Batch outspends requests

fixes #1902

backend/src/api/bitcoin/bitcoin-api-abstract-factory.ts

@@ -13,6 +13,7 @@ export interface AbstractBitcoinApi {
   $getAddressPrefix(prefix: string): string[];
   $sendRawTransaction(rawTransaction: string): Promise<string>;
   $getOutspends(txId: string): Promise<IEsploraApi.Outspend[]>;
+  $getBatchedOutspends(txId: string[]): Promise<IEsploraApi.Outspend[][]>;
 }
 export interface BitcoinRpcCredentials {
   host: string;

backend/src/api/bitcoin/bitcoin-api.ts

@@ -141,6 +141,15 @@ class BitcoinApi implements AbstractBitcoinApi {
     return outSpends;
   }
 
+  async $getBatchedOutspends(txId: string[]): Promise<IEsploraApi.Outspend[][]> {
+    const outspends: IEsploraApi.Outspend[][] = [];
+    for (const tx of txId) {
+      const outspend = await this.$getOutspends(tx);
+      outspends.push(outspend);
+    }
+    return outspends;
+  }
+
   $getEstimatedHashrate(blockHeight: number): Promise<number> {
     // 120 is the default block span in Core
     return this.bitcoindClient.getNetworkHashPs(120, blockHeight);

backend/src/api/bitcoin/esplora-api.ts

@@ -61,8 +61,18 @@ class ElectrsApi implements AbstractBitcoinApi {
     throw new Error('Method not implemented.');
   }
 
-  $getOutspends(): Promise<IEsploraApi.Outspend[]> {
-    throw new Error('Method not implemented.');
+  $getOutspends(txId: string): Promise<IEsploraApi.Outspend[]> {
+    return axios.get<IEsploraApi.Outspend[]>(config.ESPLORA.REST_API_URL + '/tx/' + txId, this.axiosConfig)
+      .then((response) => response.data);
+  }
+
+  async $getBatchedOutspends(txId: string[]): Promise<IEsploraApi.Outspend[][]> {
+    const outspends: IEsploraApi.Outspend[][] = [];
+    for (const tx of txId) {
+      const outspend = await this.$getOutspends(tx);
+      outspends.push(outspend);
+    }
+    return outspends;
   }
 }
 

backend/src/index.ts

@@ -195,6 +195,7 @@ class Server {
   setUpHttpApiRoutes() {
     this.app
       .get(config.MEMPOOL.API_URL_PREFIX + 'transaction-times', routes.getTransactionTimes)
+      .get(config.MEMPOOL.API_URL_PREFIX + 'outspends', routes.$getBatchedOutspends)
       .get(config.MEMPOOL.API_URL_PREFIX + 'cpfp/:txId', routes.getCpfpInfo)
       .get(config.MEMPOOL.API_URL_PREFIX + 'difficulty-adjustment', routes.getDifficultyChange)
       .get(config.MEMPOOL.API_URL_PREFIX + 'fees/recommended', routes.getRecommendedFees)

backend/src/routes.ts

@@ -120,6 +120,30 @@ class Routes {
     res.json(times);
   }
 
+  public async $getBatchedOutspends(req: Request, res: Response) {
+    if (!Array.isArray(req.query.txId)) {
+      res.status(500).send('Not an array');
+      return;
+    }
+    if (req.query.txId.length > 50) {
+      res.status(400).send('Too many txids requested');
+      return;
+    }
+    const txIds: string[] = [];
+    for (const _txId in req.query.txId) {
+      if (typeof req.query.txId[_txId] === 'string') {
+        txIds.push(req.query.txId[_txId].toString());
+      }
+    }
+
+    try {
+      const batchedOutspends = await bitcoinApi.$getBatchedOutspends(txIds);
+      res.json(batchedOutspends);
+    } catch (e) {
+      res.status(500).send(e instanceof Error ? e.message : e);
+    }
+  }
+
   public getCpfpInfo(req: Request, res: Response) {
     if (!/^[a-fA-F0-9]{64}$/.test(req.params.txId)) {
       res.status(501).send(`Invalid transaction ID.`);