Adding optional Blockstream esplora backend support.

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

@@ -0,0 +1,99 @@
+const config = require('../../../mempool-config.json');
+import { ITransaction, IMempoolInfo, IBlock } from '../../interfaces';
+import { AbstractBitcoinApi } from './bitcoin-api-abstract-factory';
+import axios, { AxiosResponse } from 'axios';
+
+class EsploraApi implements AbstractBitcoinApi {
+  client: any;
+
+  constructor() {
+    this.client = axios.create({
+      baseURL: config.ESPLORA_API_URL,
+      timeout: 15000,
+    });
+  }
+
+  getMempoolInfo(): Promise<IMempoolInfo> {
+    return new Promise(async (resolve, reject) => {
+      try {
+        const response: AxiosResponse = await this.client.get('/mempool');
+        resolve({
+          size: response.data.count,
+          bytes: response.data.vsize,
+        });
+      } catch (error) {
+        reject(error);
+      }
+    });
+  }
+
+  getRawMempool(): Promise<ITransaction['txid'][]> {
+    return new Promise(async (resolve, reject) => {
+      try {
+        const response: AxiosResponse = await this.client.get('/mempool/txids');
+        resolve(response.data);
+      } catch (error) {
+        reject(error);
+      }
+    });
+  }
+
+  getRawTransaction(txId: string): Promise<ITransaction> {
+    return new Promise(async (resolve, reject) => {
+      try {
+        const response: AxiosResponse = await this.client.get('/tx/' + txId);
+
+        response.data.vsize = response.data.size;
+        response.data.size = response.data.weight;
+        response.data.fee = response.data.fee / 100000000;
+
+        resolve(response.data);
+      } catch (error) {
+        reject(error);
+      }
+    });
+  }
+
+  getBlockCount(): Promise<number> {
+    return new Promise(async (resolve, reject) => {
+      try {
+        const response: AxiosResponse = await this.client.get('/blocks/tip/height');
+        resolve(response.data);
+      } catch (error) {
+        reject(error);
+      }
+    });
+  }
+
+  getBlock(hash: string): Promise<IBlock> {
+    return new Promise(async (resolve, reject) => {
+      try {
+        const blockInfo: AxiosResponse = await this.client.get('/block/' + hash);
+        const blockTxs: AxiosResponse = await this.client.get('/block/' + hash + '/txids');
+
+        const block = blockInfo.data;
+        block.hash = hash;
+        block.nTx = block.tx_count;
+        block.time = block.timestamp;
+        block.tx = blockTxs.data;
+
+        resolve(block);
+      } catch (error) {
+        reject(error);
+      }
+    });
+  }
+
+  getBlockHash(height: number): Promise<string> {
+    return new Promise(async (resolve, reject) => {
+      try {
+        const response: AxiosResponse = await this.client.get('/block-height/' + height);
+        resolve(response.data);
+      } catch (error) {
+        reject(error);
+      }
+    });
+  }
+}
+
+export default EsploraApi;