Allow retries after failed resized image downloads

flutter_cache_manager/CHANGELOG.md

@@ -1,3 +1,7 @@
+## [3.5.1] - 2026-11-05
+
+* Allows failed resized-image downloads to be retried by clearing completed resize streams ([#439](https://github.com/Baseflow/flutter_cache_manager/issues/439)).
+
 ## [3.5.0] - 2026-11-04
 
 * **DEPRECATION** Deprecates `supportedFileNames`: whether an image is resized is now decided by the image engine from the file's content instead of from the file extension derived from the `Content-Type` header of the response ([#475](https://github.com/Baseflow/flutter_cache_manager/pull/475))

flutter_cache_manager/lib/src/cache_managers/image_cache_manager.dart

@@ -62,19 +62,21 @@ mixin ImageCacheManager on BaseCacheManager {
     }
     var runningResize = _runningResizes[resizedKey];
     if (runningResize == null) {
-      runningResize = _fetchedResizedFile(
-        url,
-        key,
+      runningResize = _trackResizeStream(
         resizedKey,
-        headers,
-        withProgress,
-        maxWidth: maxWidth,
-        maxHeight: maxHeight,
-      ).asBroadcastStream();
+        _fetchedResizedFile(
+          url,
+          key,
+          resizedKey,
+          headers,
+          withProgress,
+          maxWidth: maxWidth,
+          maxHeight: maxHeight,
+        ),
+      );
       _runningResizes[resizedKey] = runningResize;
     }
     yield* runningResize;
-    _runningResizes.remove(resizedKey);
   }
 
   final Map<String, Stream<FileResponse>> _runningResizes = {};
@@ -89,6 +91,34 @@ mixin ImageCacheManager on BaseCacheManager {
   /// when the manager instance is recreated.
   final Set<String> _notResizableKeys = {};
 
+  Stream<FileResponse> _trackResizeStream(
+    String resizedKey,
+    Stream<FileResponse> stream,
+  ) {
+    // Clear the in-flight entry on both success and error so failures can be
+    // retried by a later request.
+    late final Stream<FileResponse> trackedStream;
+    trackedStream = stream
+        .transform(
+          StreamTransformer<FileResponse, FileResponse>.fromHandlers(
+            handleError: (Object error, StackTrace stackTrace, sink) {
+              if (identical(_runningResizes[resizedKey], trackedStream)) {
+                _runningResizes.remove(resizedKey);
+              }
+              sink.addError(error, stackTrace);
+            },
+            handleDone: (sink) {
+              if (identical(_runningResizes[resizedKey], trackedStream)) {
+                _runningResizes.remove(resizedKey);
+              }
+              sink.close();
+            },
+          ),
+        )
+        .asBroadcastStream();
+    return trackedStream;
+  }
+
   Stream<FileResponse> _fetchedResizedFile(
     String url,
     String originalKey,

flutter_cache_manager/pubspec.yaml

@@ -1,6 +1,6 @@
 name: flutter_cache_manager
 description: Generic cache manager for flutter. Saves web files on the storages of the device and saves the cache info using sqflite.
-version: 3.5.0
+version: 3.5.1
 homepage: https://github.com/Baseflow/flutter_cache_manager
 topics:
   - cache

flutter_cache_manager/test/image_cache_manager_test.dart

@@ -5,9 +5,11 @@ import 'dart:ui';
 import 'package:flutter/material.dart';
 import 'package:flutter_cache_manager/flutter_cache_manager.dart';
 import 'package:flutter_test/flutter_test.dart';
+import 'package:mockito/mockito.dart';
 
 import 'cache_manager_test.dart';
 import 'helpers/config_extensions.dart';
+import 'helpers/mock_file_fetcher_response.dart';
 import 'helpers/test_configuration.dart';
 import 'test_images.dart';
 
@@ -72,6 +74,51 @@ void main() {
     );
   });
   group('Test resized image caching', () {
+    test('Failed resize download can be retried', () async {
+      final config = createTestConfig();
+      final cacheManager = TestCacheManager(config);
+      var downloadCount = 0;
+      when(
+        config.mockFileService.get(fileUrl, headers: anyNamed('headers')),
+      ).thenAnswer((_) async {
+        downloadCount++;
+        if (downloadCount == 1) {
+          return MockFileFetcherResponse(
+            const Stream.empty(),
+            0,
+            null,
+            '',
+            404,
+            DateTime.now(),
+          );
+        }
+
+        final imageBytes = exampleImage;
+        return MockFileFetcherResponse(
+          Stream.value(imageBytes),
+          imageBytes.length,
+          'testv1',
+          '.png',
+          200,
+          DateTime.now().add(const Duration(days: 1)),
+        );
+      });
+
+      await expectLater(
+        cacheManager.getImageFile(fileUrl, maxHeight: 100).toList(),
+        throwsA(isA<HttpExceptionWithStatus>()),
+      );
+
+      final results = await cacheManager
+          .getImageFile(fileUrl, maxHeight: 100)
+          .timeout(const Duration(seconds: 1))
+          .toList();
+
+      expect(downloadCount, 2);
+      expect(results, hasLength(1));
+      expect(results.single, isA<FileInfo>());
+    });
+
     test('Resized image should be fetched from cache', () async {
       var config = await setupConfig(cacheKey: 'resized_w100_h80_$fileUrl');
       var cacheManager = TestCacheManager(config);