchain_tests {
                 let tx = psbt.extract_tx();
                 println!("{}", bitcoin::consensus::encode::serialize_hex(&tx));
                 wallet.broadcast(tx).unwrap();
-
                 wallet.sync(noop_progress(), None).unwrap();
                 assert_eq!(wallet.get_balance().unwrap(), details.received, "incorrect balance after send");
 
@@ -597,7 +603,6 @@ macro_rules! bdk_blockchain_tests {
             }
 
             #[test]
-            #[serial]
             fn test_update_confirmation_time_after_generate() {
                 let (wallet, descriptors, mut test_client) = init_single_sig();
                 println!("{}", descriptors.0);
@@ -623,9 +628,7 @@ macro_rules! bdk_blockchain_tests {
 
             }
 
-
             #[test]
-            #[serial]
             fn test_sync_outgoing_from_scratch() {
                 let (wallet, descriptors, mut test_client) = init_single_sig();
                 let node_addr = test_client.get_node_address(None);
@@ -648,7 +651,7 @@ macro_rules! bdk_blockchain_tests {
                 assert_eq!(wallet.get_balance().unwrap(), details.received, "incorrect balance after receive");
 
                 // empty wallet
-                let wallet = get_wallet_from_descriptors(&descriptors);
+                let wallet = get_wallet_from_descriptors(&descriptors, &test_client);
 
                 #[cfg(feature = "rpc")]  // rpc cannot see mempool tx before importmulti
                 test_client.generate(1, Some(node_addr));
@@ -667,7 +670,6 @@ macro_rules! bdk_blockchain_tests {
             }
 
             #[test]
-            #[serial]
             fn test_sync_long_change_chain() {
                 let (wallet, descriptors, mut test_client) = init_single_sig();
                 let node_addr = test_client.get_node_address(None);
@@ -698,7 +700,7 @@ macro_rules! bdk_blockchain_tests {
 
                 // empty wallet
 
-                let wallet = get_wallet_from_descriptors(&descriptors);
+                let wallet = get_wallet_from_descriptors(&descriptors, &test_client);
 
                 #[cfg(feature = "rpc")]  // rpc cannot see mempool tx before importmulti
                 test_client.generate(1, Some(node_addr));
@@ -709,7 +711,6 @@ macro_rules! bdk_blockchain_tests {
             }
 
             #[test]
-            #[serial]
             fn test_sync_bump_fee_basic() {
                 let (wallet, descriptors, mut test_client) = init_single_sig();
                 let node_addr = test_client.get_node_address(None);
@@ -745,7 +746,6 @@ macro_rules! bdk_blockchain_tests {
             }
 
             #[test]
-            #[serial]
             fn test_sync_bump_fee_remove_change() {
                 let (wallet, descriptors, mut test_client) = init_single_sig();
                 let node_addr = test_client.get_node_address(None);
@@ -781,7 +781,6 @@ macro_rules! bdk_blockchain_tests {
             }
 
             #[test]
-            #[serial]
             fn test_sync_bump_fee_add_input_simple() {
                 let (wallet, descriptors, mut test_client) = init_single_sig();
                 let node_addr = test_client.get_node_address(None);
@@ -815,7 +814,6 @@ macro_rules! bdk_blockchain_tests {
             }
 
             #[test]
-            #[serial]
             fn test_sync_bump_fee_add_input_no_change() {
                 let (wallet, descriptors, mut test_client) = init_single_sig();
                 let node_addr = test_client.get_node_address(None);
@@ -852,7 +850,6 @@ macro_rules! bdk_blockchain_tests {
             }
 
             #[test]
-            #[serial]
             fn test_sync_receive_coinbase() {
                 let (wallet, _, mut test_client) = init_single_sig();
 
@@ -875,5 +872,10 @@ macro_rules! bdk_blockchain_tests {
                 assert!(wallet.get_balance().unwrap() > 0, "incorrect balance after receiving coinbase");
             }
         }
-    }
+    };
+
+    ( fn $fn_name:ident ($( $tt:tt )+) -> $blockchain:ty $block:block) => {
+        compile_error!(concat!("Invalid arguments `", stringify!($($tt)*), "` in the blockchain tests fn."));
+        compile_error!("Only the exact `&TestClient` type is supported, **without** any leading path items.");
+    };
 }

src/testutils/mod.rs

@@ -10,6 +10,7 @@
 // licenses.
 #![allow(missing_docs)]
 
+#[cfg(test)]
 #[cfg(feature = "test-blockchains")]
 pub mod blockchain_tests;
 
@@ -99,8 +100,8 @@ impl TranslateDescriptor for Descriptor<DescriptorPublicKey> {
 #[macro_export]
 macro_rules! testutils {
     ( @external $descriptors:expr, $child:expr ) => ({
-        use bitcoin::secp256k1::Secp256k1;
-        use miniscript::descriptor::{Descriptor, DescriptorPublicKey, DescriptorTrait};
+        use $crate::bitcoin::secp256k1::Secp256k1;
+        use $crate::miniscript::descriptor::{Descriptor, DescriptorPublicKey, DescriptorTrait};
 
         use $crate::testutils::TranslateDescriptor;
 
@@ -110,15 +111,15 @@ macro_rules! testutils {
         parsed.derive_translated(&secp, $child).address(bitcoin::Network::Regtest).expect("No address form")
     });
     ( @internal $descriptors:expr, $child:expr ) => ({
-        use bitcoin::secp256k1::Secp256k1;
-        use miniscript::descriptor::{Descriptor, DescriptorPublicKey, DescriptorTrait};
+        use $crate::bitcoin::secp256k1::Secp256k1;
+        use $crate::miniscript::descriptor::{Descriptor, DescriptorPublicKey, DescriptorTrait};
 
         use $crate::testutils::TranslateDescriptor;
 
         let secp = Secp256k1::new();
 
         let parsed = Descriptor::<DescriptorPublicKey>::parse_descriptor(&secp, &$descriptors.1.expect("Missing internal descriptor")).expect("Failed to parse descriptor in `testutils!(@internal)`").0;
-        parsed.derive_translated(&secp, $child).address(bitcoin::Network::Regtest).expect("No address form")
+        parsed.derive_translated(&secp, $child).address($crate::bitcoin::Network::Regtest).expect("No address form")
     });
     ( @e $descriptors:expr, $child:expr ) => ({ testutils!(@external $descriptors, $child) });
     ( @i $descriptors:expr, $child:expr ) => ({ testutils!(@internal $descriptors, $child) });
@@ -144,8 +145,8 @@ macro_rules! testutils {
         let mut seed = [0u8; 32];
         rand::thread_rng().fill(&mut seed[..]);
 
-        let key = bitcoin::util::bip32::ExtendedPrivKey::new_master(
-            bitcoin::Network::Testnet,
+        let key = $crate::bitcoin::util::bip32::ExtendedPrivKey::new_master(
+            $crate::bitcoin::Network::Testnet,
             &seed,
         );
 
@@ -157,13 +158,13 @@ macro_rules! testutils {
     ( @generate_wif ) => ({
         use rand::Rng;
 
-        let mut key = [0u8; bitcoin::secp256k1::constants::SECRET_KEY_SIZE];
+        let mut key = [0u8; $crate::bitcoin::secp256k1::constants::SECRET_KEY_SIZE];
         rand::thread_rng().fill(&mut key[..]);
 
-        (bitcoin::PrivateKey {
+        ($crate::bitcoin::PrivateKey {
             compressed: true,
-            network: bitcoin::Network::Testnet,
-            key: bitcoin::secp256k1::SecretKey::from_slice(&key).unwrap(),
+            network: $crate::bitcoin::Network::Testnet,
+            key: $crate::bitcoin::secp256k1::SecretKey::from_slice(&key).unwrap(),
         }.to_string(), None::<String>, None::<String>)
     });
 
@@ -180,8 +181,8 @@ macro_rules! testutils {
     ( @descriptors ( $external_descriptor:expr ) $( ( $internal_descriptor:expr ) )? $( ( @keys $( $keys:tt )* ) )* ) => ({
         use std::str::FromStr;
         use std::collections::HashMap;
-        use miniscript::descriptor::Descriptor;
-        use miniscript::TranslatePk;
+        use $crate::miniscript::descriptor::Descriptor;
+        use $crate::miniscript::TranslatePk;
 
         #[allow(unused_assignments, unused_mut)]
         let mut keys: HashMap<&'static str, (String, Option<String>, Option<String>)> = HashMap::new();

src/types.rs

@@ -10,6 +10,7 @@
 // licenses.
 
 use std::convert::AsRef;
+use std::ops::Sub;
 
 use bitcoin::blockdata::transaction::{OutPoint, Transaction, TxOut};
 use bitcoin::{hash_types::Txid, util::psbt};
@@ -65,10 +66,31 @@ impl FeeRate {
         FeeRate(1.0)
     }
 
+    /// Calculate fee rate from `fee` and weight units (`wu`).
+    pub fn from_wu(fee: u64, wu: usize) -> FeeRate {
+        Self::from_vb(fee, wu.vbytes())
+    }
+
+    /// Calculate fee rate from `fee` and `vbytes`.
+    pub fn from_vb(fee: u64, vbytes: usize) -> FeeRate {
+        let rate = fee as f32 / vbytes as f32;
+        Self::from_sat_per_vb(rate)
+    }
+
     /// Return the value as satoshi/vbyte
     pub fn as_sat_vb(&self) -> f32 {
         self.0
     }
+
+    /// Calculate absolute fee in Satoshis using size in weight units.
+    pub fn fee_wu(&self, wu: usize) -> u64 {
+        self.fee_vb(wu.vbytes())
+    }
+
+    /// Calculate absolute fee in Satoshis using size in virtual bytes.
+    pub fn fee_vb(&self, vbytes: usize) -> u64 {
+        (self.as_sat_vb() * vbytes as f32).ceil() as u64
+    }
 }
 
 impl std::default::Default for FeeRate {
@@ -77,6 +99,27 @@ impl std::default::Default for FeeRate {
     }
 }
 
+impl Sub for FeeRate {
+    type Output = Self;
+
+    fn sub(self, other: FeeRate) -> Self::Output {
+        FeeRate(self.0 - other.0)
+    }
+}
+
+/// Trait implemented by types that can be used to measure weight units.
+pub trait Vbytes {
+    /// Convert weight units to virtual bytes.
+    fn vbytes(self) -> usize;
+}
+
+impl Vbytes for usize {
+    fn vbytes(self) -> usize {
+        // ref: https://github.com/bitcoin/bips/blob/master/bip-0141.mediawiki#transaction-size-calculations
+        (self as f32 / 4.0).ceil() as usize
+    }
+}
+
 /// An unspent output owned by a [`Wallet`].
 ///
 /// [`Wallet`]: crate::Wallet
@@ -160,11 +203,23 @@ pub struct TransactionDetails {
     pub received: u64,
     /// Sent value (sats)
     pub sent: u64,
-    /// Fee value (sats) if available
+    /// Fee value (sats) if available.
+    /// The availability of the fee depends on the backend. It's never `None` with an Electrum
+    /// Server backend, but it could be `None` with a Bitcoin RPC node without txindex that receive
+    /// funds while offline.
     pub fee: Option<u64>,
     /// If the transaction is confirmed, contains height and timestamp of the block containing the
     /// transaction, unconfirmed transaction contains `None`.
     pub confirmation_time: Option<ConfirmationTime>,
+    /// Whether the tx has been verified against the consensus rules
+    ///
+    /// Confirmed txs are considered "verified" by default, while unconfirmed txs are checked to
+    /// ensure an unstrusted [`Blockchain`](crate::blockchain::Blockchain) backend can't trick the
+    /// wallet into using an invalid tx as an RBF template.
+    ///
+    /// The check is only perfomed when the `verify` feature is enabled.
+    #[serde(default = "bool::default")] // default to `false` if not specified
+    pub verified: bool,
 }
 
 /// Block height and timestamp of the block containing the confirmed transaction

src/wallet/address_validator.rs

@@ -115,8 +115,8 @@ mod test {
     use std::sync::Arc;
 
     use super::*;
-    use crate::wallet::test::{get_funded_wallet, get_test_wpkh};
     use crate::wallet::AddressIndex::New;
+    use crate::wallet::{get_funded_wallet, test::get_test_wpkh};
 
     #[derive(Debug)]
     struct TestValidator;

src/wallet/coin_selection.rs

@@ -26,7 +26,7 @@
 //! ```
 //! # use std::str::FromStr;
 //! # use bitcoin::*;
-//! # use bdk::wallet::coin_selection::*;
+//! # use bdk::wallet::{self, coin_selection::*};
 //! # use bdk::database::Database;
 //! # use bdk::*;
 //! # const TXIN_BASE_WEIGHT: usize = (32 + 4 + 4 + 1) * 4;
@@ -41,7 +41,7 @@
 //!         optional_utxos: Vec<WeightedUtxo>,
 //!         fee_rate: FeeRate,
 //!         amount_needed: u64,
-//!         fee_amount: f32,
+//!         fee_amount: u64,
 //!     ) -> Result<CoinSelectionResult, bdk::Error> {
 //!         let mut selected_amount = 0;
 //!         let mut additional_weight = 0;
@@ -57,9 +57,8 @@
 //!                 },
 //!             )
 //!             .collect::<Vec<_>>();
-//!         let additional_fees = additional_weight as f32 * fee_rate.as_sat_vb() / 4.0;
-//!         let amount_needed_with_fees =
-//!             (fee_amount + additional_fees).ceil() as u64 + amount_needed;
+//!         let additional_fees = fee_rate.fee_wu(additional_weight);
+//!         let amount_needed_with_fees = (fee_amount + additional_fees) + amount_needed;
 //!         if amount_needed_with_fees > selected_amount {
 //!             return Err(bdk::Error::InsufficientFunds {
 //!                 needed: amount_needed_with_fees,
@@ -117,7 +116,7 @@ pub struct CoinSelectionResult {
     /// List of outputs selected for use as inputs
     pub selected: Vec<Utxo>,
     /// Total fee amount in satoshi
-    pub fee_amount: f32,
+    pub fee_amount: u64,
 }
 
 impl CoinSelectionResult {
@@ -164,7 +163,7 @@ pub trait CoinSelectionAlgorithm<D: Database>: std::fmt::Debug {
         optional_utxos: Vec<WeightedUtxo>,
         fee_rate: FeeRate,
         amount_needed: u64,
-        fee_amount: f32,
+        fee_amount: u64,
     ) -> Result<CoinSelectionResult, Error>;
 }
 
@@ -183,10 +182,8 @@ impl<D: Database> CoinSelectionAlgorithm<D> for LargestFirstCoinSelection {
         mut optional_utxos: Vec<WeightedUtxo>,
         fee_rate: FeeRate,
         amount_needed: u64,
-        mut fee_amount: f32,
+        mut fee_amount: u64,
     ) -> Result<CoinSelectionResult, Error> {
-        let calc_fee_bytes = |wu| (wu as f32) * fee_rate.as_sat_vb() / 4.0;
-
         log::debug!(
             "amount_needed = `{}`, fee_amount = `{}`, fee_rate = `{:?}`",
             amount_needed,
@@ -211,9 +208,9 @@ impl<D: Database> CoinSelectionAlgorithm<D> for LargestFirstCoinSelection {
             .scan(
                 (&mut selected_amount, &mut fee_amount),
                 |(selected_amount, fee_amount), (must_use, weighted_utxo)| {
-                    if must_use || **selected_amount < amount_needed + (fee_amount.ceil() as u64) {
+                    if must_use || **selected_amount < amount_needed + **fee_amount {
                         **fee_amount +=
-                            calc_fee_bytes(TXIN_BASE_WEIGHT + weighted_utxo.satisfaction_weight);
+                            fee_rate.fee_wu(TXIN_BASE_WEIGHT + weighted_utxo.satisfaction_weight);
                         **selected_amount += weighted_utxo.utxo.txout().value;
 
                         log::debug!(
@@ -230,7 +227,7 @@ impl<D: Database> CoinSelectionAlgorithm<D> for LargestFirstCoinSelection {
             )
             .collect::<Vec<_>>();
 
-        let amount_needed_with_fees = amount_needed + (fee_amount.ceil() as u64);
+        let amount_needed_with_fees = amount_needed + fee_amount;
         if selected_amount < amount_needed_with_fees {
             return Err(Error::InsufficientFunds {
                 needed: amount_needed_with_fees,
@@ -250,16 +247,15 @@ impl<D: Database> CoinSelectionAlgorithm<D> for LargestFirstCoinSelection {
 struct OutputGroup {
     weighted_utxo: WeightedUtxo,
     // Amount of fees for spending a certain utxo, calculated using a certain FeeRate
-    fee: f32,
+    fee: u64,
     // The effective value of the UTXO, i.e., the utxo value minus the fee for spending it
     effective_value: i64,
 }
 
 impl OutputGroup {
     fn new(weighted_utxo: WeightedUtxo, fee_rate: FeeRate) -> Self {
-        let fee = (TXIN_BASE_WEIGHT + weighted_utxo.satisfaction_weight) as f32 / 4.0
-            * fee_rate.as_sat_vb();
-        let effective_value = weighted_utxo.utxo.txout().value as i64 - fee.ceil() as i64;
+        let fee = fee_rate.fee_wu(TXIN_BASE_WEIGHT + weighted_utxo.satisfaction_weight);
+        let effective_value = weighted_utxo.utxo.txout().value as i64 - fee as i64;
         OutputGroup {
             weighted_utxo,
             fee,
@@ -302,7 +298,7 @@ impl<D: Database> CoinSelectionAlgorithm<D> for BranchAndBoundCoinSelection {
         optional_utxos: Vec<WeightedUtxo>,
         fee_rate: FeeRate,
         amount_needed: u64,
-        fee_amount: f32,
+        fee_amount: u64,
     ) -> Result<CoinSelectionResult, Error> {
         // Mapping every (UTXO, usize) to an output group
         let required_utxos: Vec<OutputGroup> = required_utxos
@@ -324,7 +320,7 @@ impl<D: Database> CoinSelectionAlgorithm<D> for BranchAndBoundCoinSelection {
             .iter()
             .fold(0, |acc, x| acc + x.effective_value);
 
-        let actual_target = fee_amount.ceil() as u64 + amount_needed;
+        let actual_target = fee_amount + amount_needed;
         let cost_of_change = self.size_of_change as f32 * fee_rate.as_sat_vb();
 
         let expected = (curr_available_value + curr_value)
@@ -344,6 +340,14 @@ impl<D: Database> CoinSelectionAlgorithm<D> for BranchAndBoundCoinSelection {
             .try_into()
             .expect("Bitcoin amount to fit into i64");
 
+        if curr_value > actual_target {
+            return Ok(BranchAndBoundCoinSelection::calculate_cs_result(
+                vec![],
+                required_utxos,
+                fee_amount,
+            ));
+        }
+
         Ok(self
             .bnb(
                 required_utxos.clone(),
@@ -377,7 +381,7 @@ impl BranchAndBoundCoinSelection {
         mut curr_value: i64,
         mut curr_available_value: i64,
         actual_target: i64,
-        fee_amount: f32,
+        fee_amount: u64,
         cost_of_change: f32,
     ) -> Result<CoinSelectionResult, Error> {
         // current_selection[i] will contain true if we are using optional_utxos[i],
@@ -485,7 +489,7 @@ impl BranchAndBoundCoinSelection {
         mut optional_utxos: Vec<OutputGroup>,
         curr_value: i64,
         actual_target: i64,
-        fee_amount: f32,
+        fee_amount: u64,
     ) -> CoinSelectionResult {
         #[cfg(not(test))]
         optional_utxos.shuffle(&mut thread_rng());
@@ -514,10 +518,10 @@ impl BranchAndBoundCoinSelection {
     fn calculate_cs_result(
         mut selected_utxos: Vec<OutputGroup>,
         mut required_utxos: Vec<OutputGroup>,
-        mut fee_amount: f32,
+        mut fee_amount: u64,
     ) -> CoinSelectionResult {
         selected_utxos.append(&mut required_utxos);
-        fee_amount += selected_utxos.iter().map(|u| u.fee).sum::<f32>();
+        fee_amount += selected_utxos.iter().map(|u| u.fee).sum::<u64>();
         let selected = selected_utxos
             .into_iter()
             .map(|u| u.weighted_utxo.utxo)
@@ -539,6 +543,7 @@ mod test {
     use super::*;
     use crate::database::MemoryDatabase;
     use crate::types::*;
+    use crate::wallet::Vbytes;
 
     use rand::rngs::StdRng;
     use rand::seq::SliceRandom;
@@ -546,52 +551,33 @@ mod test {
 
     const P2WPKH_WITNESS_SIZE: usize = 73 + 33 + 2;
 
-    const FEE_AMOUNT: f32 = 50.0;
+    const FEE_AMOUNT: u64 = 50;
+
+    fn utxo(value: u64, index: u32) -> WeightedUtxo {
+        assert!(index < 10);
+        let outpoint = OutPoint::from_str(&format!(
+            "000000000000000000000000000000000000000000000000000000000000000{}:0",
+            index
+        ))
+        .unwrap();
+        WeightedUtxo {
+            satisfaction_weight: P2WPKH_WITNESS_SIZE,
+            utxo: Utxo::Local(LocalUtxo {
+                outpoint,
+                txout: TxOut {
+                    value,
+                    script_pubkey: Script::new(),
+                },
+                keychain: KeychainKind::External,
+            }),
+        }
+    }
 
     fn get_test_utxos() -> Vec<WeightedUtxo> {
         vec![
-            WeightedUtxo {
-                satisfaction_weight: P2WPKH_WITNESS_SIZE,
-                utxo: Utxo::Local(LocalUtxo {
-                    outpoint: OutPoint::from_str(
-                        "0000000000000000000000000000000000000000000000000000000000000000:0",
-                    )
-                    .unwrap(),
-                    txout: TxOut {
-                        value: 100_000,
-                        script_pubkey: Script::new(),
-                    },
-                    keychain: KeychainKind::External,
-                }),
-            },
-            WeightedUtxo {
-                satisfaction_weight: P2WPKH_WITNESS_SIZE,
-                utxo: Utxo::Local(LocalUtxo {
-                    outpoint: OutPoint::from_str(
-                        "0000000000000000000000000000000000000000000000000000000000000001:0",
-                    )
-                    .unwrap(),
-                    txout: TxOut {
-                        value: FEE_AMOUNT as u64 - 40,
-                        script_pubkey: Script::new(),
-                    },
-                    keychain: KeychainKind::External,
-                }),
-            },
-            WeightedUtxo {
-                satisfaction_weight: P2WPKH_WITNESS_SIZE,
-                utxo: Utxo::Local(LocalUtxo {
-                    outpoint: OutPoint::from_str(
-                        "0000000000000000000000000000000000000000000000000000000000000002:0",
-                    )
-                    .unwrap(),
-                    txout: TxOut {
-                        value: 200_000,
-                        script_pubkey: Script::new(),
-                    },
-                    keychain: KeychainKind::Internal,
-                }),
-            },
+            utxo(100_000, 0),
+            utxo(FEE_AMOUNT as u64 - 40, 1),
+            utxo(200_000, 2),
         ]
     }
 
@@ -655,13 +641,13 @@ mod test {
                 vec![],
                 FeeRate::from_sat_per_vb(1.0),
                 250_000,
-                50.0,
+                FEE_AMOUNT,
             )
             .unwrap();
 
         assert_eq!(result.selected.len(), 3);
         assert_eq!(result.selected_amount(), 300_010);
-        assert!((result.fee_amount - 254.0).abs() < f32::EPSILON);
+        assert_eq!(result.fee_amount, 254)
     }
 
     #[test]
@@ -676,13 +662,13 @@ mod test {
                 vec![],
                 FeeRate::from_sat_per_vb(1.0),
                 20_000,
-                50.0,
+                FEE_AMOUNT,
             )
             .unwrap();
 
         assert_eq!(result.selected.len(), 3);
         assert_eq!(result.selected_amount(), 300_010);
-        assert!((result.fee_amount - 254.0).abs() < f32::EPSILON);
+        assert_eq!(result.fee_amount, 254);
     }
 
     #[test]
@@ -697,13 +683,13 @@ mod test {
                 utxos,
                 FeeRate::from_sat_per_vb(1.0),
                 20_000,
-                50.0,
+                FEE_AMOUNT,
             )
             .unwrap();
 
         assert_eq!(result.selected.len(), 1);
         assert_eq!(result.selected_amount(), 200_000);
-        assert!((result.fee_amount - 118.0).abs() < f32::EPSILON);
+        assert_eq!(result.fee_amount, 118);
     }
 
     #[test]
@@ -719,7 +705,7 @@ mod test {
                 utxos,
                 FeeRate::from_sat_per_vb(1.0),
                 500_000,
-                50.0,
+                FEE_AMOUNT,
             )
             .unwrap();
     }
@@ -737,7 +723,7 @@ mod test {
                 utxos,
                 FeeRate::from_sat_per_vb(1000.0),
                 250_000,
-                50.0,
+                FEE_AMOUNT,
             )
             .unwrap();
     }
@@ -757,13 +743,13 @@ mod test {
                 utxos,
                 FeeRate::from_sat_per_vb(1.0),
                 250_000,
-                50.0,
+                FEE_AMOUNT,
             )
             .unwrap();
 
         assert_eq!(result.selected.len(), 3);
         assert_eq!(result.selected_amount(), 300_000);
-        assert!((result.fee_amount - 254.0).abs() < f32::EPSILON);
+        assert_eq!(result.fee_amount, 254);
     }
 
     #[test]
@@ -784,7 +770,7 @@ mod test {
 
         assert_eq!(result.selected.len(), 3);
         assert_eq!(result.selected_amount(), 300_010);
-        assert!((result.fee_amount - 254.0).abs() < f32::EPSILON);
+        assert_eq!(result.fee_amount, 254);
     }
 
     #[test]
@@ -805,7 +791,38 @@ mod test {
 
         assert_eq!(result.selected.len(), 3);
         assert_eq!(result.selected_amount(), 300010);
-        assert!((result.fee_amount - 254.0).abs() < f32::EPSILON);
+        assert_eq!(result.fee_amount, 254);
+    }
+
+    #[test]
+    fn test_bnb_coin_selection_required_not_enough() {
+        let utxos = get_test_utxos();
+        let database = MemoryDatabase::default();
+
+        let required = vec![utxos[0].clone()];
+        let mut optional = utxos[1..].to_vec();
+        optional.push(utxo(500_000, 3));
+
+        // Defensive assertions, for sanity and in case someone changes the test utxos vector.
+        let amount: u64 = required.iter().map(|u| u.utxo.txout().value).sum();
+        assert_eq!(amount, 100_000);
+        let amount: u64 = optional.iter().map(|u| u.utxo.txout().value).sum();
+        assert!(amount > 150_000);
+
+        let result = BranchAndBoundCoinSelection::default()
+            .coin_select(
+                &database,
+                required,
+                optional,
+                FeeRate::from_sat_per_vb(1.0),
+                150_000,
+                FEE_AMOUNT,
+            )
+            .unwrap();
+
+        assert_eq!(result.selected.len(), 3);
+        assert_eq!(result.selected_amount(), 300_010);
+        assert!((result.fee_amount as f32 - 254.0).abs() < f32::EPSILON);
     }
 
     #[test]
@@ -821,7 +838,7 @@ mod test {
                 utxos,
                 FeeRate::from_sat_per_vb(1.0),
                 500_000,
-                50.0,
+                FEE_AMOUNT,
             )
             .unwrap();
     }
@@ -839,7 +856,7 @@ mod test {
                 utxos,
                 FeeRate::from_sat_per_vb(1000.0),
                 250_000,
-                50.0,
+                FEE_AMOUNT,
             )
             .unwrap();
     }
@@ -856,15 +873,15 @@ mod test {
                 utxos,
                 FeeRate::from_sat_per_vb(1.0),
                 99932, // first utxo's effective value
-                0.0,
+                0,
             )
             .unwrap();
 
         assert_eq!(result.selected.len(), 1);
         assert_eq!(result.selected_amount(), 100_000);
-        let input_size = (TXIN_BASE_WEIGHT as f32) / 4.0 + P2WPKH_WITNESS_SIZE as f32 / 4.0;
+        let input_size = (TXIN_BASE_WEIGHT + P2WPKH_WITNESS_SIZE).vbytes();
         let epsilon = 0.5;
-        assert!((1.0 - (result.fee_amount / input_size)).abs() < epsilon);
+        assert!((1.0 - (result.fee_amount as f32 / input_size as f32)).abs() < epsilon);
     }
 
     #[test]
@@ -883,7 +900,7 @@ mod test {
                     optional_utxos,
                     FeeRate::from_sat_per_vb(0.0),
                     target_amount,
-                    0.0,
+                    0,
                 )
                 .unwrap();
             assert_eq!(result.selected_amount(), target_amount);
@@ -910,7 +927,7 @@ mod test {
                 0,
                 curr_available_value,
                 20_000,
-                50.0,
+                FEE_AMOUNT,
                 cost_of_change,
             )
             .unwrap();
@@ -937,7 +954,7 @@ mod test {
                 0,
                 curr_available_value,
                 20_000,
-                50.0,
+                FEE_AMOUNT,
                 cost_of_change,
             )
             .unwrap();
@@ -949,7 +966,6 @@ mod test {
         let fee_rate = FeeRate::from_sat_per_vb(1.0);
         let size_of_change = 31;
         let cost_of_change = size_of_change as f32 * fee_rate.as_sat_vb();
-        let fee_amount = 50.0;
 
         let utxos: Vec<_> = generate_same_value_utxos(50_000, 10)
             .into_iter()
@@ -971,12 +987,12 @@ mod test {
                 curr_value,
                 curr_available_value,
                 target_amount,
-                fee_amount,
+                FEE_AMOUNT,
                 cost_of_change,
             )
             .unwrap();
-        assert!((result.fee_amount - 186.0).abs() < f32::EPSILON);
         assert_eq!(result.selected_amount(), 100_000);
+        assert_eq!(result.fee_amount, 186);
     }
 
     // TODO: bnb() function should be optimized, and this test should be done with more utxos
@@ -1008,7 +1024,7 @@ mod test {
                     curr_value,
                     curr_available_value,
                     target_amount,
-                    0.0,
+                    0,
                     0.0,
                 )
                 .unwrap();
@@ -1034,12 +1050,10 @@ mod test {
             utxos,
             0,
             target_amount as i64,
-            50.0,
+            FEE_AMOUNT,
         );
 
         assert!(result.selected_amount() > target_amount);
-        assert!(
-            (result.fee_amount - (50.0 + result.selected.len() as f32 * 68.0)).abs() < f32::EPSILON
-        );
+        assert_eq!(result.fee_amount, (50 + result.selected.len() * 68) as u64);
     }
 }

src/wallet/export.rs

@@ -230,6 +230,7 @@ mod test {
                 timestamp: 12345678,
                 height: 5000,
             }),
+            verified: true,
         })
         .unwrap();
 

src/wallet/mod.rs

@@ -18,6 +18,7 @@ use std::collections::HashMap;
 use std::collections::{BTreeMap, HashSet};
 use std::fmt;
 use std::ops::{Deref, DerefMut};
+use std::str::FromStr;
 use std::sync::Arc;
 
 use bitcoin::secp256k1::Secp256k1;
@@ -42,6 +43,9 @@ pub mod signer;
 pub mod time;
 pub mod tx_builder;
 pub(crate) mod utils;
+#[cfg(feature = "verify")]
+#[cfg_attr(docsrs, doc(cfg(feature = "verify")))]
+pub mod verify;
 
 pub use utils::IsDust;
 
@@ -52,6 +56,7 @@ use tx_builder::{BumpFee, CreateTx, FeePolicy, TxBuilder, TxParams};
 use utils::{check_nlocktime, check_nsequence_rbf, After, Older, SecpCtx, DUST_LIMIT_SATOSHI};
 
 use crate::blockchain::{Blockchain, Progress};
+use crate::database::memory::MemoryDatabase;
 use crate::database::{BatchDatabase, BatchOperations, DatabaseUtils};
 use crate::descriptor::derived::AsDerived;
 use crate::descriptor::policy::BuildSatisfaction;
@@ -63,6 +68,7 @@ use crate::descriptor::{
 use crate::error::Error;
 use crate::psbt::PsbtUtils;
 use crate::signer::SignerError;
+use crate::testutils;
 use crate::types::*;
 
 const CACHE_ADDR_BATCH_SIZE: u32 = 100;
@@ -164,6 +170,11 @@ where
             secp,
         })
     }
+
+    /// Get the Bitcoin network the wallet is using.
+    pub fn network(&self) -> Network {
+        self.network
+    }
 }
 
 /// The address index selection strategy to use to derived an address from the wallet's external
@@ -312,7 +323,7 @@ where
 
     /// Return the list of unspent outputs of this wallet
     ///
-    /// Note that this methods only operate on the internal database, which first needs to be
+    /// Note that this method only operates on the internal database, which first needs to be
     /// [`Wallet::sync`] manually.
     pub fn list_unspent(&self) -> Result<Vec<LocalUtxo>, Error> {
         self.database.borrow().iter_utxos()
@@ -324,6 +335,21 @@ where
         self.database.borrow().get_utxo(&outpoint)
     }
 
+    /// Return a single transactions made and received by the wallet
+    ///
+    /// Optionally fill the [`TransactionDetails::transaction`] field with the raw transaction if
+    /// `include_raw` is `true`.
+    ///
+    /// Note that this method only operates on the internal database, which first needs to be
+    /// [`Wallet::sync`] manually.
+    pub fn get_tx(
+        &self,
+        txid: &Txid,
+        include_raw: bool,
+    ) -> Result<Option<TransactionDetails>, Error> {
+        self.database.borrow().get_tx(txid, include_raw)
+    }
+
     /// Return the list of transactions made and received by the wallet
     ///
     /// Optionally fill the [`TransactionDetails::transaction`] field with the raw transaction if
@@ -540,7 +566,7 @@ where
                         });
                     }
                 }
-                (FeeRate::from_sat_per_vb(0.0), *fee as f32)
+                (FeeRate::from_sat_per_vb(0.0), *fee)
             }
             FeePolicy::FeeRate(rate) => {
                 if let Some(previous_fee) = params.bumping_fee {
@@ -551,7 +577,7 @@ where
                         });
                     }
                 }
-                (*rate, 0.0)
+                (*rate, 0)
             }
         };
 
@@ -562,21 +588,6 @@ where
             output: vec![],
         };
 
-        let recipients = match &params.single_recipient {
-            Some(recipient) => vec![(recipient, 0)],
-            None => params.recipients.iter().map(|(r, v)| (r, *v)).collect(),
-        };
-        if params.single_recipient.is_some()
-            && !params.manually_selected_only
-            && !params.drain_wallet
-            && params.bumping_fee.is_none()
-        {
-            return Err(Error::SingleRecipientNoInputs);
-        }
-        if recipients.is_empty() {
-            return Err(Error::NoRecipients);
-        }
-
         if params.manually_selected_only && params.utxos.is_empty() {
             return Err(Error::NoUtxosSelected);
         }
@@ -585,15 +596,14 @@ where
         let mut outgoing: u64 = 0;
         let mut received: u64 = 0;
 
-        let calc_fee_bytes = |wu| (wu as f32) * fee_rate.as_sat_vb() / 4.0;
-        fee_amount += calc_fee_bytes(tx.get_weight());
+        fee_amount += fee_rate.fee_wu(tx.get_weight());
 
-        for (index, (script_pubkey, satoshi)) in recipients.into_iter().enumerate() {
-            let value = match params.single_recipient {
-                Some(_) => 0,
-                None if satoshi.is_dust() => return Err(Error::OutputBelowDustLimit(index)),
-                None => satoshi,
-            };
+        let recipients = params.recipients.iter().map(|(r, v)| (r, *v));
+
+        for (index, (script_pubkey, value)) in recipients.enumerate() {
+            if value.is_dust() {
+                return Err(Error::OutputBelowDustLimit(index));
+            }
 
             if self.is_mine(script_pubkey)? {
                 received += value;
@@ -603,7 +613,7 @@ where
                 script_pubkey: script_pubkey.clone(),
                 value,
             };
-            fee_amount += calc_fee_bytes(serialize(&new_out).len() * 4);
+            fee_amount += fee_rate.fee_vb(serialize(&new_out).len());
 
             tx.output.push(new_out);
 
@@ -648,54 +658,46 @@ where
             })
             .collect();
 
-        // prepare the change output
-        let change_output = match params.single_recipient {
-            Some(_) => None,
-            None => {
-                let change_script = self.get_change_address()?;
-                let change_output = TxOut {
-                    script_pubkey: change_script,
-                    value: 0,
-                };
+        // prepare the drain output
+        let mut drain_output = {
+            let script_pubkey = match params.drain_to {
+                Some(ref drain_recipient) => drain_recipient.clone(),
+                None => self.get_change_address()?,
+            };
 
-                // take the change into account for fees
-                fee_amount += calc_fee_bytes(serialize(&change_output).len() * 4);
-                Some(change_output)
+            TxOut {
+                script_pubkey,
+                value: 0,
             }
         };
-        let mut fee_amount = fee_amount.ceil() as u64;
-        let change_val = (coin_selection.selected_amount() - outgoing).saturating_sub(fee_amount);
 
-        match change_output {
-            None if change_val.is_dust() => {
-                // single recipient, but the only output would be below dust limit
-                // TODO: or OutputBelowDustLimit?
-                return Err(Error::InsufficientFunds {
-                    needed: DUST_LIMIT_SATOSHI,
-                    available: change_val,
-                });
-            }
-            Some(_) if change_val.is_dust() => {
-                // skip the change output because it's dust -- just include it in the fee.
-                fee_amount += change_val;
-            }
-            Some(mut change_output) => {
-                change_output.value = change_val;
-                received += change_val;
+        fee_amount += fee_rate.fee_vb(serialize(&drain_output).len());
 
-                tx.output.push(change_output);
-            }
-            None => {
-                // there's only one output, send everything to it
-                tx.output[0].value = change_val;
+        let drain_val = (coin_selection.selected_amount() - outgoing).saturating_sub(fee_amount);
 
-                // the single recipient is our address
-                if self.is_mine(&tx.output[0].script_pubkey)? {
-                    received = change_val;
+        if tx.output.is_empty() {
+            if params.drain_to.is_some() {
+                if drain_val.is_dust() {
+                    return Err(Error::InsufficientFunds {
+                        needed: DUST_LIMIT_SATOSHI,
+                        available: drain_val,
+                    });
                 }
+            } else {
+                return Err(Error::NoRecipients);
             }
         }
 
+        if drain_val.is_dust() {
+            fee_amount += drain_val;
+        } else {
+            drain_output.value = drain_val;
+            if self.is_mine(&drain_output.script_pubkey)? {
+                received += drain_val;
+            }
+            tx.output.push(drain_output);
+        }
+
         // sort input/outputs according to the chosen algorithm
         params.ordering.sort_tx(&mut tx);
 
@@ -710,6 +712,7 @@ where
             received,
             sent,
             fee: Some(fee_amount),
+            verified: true,
         };
 
         Ok((psbt, transaction_details))
@@ -721,10 +724,6 @@ where
     /// *repalce by fee* (RBF). If the transaction can be fee bumped then it returns a [`TxBuilder`]
     /// pre-populated with the inputs and outputs of the original transaction.
     ///
-    /// **NOTE**: if the original transaction was made with [`TxBuilder::set_single_recipient`],
-    /// the [`TxBuilder::maintain_single_recipient`] flag should be enabled to correctly reduce the
-    /// only output's value in order to increase the fees.
-    ///
     /// ## Example
     ///
     /// ```no_run
@@ -776,8 +775,10 @@ where
             return Err(Error::IrreplaceableTransaction);
         }
 
-        let vbytes = tx.get_weight() as f32 / 4.0;
-        let feerate = details.fee.ok_or(Error::FeeRateUnavailable)? as f32 / vbytes;
+        let feerate = FeeRate::from_wu(
+            details.fee.ok_or(Error::FeeRateUnavailable)?,
+            tx.get_weight(),
+        );
 
         // remove the inputs from the tx and process them
         let original_txin = tx.input.drain(..).collect::<Vec<_>>();
@@ -854,7 +855,7 @@ where
             utxos: original_utxos,
             bumping_fee: Some(tx_builder::PreviousFee {
                 absolute: details.fee.ok_or(Error::FeeRateUnavailable)?,
-                rate: feerate,
+                rate: feerate.as_sat_vb(),
             }),
             ..Default::default()
         };
@@ -1522,18 +1523,33 @@ where
         // TODO: what if i generate an address first and cache some addresses?
         // TODO: we should sync if generating an address triggers a new batch to be stored
         if run_setup {
-            maybe_await!(self.client.setup(
-                None,
-                self.database.borrow_mut().deref_mut(),
-                progress_update,
-            ))
+            maybe_await!(self
+                .client
+                .setup(self.database.borrow_mut().deref_mut(), progress_update,))?;
         } else {
-            maybe_await!(self.client.sync(
-                None,
-                self.database.borrow_mut().deref_mut(),
-                progress_update,
-            ))
+            maybe_await!(self
+                .client
+                .sync(self.database.borrow_mut().deref_mut(), progress_update,))?;
         }
+
+        #[cfg(feature = "verify")]
+        {
+            debug!("Verifying transactions...");
+            for mut tx in self.database.borrow().iter_txs(true)? {
+                if !tx.verified {
+                    verify::verify_tx(
+                        tx.transaction.as_ref().ok_or(Error::TransactionNotFound)?,
+                        self.database.borrow().deref(),
+                        &self.client,
+                    )?;
+
+                    tx.verified = true;
+                    self.database.borrow_mut().set_tx(&tx)?;
+                }
+            }
+        }
+
+        Ok(())
     }
 
     /// Return a reference to the internal blockchain client
@@ -1541,11 +1557,6 @@ where
         &self.client
     }
 
-    /// Get the Bitcoin network the wallet is using.
-    pub fn network(&self) -> Network {
-        self.network
-    }
-
     /// Broadcast a transaction to the network
     #[maybe_async]
     pub fn broadcast(&self, tx: Transaction) -> Result<Txid, Error> {
@@ -1555,19 +1566,60 @@ where
     }
 }
 
+/// Return a fake wallet that appears to be funded for testing.
+pub fn get_funded_wallet(
+    descriptor: &str,
+) -> (
+    Wallet<(), MemoryDatabase>,
+    (String, Option<String>),
+    bitcoin::Txid,
+) {
+    let descriptors = testutils!(@descriptors (descriptor));
+    let wallet = Wallet::new_offline(
+        &descriptors.0,
+        None,
+        Network::Regtest,
+        MemoryDatabase::new(),
+    )
+    .unwrap();
+
+    let funding_address_kix = 0;
+
+    let tx_meta = testutils! {
+            @tx ( (@external descriptors, funding_address_kix) => 50_000 ) (@confirmations 1)
+    };
+
+    wallet
+        .database
+        .borrow_mut()
+        .set_script_pubkey(
+            &bitcoin::Address::from_str(&tx_meta.output.get(0).unwrap().to_address)
+                .unwrap()
+                .script_pubkey(),
+            KeychainKind::External,
+            funding_address_kix,
+        )
+        .unwrap();
+    wallet
+        .database
+        .borrow_mut()
+        .set_last_index(KeychainKind::External, funding_address_kix)
+        .unwrap();
+
+    let txid = crate::populate_test_db!(wallet.database.borrow_mut(), tx_meta, Some(100));
+
+    (wallet, descriptors, txid)
+}
+
 #[cfg(test)]
 pub(crate) mod test {
-    use std::str::FromStr;
-
     use bitcoin::{util::psbt, Network};
 
-    use crate::database::memory::MemoryDatabase;
     use crate::database::Database;
     use crate::types::KeychainKind;
 
     use super::*;
     use crate::signer::{SignOptions, SignerError};
-    use crate::testutils;
     use crate::wallet::AddressIndex::{LastUnused, New, Peek, Reset};
 
     #[test]
@@ -1679,50 +1731,6 @@ pub(crate) mod test {
         "wsh(and_v(v:pk(cVpPVruEDdmutPzisEsYvtST1usBR3ntr8pXSyt6D2YYqXRyPcFW),after(100000)))"
     }
 
-    pub(crate) fn get_funded_wallet(
-        descriptor: &str,
-    ) -> (
-        Wallet<(), MemoryDatabase>,
-        (String, Option<String>),
-        bitcoin::Txid,
-    ) {
-        let descriptors = testutils!(@descriptors (descriptor));
-        let wallet = Wallet::new_offline(
-            &descriptors.0,
-            None,
-            Network::Regtest,
-            MemoryDatabase::new(),
-        )
-        .unwrap();
-
-        let funding_address_kix = 0;
-
-        let tx_meta = testutils! {
-                @tx ( (@external descriptors, funding_address_kix) => 50_000 ) (@confirmations 1)
-        };
-
-        wallet
-            .database
-            .borrow_mut()
-            .set_script_pubkey(
-                &bitcoin::Address::from_str(&tx_meta.output.get(0).unwrap().to_address)
-                    .unwrap()
-                    .script_pubkey(),
-                KeychainKind::External,
-                funding_address_kix,
-            )
-            .unwrap();
-        wallet
-            .database
-            .borrow_mut()
-            .set_last_index(KeychainKind::External, funding_address_kix)
-            .unwrap();
-
-        let txid = crate::populate_test_db!(wallet.database.borrow_mut(), tx_meta, Some(100));
-
-        (wallet, descriptors, txid)
-    }
-
     macro_rules! assert_fee_rate {
         ($tx:expr, $fees:expr, $fee_rate:expr $( ,@dust_change $( $dust_change:expr )* )* $( ,@add_signature $( $add_signature:expr )* )* ) => ({
             let mut tx = $tx.clone();
@@ -1741,13 +1749,13 @@ pub(crate) mod test {
                 dust_change = true;
             )*
 
-            let tx_fee_rate = $fees as f32 / (tx.get_weight() as f32 / 4.0);
-            let fee_rate = $fee_rate.as_sat_vb();
+            let tx_fee_rate = FeeRate::from_wu($fees, tx.get_weight());
+            let fee_rate = $fee_rate;
 
             if !dust_change {
-                assert!((tx_fee_rate - fee_rate).abs() < 0.5, "Expected fee rate of {}, the tx has {}", fee_rate, tx_fee_rate);
+                assert!((tx_fee_rate - fee_rate).as_sat_vb().abs() < 0.5, "Expected fee rate of {:?}, the tx has {:?}", fee_rate, tx_fee_rate);
             } else {
-                assert!(tx_fee_rate >= fee_rate, "Expected fee rate of at least {}, the tx has {}", fee_rate, tx_fee_rate);
+                assert!(tx_fee_rate >= fee_rate, "Expected fee rate of at least {:?}, the tx has {:?}", fee_rate, tx_fee_rate);
             }
         });
     }
@@ -1973,13 +1981,11 @@ pub(crate) mod test {
     }
 
     #[test]
-    fn test_create_tx_single_recipient_drain_wallet() {
+    fn test_create_tx_drain_wallet_and_drain_to() {
         let (wallet, _, _) = get_funded_wallet(get_test_wpkh());
         let addr = wallet.get_address(New).unwrap();
         let mut builder = wallet.build_tx();
-        builder
-            .set_single_recipient(addr.script_pubkey())
-            .drain_wallet();
+        builder.drain_to(addr.script_pubkey()).drain_wallet();
         let (psbt, details) = builder.finish().unwrap();
 
         assert_eq!(psbt.global.unsigned_tx.output.len(), 1);
@@ -1989,6 +1995,33 @@ pub(crate) mod test {
         );
     }
 
+    #[test]
+    fn test_create_tx_drain_wallet_and_drain_to_and_with_recipient() {
+        let (wallet, _, _) = get_funded_wallet(get_test_wpkh());
+        let addr = Address::from_str("2N4eQYCbKUHCCTUjBJeHcJp9ok6J2GZsTDt").unwrap();
+        let drain_addr = wallet.get_address(New).unwrap();
+        let mut builder = wallet.build_tx();
+        builder
+            .add_recipient(addr.script_pubkey(), 20_000)
+            .drain_to(drain_addr.script_pubkey())
+            .drain_wallet();
+        let (psbt, details) = builder.finish().unwrap();
+        dbg!(&psbt);
+        let outputs = psbt.global.unsigned_tx.output;
+
+        assert_eq!(outputs.len(), 2);
+        let main_output = outputs
+            .iter()
+            .find(|x| x.script_pubkey == addr.script_pubkey())
+            .unwrap();
+        let drain_output = outputs
+            .iter()
+            .find(|x| x.script_pubkey == drain_addr.script_pubkey())
+            .unwrap();
+        assert_eq!(main_output.value, 20_000,);
+        assert_eq!(drain_output.value, 30_000 - details.fee.unwrap_or(0));
+    }
+
     #[test]
     fn test_create_tx_default_fee_rate() {
         let (wallet, _, _) = get_funded_wallet(get_test_wpkh());
@@ -2019,7 +2052,7 @@ pub(crate) mod test {
         let addr = wallet.get_address(New).unwrap();
         let mut builder = wallet.build_tx();
         builder
-            .set_single_recipient(addr.script_pubkey())
+            .drain_to(addr.script_pubkey())
             .drain_wallet()
             .fee_absolute(100);
         let (psbt, details) = builder.finish().unwrap();
@@ -2038,7 +2071,7 @@ pub(crate) mod test {
         let addr = wallet.get_address(New).unwrap();
         let mut builder = wallet.build_tx();
         builder
-            .set_single_recipient(addr.script_pubkey())
+            .drain_to(addr.script_pubkey())
             .drain_wallet()
             .fee_absolute(0);
         let (psbt, details) = builder.finish().unwrap();
@@ -2058,7 +2091,7 @@ pub(crate) mod test {
         let addr = wallet.get_address(New).unwrap();
         let mut builder = wallet.build_tx();
         builder
-            .set_single_recipient(addr.script_pubkey())
+            .drain_to(addr.script_pubkey())
             .drain_wallet()
             .fee_absolute(60_000);
         let (_psbt, _details) = builder.finish().unwrap();
@@ -2099,13 +2132,13 @@ pub(crate) mod test {
 
     #[test]
     #[should_panic(expected = "InsufficientFunds")]
-    fn test_create_tx_single_recipient_dust_amount() {
+    fn test_create_tx_drain_to_dust_amount() {
         let (wallet, _, _) = get_funded_wallet(get_test_wpkh());
         let addr = wallet.get_address(New).unwrap();
         // very high fee rate, so that the only output would be below dust
         let mut builder = wallet.build_tx();
         builder
-            .set_single_recipient(addr.script_pubkey())
+            .drain_to(addr.script_pubkey())
             .drain_wallet()
             .fee_rate(FeeRate::from_sat_per_vb(453.0));
         builder.finish().unwrap();
@@ -2166,9 +2199,7 @@ pub(crate) mod test {
         let (wallet, _, _) = get_funded_wallet("wpkh([d34db33f/44'/0'/0']tpubDEnoLuPdBep9bzw5LoGYpsxUQYheRQ9gcgrJhJEcdKFB9cWQRyYmkCyRoTqeD4tJYiVVgt6A3rN6rWn9RYhR9sBsGxji29LYWHuKKbdb1ev/0/*)");
         let addr = wallet.get_address(New).unwrap();
         let mut builder = wallet.build_tx();
-        builder
-            .set_single_recipient(addr.script_pubkey())
-            .drain_wallet();
+        builder.drain_to(addr.script_pubkey()).drain_wallet();
         let (psbt, _) = builder.finish().unwrap();
 
         assert_eq!(psbt.inputs[0].bip32_derivation.len(), 1);
@@ -2192,9 +2223,7 @@ pub(crate) mod test {
 
         let addr = testutils!(@external descriptors, 5);
         let mut builder = wallet.build_tx();
-        builder
-            .set_single_recipient(addr.script_pubkey())
-            .drain_wallet();
+        builder.drain_to(addr.script_pubkey()).drain_wallet();
         let (psbt, _) = builder.finish().unwrap();
 
         assert_eq!(psbt.outputs[0].bip32_derivation.len(), 1);
@@ -2215,9 +2244,7 @@ pub(crate) mod test {
             get_funded_wallet("sh(pk(cVpPVruEDdmutPzisEsYvtST1usBR3ntr8pXSyt6D2YYqXRyPcFW))");
         let addr = wallet.get_address(New).unwrap();
         let mut builder = wallet.build_tx();
-        builder
-            .set_single_recipient(addr.script_pubkey())
-            .drain_wallet();
+        builder.drain_to(addr.script_pubkey()).drain_wallet();
         let (psbt, _) = builder.finish().unwrap();
 
         assert_eq!(
@@ -2240,9 +2267,7 @@ pub(crate) mod test {
             get_funded_wallet("wsh(pk(cVpPVruEDdmutPzisEsYvtST1usBR3ntr8pXSyt6D2YYqXRyPcFW))");
         let addr = wallet.get_address(New).unwrap();
         let mut builder = wallet.build_tx();
-        builder
-            .set_single_recipient(addr.script_pubkey())
-            .drain_wallet();
+        builder.drain_to(addr.script_pubkey()).drain_wallet();
         let (psbt, _) = builder.finish().unwrap();
 
         assert_eq!(psbt.inputs[0].redeem_script, None);
@@ -2265,9 +2290,7 @@ pub(crate) mod test {
             get_funded_wallet("sh(wsh(pk(cVpPVruEDdmutPzisEsYvtST1usBR3ntr8pXSyt6D2YYqXRyPcFW)))");
         let addr = wallet.get_address(New).unwrap();
         let mut builder = wallet.build_tx();
-        builder
-            .set_single_recipient(addr.script_pubkey())
-            .drain_wallet();
+        builder.drain_to(addr.script_pubkey()).drain_wallet();
         let (psbt, _) = builder.finish().unwrap();
 
         let script = Script::from(
@@ -2287,9 +2310,7 @@ pub(crate) mod test {
             get_funded_wallet("sh(pk(cVpPVruEDdmutPzisEsYvtST1usBR3ntr8pXSyt6D2YYqXRyPcFW))");
         let addr = wallet.get_address(New).unwrap();
         let mut builder = wallet.build_tx();
-        builder
-            .set_single_recipient(addr.script_pubkey())
-            .drain_wallet();
+        builder.drain_to(addr.script_pubkey()).drain_wallet();
         let (psbt, _) = builder.finish().unwrap();
 
         assert!(psbt.inputs[0].non_witness_utxo.is_some());
@@ -2303,7 +2324,7 @@ pub(crate) mod test {
         let addr = wallet.get_address(New).unwrap();
         let mut builder = wallet.build_tx();
         builder
-            .set_single_recipient(addr.script_pubkey())
+            .drain_to(addr.script_pubkey())
             .only_witness_utxo()
             .drain_wallet();
         let (psbt, _) = builder.finish().unwrap();
@@ -2318,9 +2339,7 @@ pub(crate) mod test {
             get_funded_wallet("sh(wpkh(cVpPVruEDdmutPzisEsYvtST1usBR3ntr8pXSyt6D2YYqXRyPcFW))");
         let addr = wallet.get_address(New).unwrap();
         let mut builder = wallet.build_tx();
-        builder
-            .set_single_recipient(addr.script_pubkey())
-            .drain_wallet();
+        builder.drain_to(addr.script_pubkey()).drain_wallet();
         let (psbt, _) = builder.finish().unwrap();
 
         assert!(psbt.inputs[0].witness_utxo.is_some());
@@ -2332,9 +2351,7 @@ pub(crate) mod test {
             get_funded_wallet("wsh(pk(cVpPVruEDdmutPzisEsYvtST1usBR3ntr8pXSyt6D2YYqXRyPcFW))");
         let addr = wallet.get_address(New).unwrap();
         let mut builder = wallet.build_tx();
-        builder
-            .set_single_recipient(addr.script_pubkey())
-            .drain_wallet();
+        builder.drain_to(addr.script_pubkey()).drain_wallet();
         let (psbt, _) = builder.finish().unwrap();
 
         assert!(psbt.inputs[0].non_witness_utxo.is_some());
@@ -2968,7 +2985,7 @@ pub(crate) mod test {
         let addr = Address::from_str("2N1Ffz3WaNzbeLFBb51xyFMHYSEUXcbiSoX").unwrap();
         let mut builder = wallet.build_tx();
         builder
-            .set_single_recipient(addr.script_pubkey())
+            .drain_to(addr.script_pubkey())
             .drain_wallet()
             .enable_rbf();
         let (psbt, mut original_details) = builder.finish().unwrap();
@@ -2992,7 +3009,7 @@ pub(crate) mod test {
         let mut builder = wallet.build_fee_bump(txid).unwrap();
         builder
             .fee_rate(FeeRate::from_sat_per_vb(2.5))
-            .maintain_single_recipient()
+            .allow_shrinking(addr.script_pubkey())
             .unwrap();
         let (psbt, details) = builder.finish().unwrap();
 
@@ -3012,7 +3029,7 @@ pub(crate) mod test {
         let addr = Address::from_str("2N1Ffz3WaNzbeLFBb51xyFMHYSEUXcbiSoX").unwrap();
         let mut builder = wallet.build_tx();
         builder
-            .set_single_recipient(addr.script_pubkey())
+            .drain_to(addr.script_pubkey())
             .drain_wallet()
             .enable_rbf();
         let (psbt, mut original_details) = builder.finish().unwrap();
@@ -3035,7 +3052,7 @@ pub(crate) mod test {
 
         let mut builder = wallet.build_fee_bump(txid).unwrap();
         builder
-            .maintain_single_recipient()
+            .allow_shrinking(addr.script_pubkey())
             .unwrap()
             .fee_absolute(300);
         let (psbt, details) = builder.finish().unwrap();
@@ -3066,7 +3083,7 @@ pub(crate) mod test {
         let addr = Address::from_str("2N1Ffz3WaNzbeLFBb51xyFMHYSEUXcbiSoX").unwrap();
         let mut builder = wallet.build_tx();
         builder
-            .set_single_recipient(addr.script_pubkey())
+            .drain_to(addr.script_pubkey())
             .add_utxo(outpoint)
             .unwrap()
             .manually_selected_only()
@@ -3095,7 +3112,7 @@ pub(crate) mod test {
         let mut builder = wallet.build_fee_bump(txid).unwrap();
         builder
             .drain_wallet()
-            .maintain_single_recipient()
+            .allow_shrinking(addr.script_pubkey())
             .unwrap()
             .fee_rate(FeeRate::from_sat_per_vb(5.0));
         let (_, details) = builder.finish().unwrap();
@@ -3110,7 +3127,7 @@ pub(crate) mod test {
         // them, and make sure that `bump_fee` doesn't try to add more. This fails because we've
         // told the wallet it's not allowed to add more inputs AND it can't reduce the value of the
         // existing output. In other words, bump_fee + manually_selected_only is always an error
-        // unless you've also set "maintain_single_recipient".
+        // unless you've also set "allow_shrinking" OR there is a change output.
         let incoming_txid = crate::populate_test_db!(
             wallet.database.borrow_mut(),
             testutils! (@tx ( (@external descriptors, 0) => 25_000 ) (@confirmations 1)),
@@ -3123,7 +3140,7 @@ pub(crate) mod test {
         let addr = Address::from_str("2N1Ffz3WaNzbeLFBb51xyFMHYSEUXcbiSoX").unwrap();
         let mut builder = wallet.build_tx();
         builder
-            .set_single_recipient(addr.script_pubkey())
+            .drain_to(addr.script_pubkey())
             .add_utxo(outpoint)
             .unwrap()
             .manually_selected_only()
@@ -3289,11 +3306,11 @@ pub(crate) mod test {
             Some(100),
         );
 
-        // initially make a tx without change by using `set_single_recipient`
+        // initially make a tx without change by using `drain_to`
         let addr = Address::from_str("2N1Ffz3WaNzbeLFBb51xyFMHYSEUXcbiSoX").unwrap();
         let mut builder = wallet.build_tx();
         builder
-            .set_single_recipient(addr.script_pubkey())
+            .drain_to(addr.script_pubkey())
             .add_utxo(OutPoint {
                 txid: incoming_txid,
                 vout: 0,
@@ -3321,7 +3338,7 @@ pub(crate) mod test {
             .set_tx(&original_details)
             .unwrap();
 
-        // now bump the fees without using `maintain_single_recipient`. the wallet should add an
+        // now bump the fees without using `allow_shrinking`. the wallet should add an
         // extra input and a change output, and leave the original output untouched
         let mut builder = wallet.build_fee_bump(txid).unwrap();
         builder.fee_rate(FeeRate::from_sat_per_vb(50.0));
@@ -3567,9 +3584,7 @@ pub(crate) mod test {
         let (wallet, _, _) = get_funded_wallet("wpkh(tprv8ZgxMBicQKsPd3EupYiPRhaMooHKUHJxNsTfYuScep13go8QFfHdtkG9nRkFGb7busX4isf6X9dURGCoKgitaApQ6MupRhZMcELAxTBRJgS/*)");
         let addr = wallet.get_address(New).unwrap();
         let mut builder = wallet.build_tx();
-        builder
-            .set_single_recipient(addr.script_pubkey())
-            .drain_wallet();
+        builder.drain_to(addr.script_pubkey()).drain_wallet();
         let (mut psbt, _) = builder.finish().unwrap();
 
         let finalized = wallet.sign(&mut psbt, Default::default()).unwrap();
@@ -3584,9 +3599,7 @@ pub(crate) mod test {
         let (wallet, _, _) = get_funded_wallet("wpkh([d34db33f/84h/1h/0h]tprv8ZgxMBicQKsPd3EupYiPRhaMooHKUHJxNsTfYuScep13go8QFfHdtkG9nRkFGb7busX4isf6X9dURGCoKgitaApQ6MupRhZMcELAxTBRJgS/*)");
         let addr = wallet.get_address(New).unwrap();
         let mut builder = wallet.build_tx();
-        builder
-            .set_single_recipient(addr.script_pubkey())
-            .drain_wallet();
+        builder.drain_to(addr.script_pubkey()).drain_wallet();
         let (mut psbt, _) = builder.finish().unwrap();
 
         let finalized = wallet.sign(&mut psbt, Default::default()).unwrap();
@@ -3601,9 +3614,7 @@ pub(crate) mod test {
         let (wallet, _, _) = get_funded_wallet("wpkh(tprv8ZgxMBicQKsPd3EupYiPRhaMooHKUHJxNsTfYuScep13go8QFfHdtkG9nRkFGb7busX4isf6X9dURGCoKgitaApQ6MupRhZMcELAxTBRJgS/44'/0'/0'/0/*)");
         let addr = wallet.get_address(New).unwrap();
         let mut builder = wallet.build_tx();
-        builder
-            .set_single_recipient(addr.script_pubkey())
-            .drain_wallet();
+        builder.drain_to(addr.script_pubkey()).drain_wallet();
         let (mut psbt, _) = builder.finish().unwrap();
 
         let finalized = wallet.sign(&mut psbt, Default::default()).unwrap();
@@ -3618,9 +3629,7 @@ pub(crate) mod test {
         let (wallet, _, _) = get_funded_wallet("sh(wpkh(tprv8ZgxMBicQKsPd3EupYiPRhaMooHKUHJxNsTfYuScep13go8QFfHdtkG9nRkFGb7busX4isf6X9dURGCoKgitaApQ6MupRhZMcELAxTBRJgS/*))");
         let addr = wallet.get_address(New).unwrap();
         let mut builder = wallet.build_tx();
-        builder
-            .set_single_recipient(addr.script_pubkey())
-            .drain_wallet();
+        builder.drain_to(addr.script_pubkey()).drain_wallet();
         let (mut psbt, _) = builder.finish().unwrap();
 
         let finalized = wallet.sign(&mut psbt, Default::default()).unwrap();
@@ -3636,9 +3645,7 @@ pub(crate) mod test {
             get_funded_wallet("wpkh(cVpPVruEDdmutPzisEsYvtST1usBR3ntr8pXSyt6D2YYqXRyPcFW)");
         let addr = wallet.get_address(New).unwrap();
         let mut builder = wallet.build_tx();
-        builder
-            .set_single_recipient(addr.script_pubkey())
-            .drain_wallet();
+        builder.drain_to(addr.script_pubkey()).drain_wallet();
         let (mut psbt, _) = builder.finish().unwrap();
 
         let finalized = wallet.sign(&mut psbt, Default::default()).unwrap();
@@ -3653,9 +3660,7 @@ pub(crate) mod test {
         let (wallet, _, _) = get_funded_wallet("wpkh(tprv8ZgxMBicQKsPd3EupYiPRhaMooHKUHJxNsTfYuScep13go8QFfHdtkG9nRkFGb7busX4isf6X9dURGCoKgitaApQ6MupRhZMcELAxTBRJgS/*)");
         let addr = wallet.get_address(New).unwrap();
         let mut builder = wallet.build_tx();
-        builder
-            .set_single_recipient(addr.script_pubkey())
-            .drain_wallet();
+        builder.drain_to(addr.script_pubkey()).drain_wallet();
         let (mut psbt, _) = builder.finish().unwrap();
 
         psbt.inputs[0].bip32_derivation.clear();
@@ -3737,7 +3742,7 @@ pub(crate) mod test {
         let addr = wallet.get_address(New).unwrap();
         let mut builder = wallet.build_tx();
         builder
-            .set_single_recipient(addr.script_pubkey())
+            .drain_to(addr.script_pubkey())
             .sighash(sighash)
             .drain_wallet();
         let (mut psbt, _) = builder.finish().unwrap();

src/wallet/tx_builder.rs

@@ -133,7 +133,7 @@ pub struct TxBuilder<'a, B, D, Cs, Ctx> {
 pub(crate) struct TxParams {
     pub(crate) recipients: Vec<(Script, u64)>,
     pub(crate) drain_wallet: bool,
-    pub(crate) single_recipient: Option<Script>,
+    pub(crate) drain_to: Option<Script>,
     pub(crate) fee_policy: Option<FeePolicy>,
     pub(crate) internal_policy_path: Option<BTreeMap<String, Vec<usize>>>,
     pub(crate) external_policy_path: Option<BTreeMap<String, Vec<usize>>>,
@@ -560,49 +560,81 @@ impl<'a, B, D: BatchDatabase, Cs: CoinSelectionAlgorithm<D>> TxBuilder<'a, B, D,
         self
     }
 
-    /// Set a single recipient that will get all the selected funds minus the fee. No change will
-    /// be created
+    /// Sets the address to *drain* excess coins to.
     ///
-    /// This method overrides any recipient set with [`set_recipients`](Self::set_recipients) or
-    /// [`add_recipient`](Self::add_recipient).
+    /// Usually, when there are excess coins they are sent to a change address generated by the
+    /// wallet. This option replaces the usual change address with an arbitrary `script_pubkey` of
+    /// your choosing. Just as with a change output, if the drain output is not needed (the excess
+    /// coins are too small) it will not be included in the resulting transaction. The only
+    /// difference is that it is valid to use `drain_to` without setting any ordinary recipients
+    /// with [`add_recipient`] (but it is perfectly fine to add recipients as well).
     ///
-    /// It can only be used in conjunction with [`drain_wallet`](Self::drain_wallet) to send the
-    /// entire content of the wallet (minus filters) to a single recipient or with a
-    /// list of manually selected UTXOs by enabling [`manually_selected_only`](Self::manually_selected_only)
-    /// and selecting them with or [`add_utxo`](Self::add_utxo).
+    /// When bumping the fees of a transaction made with this option, you probably want to
+    /// use [`allow_shrinking`] to allow this output to be reduced to pay for the extra fees.
     ///
-    /// When bumping the fees of a transaction made with this option, the user should remeber to
-    /// add [`maintain_single_recipient`](Self::maintain_single_recipient) to correctly update the
-    /// single output instead of adding one more for the change.
-    pub fn set_single_recipient(&mut self, recipient: Script) -> &mut Self {
-        self.params.single_recipient = Some(recipient);
-        self.params.recipients.clear();
-
+    /// # Example
+    ///
+    /// `drain_to` is very useful for draining all the coins in a wallet with [`drain_wallet`] to a
+    /// single address.
+    ///
+    /// ```
+    /// # use std::str::FromStr;
+    /// # use bitcoin::*;
+    /// # use bdk::*;
+    /// # use bdk::wallet::tx_builder::CreateTx;
+    /// # let to_address = Address::from_str("2N4eQYCbKUHCCTUjBJeHcJp9ok6J2GZsTDt").unwrap();
+    /// # let wallet = doctest_wallet!();
+    /// let mut tx_builder = wallet.build_tx();
+    ///
+    /// tx_builder
+    ///     // Spend all outputs in this wallet.
+    ///     .drain_wallet()
+    ///     // Send the excess (which is all the coins minus the fee) to this address.
+    ///     .drain_to(to_address.script_pubkey())
+    ///     .fee_rate(FeeRate::from_sat_per_vb(5.0))
+    ///     .enable_rbf();
+    /// let (psbt, tx_details) = tx_builder.finish()?;
+    /// # Ok::<(), bdk::Error>(())
+    /// ```
+    ///
+    /// [`allow_shrinking`]: Self::allow_shrinking
+    /// [`add_recipient`]: Self::add_recipient
+    /// [`drain_wallet`]: Self::drain_wallet
+    pub fn drain_to(&mut self, script_pubkey: Script) -> &mut Self {
+        self.params.drain_to = Some(script_pubkey);
         self
     }
 }
 
 // methods supported only by bump_fee
 impl<'a, B, D: BatchDatabase> TxBuilder<'a, B, D, DefaultCoinSelectionAlgorithm, BumpFee> {
-    /// Bump the fees of a transaction made with [`set_single_recipient`](Self::set_single_recipient)
+    /// Explicitly tells the wallet that it is allowed to reduce the fee of the output matching this
+    /// `script_pubkey` in order to bump the transaction fee. Without specifying this the wallet
+    /// will attempt to find a change output to shrink instead.
     ///
-    /// Unless extra inputs are specified with [`add_utxo`], this flag will make
-    /// `bump_fee` reduce the value of the existing output, or fail if it would be consumed
-    /// entirely given the higher new fee rate.
+    /// **Note** that the output may shrink to below the dust limit and therefore be removed. If it is
+    /// preserved then it is currently not guaranteed to be in the same position as it was
+    /// originally.
     ///
-    /// If extra inputs are added and they are not entirely consumed in fees, a change output will not
-    /// be added; the existing output will simply grow in value.
-    ///
-    /// Fails if the transaction has more than one outputs.
-    ///
-    /// [`add_utxo`]: Self::add_utxo
-    pub fn maintain_single_recipient(&mut self) -> Result<&mut Self, Error> {
-        let mut recipients = self.params.recipients.drain(..).collect::<Vec<_>>();
-        if recipients.len() != 1 {
-            return Err(Error::SingleRecipientMultipleOutputs);
+    /// Returns an `Err` if `script_pubkey` can't be found among the recipients of the
+    /// transaction we are bumping.
+    pub fn allow_shrinking(&mut self, script_pubkey: Script) -> Result<&mut Self, Error> {
+        match self
+            .params
+            .recipients
+            .iter()
+            .position(|(recipient_script, _)| *recipient_script == script_pubkey)
+        {
+            Some(position) => {
+                self.params.recipients.remove(position);
+                self.params.drain_to = Some(script_pubkey);
+                Ok(self)
+            }
+            None => Err(Error::Generic(format!(
+                "{} was not in the original transaction",
+                script_pubkey
+            ))),
         }
-        self.params.single_recipient = Some(recipients.pop().unwrap().0);
-        Ok(self)
     }
 }
 

src/wallet/verify.rs

@@ -0,0 +1,185 @@
+// Bitcoin Dev Kit
+// Written in 2021 by Alekos Filini <alekos.filini@gmail.com>
+//
+// Copyright (c) 2020-2021 Bitcoin Dev Kit Developers
+//
+// This file is licensed under the Apache License, Version 2.0 <LICENSE-APACHE
+// or http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your option.
+// You may not use this file except in accordance with one or both of these
+// licenses.
+
+//! Verify transactions against the consensus rules
+
+use std::collections::HashMap;
+use std::fmt;
+
+use bitcoin::consensus::serialize;
+use bitcoin::{OutPoint, Transaction, Txid};
+
+use crate::blockchain::Blockchain;
+use crate::database::Database;
+use crate::error::Error;
+
+/// Verify a transaction against the consensus rules
+///
+/// This function uses [`bitcoinconsensus`] to verify transactions by fetching the required data
+/// either from the [`Database`] or using the [`Blockchain`].
+///
+/// Depending on the [capabilities](crate::blockchain::Blockchain::get_capabilities) of the
+/// [`Blockchain`] backend, the method could fail when called with old "historical" transactions or
+/// with unconfirmed transactions that have been evicted from the backend's memory.
+pub fn verify_tx<D: Database, B: Blockchain>(
+    tx: &Transaction,
+    database: &D,
+    blockchain: &B,
+) -> Result<(), VerifyError> {
+    log::debug!("Verifying {}", tx.txid());
+
+    let serialized_tx = serialize(tx);
+    let mut tx_cache = HashMap::<_, Transaction>::new();
+
+    for (index, input) in tx.input.iter().enumerate() {
+        let prev_tx = if let Some(prev_tx) = tx_cache.get(&input.previous_output.txid) {
+            prev_tx.clone()
+        } else if let Some(prev_tx) = database.get_raw_tx(&input.previous_output.txid)? {
+            prev_tx
+        } else if let Some(prev_tx) = blockchain.get_tx(&input.previous_output.txid)? {
+            prev_tx
+        } else {
+            return Err(VerifyError::MissingInputTx(input.previous_output.txid));
+        };
+
+        let spent_output = prev_tx
+            .output
+            .get(input.previous_output.vout as usize)
+            .ok_or(VerifyError::InvalidInput(input.previous_output))?;
+
+        bitcoinconsensus::verify(
+            &spent_output.script_pubkey.to_bytes(),
+            spent_output.value,
+            &serialized_tx,
+            index,
+        )?;
+
+        // Since we have a local cache we might as well cache stuff from the db, as it will very
+        // likely decrease latency compared to reading from disk or performing an SQL query.
+        tx_cache.insert(prev_tx.txid(), prev_tx);
+    }
+
+    Ok(())
+}
+
+/// Error during validation of a tx agains the consensus rules
+#[derive(Debug)]
+pub enum VerifyError {
+    /// The transaction being spent is not available in the database or the blockchain client
+    MissingInputTx(Txid),
+    /// The transaction being spent doesn't have the requested output
+    InvalidInput(OutPoint),
+
+    /// Consensus error
+    Consensus(bitcoinconsensus::Error),
+
+    /// Generic error
+    ///
+    /// It has to be wrapped in a `Box` since `Error` has a variant that contains this enum
+    Global(Box<Error>),
+}
+
+impl fmt::Display for VerifyError {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        write!(f, "{:?}", self)
+    }
+}
+
+impl std::error::Error for VerifyError {}
+
+impl From<Error> for VerifyError {
+    fn from(other: Error) -> Self {
+        VerifyError::Global(Box::new(other))
+    }
+}
+impl_error!(bitcoinconsensus::Error, Consensus, VerifyError);
+
+#[cfg(test)]
+mod test {
+    use std::collections::HashSet;
+
+    use bitcoin::consensus::encode::deserialize;
+    use bitcoin::hashes::hex::FromHex;
+    use bitcoin::{Transaction, Txid};
+
+    use crate::blockchain::{Blockchain, Capability, Progress};
+    use crate::database::{BatchDatabase, BatchOperations, MemoryDatabase};
+    use crate::FeeRate;
+
+    use super::*;
+
+    struct DummyBlockchain;
+
+    impl Blockchain for DummyBlockchain {
+        fn get_capabilities(&self) -> HashSet<Capability> {
+            Default::default()
+        }
+        fn setup<D: BatchDatabase, P: 'static + Progress>(
+            &self,
+            _database: &mut D,
+            _progress_update: P,
+        ) -> Result<(), Error> {
+            Ok(())
+        }
+        fn get_tx(&self, _txid: &Txid) -> Result<Option<Transaction>, Error> {
+            Ok(None)
+        }
+        fn broadcast(&self, _tx: &Transaction) -> Result<(), Error> {
+            Ok(())
+        }
+        fn get_height(&self) -> Result<u32, Error> {
+            Ok(42)
+        }
+        fn estimate_fee(&self, _target: usize) -> Result<FeeRate, Error> {
+            Ok(FeeRate::default_min_relay_fee())
+        }
+    }
+
+    #[test]
+    fn test_verify_fail_unsigned_tx() {
+        // https://blockstream.info/tx/95da344585fcf2e5f7d6cbf2c3df2dcce84f9196f7a7bb901a43275cd6eb7c3f
+        let prev_tx: Transaction = deserialize(&Vec::<u8>::from_hex("020000000101192dea5e66d444380e106f8e53acb171703f00d43fb6b3ae88ca5644bdb7e1000000006b48304502210098328d026ce138411f957966c1cf7f7597ccbb170f5d5655ee3e9f47b18f6999022017c3526fc9147830e1340e04934476a3d1521af5b4de4e98baf49ec4c072079e01210276f847f77ec8dd66d78affd3c318a0ed26d89dab33fa143333c207402fcec352feffffff023d0ac203000000001976a9144bfbaf6afb76cc5771bc6404810d1cc041a6933988aca4b956050000000017a91494d5543c74a3ee98e0cf8e8caef5dc813a0f34b48768cb0700").unwrap()).unwrap();
+        // https://blockstream.info/tx/aca326a724eda9a461c10a876534ecd5ae7b27f10f26c3862fb996f80ea2d45d
+        let signed_tx: Transaction = deserialize(&Vec::<u8>::from_hex("02000000013f7cebd65c27431a90bba7f796914fe8cc2ddfc3f2cbd6f7e5f2fc854534da95000000006b483045022100de1ac3bcdfb0332207c4a91f3832bd2c2915840165f876ab47c5f8996b971c3602201c6c053d750fadde599e6f5c4e1963df0f01fc0d97815e8157e3d59fe09ca30d012103699b464d1d8bc9e47d4fb1cdaa89a1c5783d68363c4dbc4b524ed3d857148617feffffff02836d3c01000000001976a914fc25d6d5c94003bf5b0c7b640a248e2c637fcfb088ac7ada8202000000001976a914fbed3d9b11183209a57999d54d59f67c019e756c88ac6acb0700").unwrap()).unwrap();
+
+        let mut database = MemoryDatabase::new();
+        let blockchain = DummyBlockchain;
+
+        let mut unsigned_tx = signed_tx.clone();
+        for input in &mut unsigned_tx.input {
+            input.script_sig = Default::default();
+            input.witness = Default::default();
+        }
+
+        let result = verify_tx(&signed_tx, &database, &blockchain);
+        assert!(result.is_err(), "Should fail with missing input tx");
+        assert!(
+            matches!(result, Err(VerifyError::MissingInputTx(txid)) if txid == prev_tx.txid()),
+            "Error should be a `MissingInputTx` error"
+        );
+
+        // insert the prev_tx
+        database.set_raw_tx(&prev_tx).unwrap();
+
+        let result = verify_tx(&unsigned_tx, &database, &blockchain);
+        assert!(result.is_err(), "Should fail since the TX is unsigned");
+        assert!(
+            matches!(result, Err(VerifyError::Consensus(_))),
+            "Error should be a `Consensus` error"
+        );
+
+        let result = verify_tx(&signed_tx, &database, &blockchain);
+        assert!(
+            result.is_ok(),
+            "Should work since the TX is correctly signed"
+        );
+    }
+}