Add testmempoolaccept API endpoint

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

@@ -1,4 +1,4 @@
-import { IBitcoinApi } from './bitcoin-api.interface';
+import { IBitcoinApi, TestMempoolAcceptResult } from './bitcoin-api.interface';
 import { IEsploraApi } from './esplora-api.interface';
 
 export interface AbstractBitcoinApi {
@@ -22,6 +22,7 @@ export interface AbstractBitcoinApi {
   $getScriptHash(scripthash: string): Promise<IEsploraApi.ScriptHash>;
   $getScriptHashTransactions(address: string, lastSeenTxId: string): Promise<IEsploraApi.Transaction[]>;
   $sendRawTransaction(rawTransaction: string): Promise<string>;
+  $testMempoolAccept(rawTransactions: string[], maxfeerate?: number): Promise<TestMempoolAcceptResult[]>;
   $getOutspend(txId: string, vout: number): Promise<IEsploraApi.Outspend>;
   $getOutspends(txId: string): Promise<IEsploraApi.Outspend[]>;
   $getBatchedOutspends(txId: string[]): Promise<IEsploraApi.Outspend[][]>;

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

@@ -205,3 +205,16 @@ export namespace IBitcoinApi {
     "utxo_size_inc": number;
   }
 }
+
+export interface TestMempoolAcceptResult {
+  txid: string,
+  wtxid: string,
+  allowed?: boolean,
+  vsize?: number,
+  fees?: {
+    base: number,
+    "effective-feerate": number,
+    "effective-includes": string[],
+  },
+  ['reject-reason']?: string,
+}

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

@@ -1,6 +1,6 @@
 import * as bitcoinjs from 'bitcoinjs-lib';
 import { AbstractBitcoinApi, HealthCheckHost } from './bitcoin-api-abstract-factory';
-import { IBitcoinApi } from './bitcoin-api.interface';
+import { IBitcoinApi, TestMempoolAcceptResult } from './bitcoin-api.interface';
 import { IEsploraApi } from './esplora-api.interface';
 import blocks from '../blocks';
 import mempool from '../mempool';
@@ -174,6 +174,14 @@ class BitcoinApi implements AbstractBitcoinApi {
     return this.bitcoindClient.sendRawTransaction(rawTransaction);
   }
 
+  async $testMempoolAccept(rawTransactions: string[], maxfeerate?: number): Promise<TestMempoolAcceptResult[]> {
+    if (rawTransactions.length) {
+      return this.bitcoindClient.testMempoolAccept(rawTransactions, maxfeerate ?? undefined);
+    } else {
+      return [];
+    }
+  }
+
   async $getOutspend(txId: string, vout: number): Promise<IEsploraApi.Outspend> {
     const txOut = await this.bitcoindClient.getTxOut(txId, vout, false);
     return {

backend/src/api/bitcoin/bitcoin.routes.ts

@@ -55,6 +55,7 @@ class BitcoinRoutes {
           .get(config.MEMPOOL.API_URL_PREFIX + 'mempool/recent', this.getRecentMempoolTransactions)
           .get(config.MEMPOOL.API_URL_PREFIX + 'tx/:txId', this.getTransaction)
           .post(config.MEMPOOL.API_URL_PREFIX + 'tx', this.$postTransaction)
+          .post(config.MEMPOOL.API_URL_PREFIX + 'txs/test', this.$testTransactions)
           .get(config.MEMPOOL.API_URL_PREFIX + 'tx/:txId/hex', this.getRawTransaction)
           .get(config.MEMPOOL.API_URL_PREFIX + 'tx/:txId/status', this.getTransactionStatus)
           .get(config.MEMPOOL.API_URL_PREFIX + 'tx/:txId/outspends', this.getTransactionOutspends)
@@ -749,6 +750,19 @@ class BitcoinRoutes {
     }
   }
 
+  private async $testTransactions(req: Request, res: Response) {
+    res.setHeader('content-type', 'text/plain');
+    try {
+      const rawTxs = Common.getTransactionsFromRequest(req);
+      const maxfeerate = parseFloat(req.query.maxfeerate as string);
+      const result = await bitcoinApi.$testMempoolAccept(rawTxs, maxfeerate);
+      res.send(result);
+    } catch (e: any) {
+      res.status(400).send(e.message && e.code ? 'testmempoolaccept RPC error: ' + JSON.stringify({ code: e.code, message: e.message })
+        : (e.message || 'Error'));
+    }
+  }
+
 }
 
 export default new BitcoinRoutes();

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

@@ -5,6 +5,7 @@ import { AbstractBitcoinApi, HealthCheckHost } from './bitcoin-api-abstract-fact
 import { IEsploraApi } from './esplora-api.interface';
 import logger from '../../logger';
 import { Common } from '../common';
+import { TestMempoolAcceptResult } from './bitcoin-api.interface';
 
 interface FailoverHost {
   host: string,
@@ -327,6 +328,10 @@ class ElectrsApi implements AbstractBitcoinApi {
     throw new Error('Method not implemented.');
   }
 
+  $testMempoolAccept(rawTransactions: string[], maxfeerate?: number): Promise<TestMempoolAcceptResult[]> {
+    throw new Error('Method not implemented.');
+  }
+
   $getOutspend(txId: string, vout: number): Promise<IEsploraApi.Outspend> {
     return this.failoverRouter.$get<IEsploraApi.Outspend>('/tx/' + txId + '/outspend/' + vout);
   }

backend/src/api/common.ts

@@ -946,6 +946,29 @@ export class Common {
     return this.validateTransactionHex(matches[1].toLowerCase());
   }
 
+  static getTransactionsFromRequest(req: Request): string[] {
+    if (typeof req.body !== 'string') {
+      throw Object.assign(new Error('Non-string request body'), { code: -1 });
+    }
+
+    const txs = req.body.split(',');
+
+    return txs.map(rawTx => {
+      // Support both upper and lower case hex
+      // Support both txHash= Form and direct API POST
+      const reg = /^((?:[a-fA-F0-9]{2})+)$/;
+      const matches = reg.exec(rawTx);
+      if (!matches || !matches[1]) {
+        throw Object.assign(new Error('Invalid hex string'), { code: -2 });
+      }
+
+      // Guaranteed to be a hex string of multiple of 2
+      // Guaranteed to be lower case
+      // Guaranteed to pass validation (see function below)
+      return this.validateTransactionHex(matches[1].toLowerCase());
+    });
+  }
+
   private static validateTransactionHex(txhex: string): string {
     // Do not mutate txhex