CODEWITHSUNDEEP
firebaseflutterdartfirebase-storageflutter-dependencies
BenMilanko
BenMilanko

Reputation: 31

How to cache images from Firebase in Flutter?

I'm trying to access images in Firebase Storage and cache them locally on the device.

My current attempt uses flutter_cache_manager. The documentation states:

Most common file service will be an [HttpFileService], however one can also make something more specialized. For example you could fetch files from other apps or from local storage.

class HttpFileService implements FileService {
  http.Client _httpClient;
  HttpFileService({http.Client httpClient}) {
    _httpClient = httpClient ?? http.Client();
  }

  @override
  Future<FileServiceResponse> get(String url,
      {Map<String, String> headers = const {}}) async {
    final req = http.Request('GET', Uri.parse(url));
    req.headers.addAll(headers);
    final httpResponse = await _httpClient.send(req);

return HttpGetResponse(httpResponse);

  }
}

I've tried to extend this class to process the URL for Firebase

class FirebaseHttpFileService extends HttpFileService {
  @override
  Future<FileServiceResponse> get(String url, {Map<String, String> headers = const {}}) async {

    var ref = FirebaseStorage.instance.ref().child(url);
    var _url = await ref.getDownloadURL() as String;

    return super.get(_url);
  }
}

And extend the BaseCacheManager using a template from the GitHub repo, replacing the file service with my new one.

class FirebaseCacheManager extends BaseCacheManager {
  static const key = "firebaseCache";

  static FirebaseCacheManager _instance;

  factory FirebaseCacheManager() {
    if (_instance == null) {
      _instance = new FirebaseCacheManager._();
    }
    return _instance;
  }

  FirebaseCacheManager._() : super(key,
      maxAgeCacheObject: Duration(days: 7),
      maxNrOfCacheObjects: 20,
      fileService: FirebaseHttpFileService());

  Future<String> getFilePath() async {
    var directory = await getTemporaryDirectory();
    return p.join(directory.path, key);
  }
}

But I get the following error:

setState() called after dispose(): _ImageState#50d41(lifecycle state: defunct, not mounted, stream: ImageStream#ac6d5(MultiFrameImageStreamCompleter#0c956, [2448×3264] @ 1.0x, 3 listeners), pixels: null, loadingProgress: null, frameNumber: null, wasSynchronouslyLoaded: false)

I can process the URL before attempting to retrieve the file but that needlessly wastes time. I've also tried to use other packages like Flutter Cache Image but it seems to crash the app after a short amount of time.

Thanks for any pointers in the right direction!

Upvotes: 2

Views: 4688

Answers (1)

BenMilanko
BenMilanko

Reputation: 31

This problem is actually tied to the errorWidget as seen in the issue here. The code is working if the error widget is commented out in CachedNetworkImage.

Upvotes: 1

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