Fix prefetch race condition, transaction observable leak, and media store getUrl crash

src/app/shared/dia-backend/asset/prefetching/dia-backend-asset-prefetching.service.ts

@@ -8,6 +8,8 @@ import { DiaBackendAssetDownloadingService } from '../downloading/dia-backend-do
   providedIn: 'root',
 })
 export class DiaBackendAssetPrefetchingService {
+  private readonly batchSize = 5;
+
   constructor(
     private readonly assetRepository: DiaBackendAssetRepository,
     private readonly downloadingService: DiaBackendAssetDownloadingService,
@@ -32,19 +34,22 @@ export class DiaBackendAssetPrefetchingService {
       if (diaBackendAssets.length === 0) {
         break;
       }
-      await Promise.all(
-        diaBackendAssets.map(async diaBackendAsset => {
-          if (diaBackendAsset.source_transaction === null)
-            await this.downloadingService.storeRemoteCapture(
-              diaBackendAsset,
-              (await this.mediaStore.getThumbnail(
-                diaBackendAsset.proof_hash
-              )) === undefined
-            );
-          currentCount += 1;
-          onStored(currentCount, totalCount);
-        })
-      );
+      for (let i = 0; i < diaBackendAssets.length; i += this.batchSize) {
+        const batch = diaBackendAssets.slice(i, i + this.batchSize);
+        await Promise.all(
+          batch.map(async diaBackendAsset => {
+            if (diaBackendAsset.source_transaction === null)
+              await this.downloadingService.storeRemoteCapture(
+                diaBackendAsset,
+                (await this.mediaStore.getThumbnail(
+                  diaBackendAsset.proof_hash
+                )) === undefined
+              );
+          })
+        );
+        currentCount += batch.length;
+        onStored(currentCount, totalCount);
+      }
       currentOffset += diaBackendAssets.length;
     }
   }

src/app/shared/dia-backend/transaction/dia-backend-transaction-repository.service.ts

@@ -1,7 +1,15 @@
 import { HttpClient, HttpParams } from '@angular/common/http';
 import { Injectable } from '@angular/core';
-import { BehaviorSubject, combineLatest, defer, forkJoin, Subject } from 'rxjs';
 import {
+  BehaviorSubject,
+  EMPTY,
+  combineLatest,
+  defer,
+  forkJoin,
+  Subject,
+} from 'rxjs';
+import {
+  catchError,
   concatMap,
   distinctUntilChanged,
   first,
@@ -86,7 +94,12 @@ export class DiaBackendTransactionRepository {
           this.assetDownloadingService.storeRemoteCapture(asset)
         )
       )
-    )
+    ),
+    catchError((err: unknown) => {
+      // eslint-disable-next-line no-console
+      console.error('downloadExpired$ error:', err);
+      return EMPTY;
+    })
   );
 
   constructor(

src/app/shared/media/media-store/media-store.service.ts

@@ -265,14 +265,20 @@ export class MediaStore {
    * directly when dealing with small image for better performance.
    */
   async getUrl(index: string, mimeType: MimeType) {
-    if (Capacitor.isNativePlatform()) {
-      // Workaround to fix urls (thumbnails) saved as incorrect mimeType.
-      await this.fixIncorrectExtension(index, mimeType);
-      return Capacitor.convertFileSrc(await this.getUri(index));
+    try {
+      if (Capacitor.isNativePlatform()) {
+        // Workaround to fix urls (thumbnails) saved as incorrect mimeType.
+        await this.fixIncorrectExtension(index, mimeType);
+        return Capacitor.convertFileSrc(await this.getUri(index));
+      }
+      return URL.createObjectURL(
+        await base64ToBlob(await this.readWithFileSystem(index), mimeType)
+      );
+    } catch (err: unknown) {
+      // eslint-disable-next-line no-console
+      console.error(`MediaStore.getUrl failed for index ${index}:`, err);
+      return '';
     }
-    return URL.createObjectURL(
-      await base64ToBlob(await this.readWithFileSystem(index), mimeType)
-    );
   }
 
   private async fixIncorrectExtension(