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[],
@@ -119,6 +120,7 @@ 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[] = [];
 
@@ -206,6 +208,34 @@ 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

@@ -20,6 +20,7 @@ import BlocksAuditsRepository from '../repositories/BlocksAuditsRepository';
 import BlocksSummariesRepository from '../repositories/BlocksSummariesRepository';
 import Audit from './audit';
 import { deepClone } from '../utils/clone';
+import mempool from './mempool';
 
 class WebsocketHandler {
   private wss: WebSocket.Server | undefined;
@@ -91,6 +92,9 @@ 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;
             }
@@ -394,6 +398,11 @@ 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) {

frontend/src/app/components/transaction/transaction.component.html

@@ -1,6 +1,10 @@
 <div class="container-xl">
 
   <div class="title-block">
+    <div *ngIf="isPurged" class="alert alert-mempool" role="alert">
+      <span i18n="transaction.purged|Purged from mempool">This transaction has been purged from our default sized 300MB mempool</span>
+    </div>
+
     <div *ngIf="rbfTransaction" class="alert alert-mempool" role="alert">
       <span i18n="transaction.rbf.replacement|RBF replacement">This transaction has been replaced by:</span>
       <app-truncate [text]="rbfTransaction.txid" [lastChars]="12" [link]="['/tx/' | relativeUrl, rbfTransaction.txid]"></app-truncate>

frontend/src/app/components/transaction/transaction.component.ts

@@ -43,6 +43,7 @@ export class TransactionComponent implements OnInit, AfterViewInit, OnDestroy {
   fetchRbfSubscription: Subscription;
   fetchCachedTxSubscription: Subscription;
   txReplacedSubscription: Subscription;
+  txPurgedSubscription: Subscription;
   blocksSubscription: Subscription;
   queryParamsSubscription: Subscription;
   urlFragmentSubscription: Subscription;
@@ -55,6 +56,7 @@ export class TransactionComponent implements OnInit, AfterViewInit, OnDestroy {
   fetchCpfp$ = new Subject<string>();
   fetchRbfHistory$ = new Subject<string>();
   fetchCachedTx$ = new Subject<string>();
+  isPurged: boolean = false;
   now = new Date().getTime();
   timeAvg$: Observable<number>;
   liquidUnblinding = new LiquidUnblinding();
@@ -359,6 +361,10 @@ export class TransactionComponent implements OnInit, AfterViewInit, OnDestroy {
       }
     });
 
+    this.txPurgedSubscription = this.stateService.txPurged$.subscribe((isPurged) => {
+      this.isPurged = isPurged;
+    });
+
     this.queryParamsSubscription = this.route.queryParams.subscribe((params) => {
       if (params.showFlow === 'false') {
         this.overrideFlowPreference = false;
@@ -494,6 +500,7 @@ export class TransactionComponent implements OnInit, AfterViewInit, OnDestroy {
     this.fetchRbfSubscription.unsubscribe();
     this.fetchCachedTxSubscription.unsubscribe();
     this.txReplacedSubscription.unsubscribe();
+    this.txPurgedSubscription.unsubscribe();
     this.blocksSubscription.unsubscribe();
     this.queryParamsSubscription.unsubscribe();
     this.flowPrefSubscription.unsubscribe();

frontend/src/app/interfaces/websocket.interface.ts

@@ -16,6 +16,7 @@ export interface WebsocketResponse {
   tx?: Transaction;
   rbfTransaction?: ReplacedTransaction;
   txReplaced?: ReplacedTransaction;
+  txPurged?: boolean;
   utxoSpent?: object;
   transactions?: TransactionStripped[];
   loadingIndicators?: ILoadingIndicators;

frontend/src/app/services/state.service.ts

@@ -94,6 +94,7 @@ export class StateService {
   mempoolBlockTransactions$ = new Subject<TransactionStripped[]>();
   mempoolBlockDelta$ = new Subject<MempoolBlockDelta>();
   txReplaced$ = new Subject<ReplacedTransaction>();
+  txPurged$ = new Subject<boolean>();
   utxoSpent$ = new Subject<object>();
   difficultyAdjustment$ = new ReplaySubject<DifficultyAdjustment>(1);
   mempoolTransactions$ = new Subject<Transaction>();

frontend/src/app/services/websocket.service.ts

@@ -261,6 +261,10 @@ export class WebsocketService {
       this.stateService.txReplaced$.next(response.txReplaced);
     }
 
+    if (response.txPurged != null) {
+      this.stateService.txPurged$.next(response.txPurged);
+    }
+
     if (response['mempool-blocks']) {
       this.stateService.mempoolBlocks$.next(response['mempool-blocks']);
     }