Track and display purged transaction status

backend/src/api/mempool.ts

@@ -16,6 +16,7 @@ class Mempool {
   private inSync: boolean = false;
   private mempoolCacheDelta: number = -1;
   private mempoolCache: { [txId: string]: TransactionExtended } = {};
+  private minFeeMempool: { [txId: string]: boolean } = {};
   private mempoolInfo: IBitcoinApi.MempoolInfo = { loaded: false, size: 0, bytes: 0, usage: 0, total_fee: 0,
                                                     maxmempool: 300000000, mempoolminfee: 0.00001000, minrelaytxfee: 0.00001000 };
   private mempoolChangedCallback: ((newMempool: {[txId: string]: TransactionExtended; }, newTransactions: TransactionExtended[],
@@ -124,6 +125,7 @@ class Mempool {
     let hasChange: boolean = false;
     const currentMempoolSize = Object.keys(this.mempoolCache).length;
     const transactions = await bitcoinApi.$getRawMempool();
+    await this.updateMinFeeMempool();
     const diff = transactions.length - currentMempoolSize;
     const newTransactions: TransactionExtended[] = [];
 
@@ -232,6 +234,34 @@ class Mempool {
     logger.debug(`Mempool updated in ${time / 1000} seconds. New size: ${Object.keys(this.mempoolCache).length} (${diff > 0 ? '+' + diff : diff})`);
   }
 
+  public isTxPurged(txid: string): boolean {
+    return !this.minFeeMempool[txid];
+  }
+
+  private async updateMinFeeMempool() {
+    const minFeeTransactions = await bitcoinSecondClient.getRawMemPool();
+    const minFeeTxMap = {};
+    for (const txid of minFeeTransactions) {
+      minFeeTxMap[txid] = true;
+    }
+    const removed: string[] = [];
+    const added: string[] = [];
+    for (const txid of Object.keys(this.minFeeMempool)) {
+      if (!minFeeTxMap[txid]) {
+        removed.push(txid);
+      }
+    }
+    for (const txid of minFeeTransactions) {
+      if (!this.minFeeMempool[txid]) {
+        added.push(txid);
+        this.minFeeMempool[txid] = true;
+      }
+    }
+    for (const txid of removed) {
+      delete this.minFeeMempool[txid];
+    }
+  }
+
   public handleRbfTransactions(rbfTransactions: { [txid: string]: TransactionExtended; }) {
     for (const rbfTransaction in rbfTransactions) {
       if (this.mempoolCache[rbfTransaction]) {

backend/src/api/websocket-handler.ts

@@ -19,6 +19,7 @@ import BlocksAuditsRepository from '../repositories/BlocksAuditsRepository';
 import BlocksSummariesRepository from '../repositories/BlocksSummariesRepository';
 import Audit from './audit';
 import { deepClone } from '../utils/clone';
+import mempool from './mempool';
 import priceUpdater from '../tasks/price-updater';
 import { ApiPrice } from '../repositories/PricesRepository';
 
@@ -92,6 +93,9 @@ class WebsocketHandler {
                   }
                 }
               }
+              if (config.MEMPOOL.USE_SECOND_NODE_FOR_MINFEE && memPool.getMempool()[client['track-tx']]) {
+                response['txPurged'] = memPool.isTxPurged(client['track-tx']);
+              }
             } else {
               client['track-tx'] = null;
             }
@@ -395,6 +399,11 @@ class WebsocketHandler {
             }
           }
         }
+
+        // update purge status of unconfirmed tracked txs
+        if (config.MEMPOOL.USE_SECOND_NODE_FOR_MINFEE && newMempool[client['track-tx']]) {
+          response['txPurged'] = memPool.isTxPurged(client['track-tx']);
+        }
       }
 
       if (client['track-mempool-block'] >= 0) {