RNFS.stopDownload never calls errorCallback()

[michaelmeyers]

Issue

Related Issues: #781, #638, #568,

When running RNFS.stopDownload a callBack with the information that the download has been terminated is never sent.
iOS appears to never return nil for this function cancelByProducingResumeData(void (^)(NSData*resumeData))completionHandler
If this function does not return nil, when the developer does not want/need the download to be resumable, the errorCallback() will never get called.

@Downloader.m

...
- (void)stopDownload
{
  if (_task.state == NSURLSessionTaskStateRunning) {
    [_task cancelByProducingResumeData:^(NSData * _Nullable resumeData) {
        if (resumeData != nil) {
            self.resumeData = resumeData;
            if (self->_params.resumableCallback) {
                self->_params.resumableCallback();
            }
        } else {
            NSError *error = [NSError errorWithDomain:@"RNFS"
                              code:0 //used to pass an NSString @"Aborted" here, but it needs an NSInteger
                              userInfo:@{
                              NSLocalizedDescriptionKey: @"Download has been aborted"
            }];
            self->_params.errorCallback(error);
        }
    }];
  }
}
...

Environment:

System:
    OS: macOS Mojave 10.14.6
    CPU: (8) x64 Intel(R) Core(TM) i7-6700HQ CPU @ 2.60GHz
    Memory: 80.18 MB / 16.00 GB
    Shell: 3.2.57 - /bin/bash
  Binaries:
    Node: 11.2.0 - /usr/local/bin/node
    npm: 6.4.1 - /usr/local/bin/npm
    Watchman: 4.9.0 - /usr/local/bin/watchman
  SDKs:
    iOS SDK:
      Platforms: iOS 13.2, DriverKit 19.0, macOS 10.15, tvOS 13.2, watchOS 6.1
  IDEs:
    Xcode: 11.3/11C29 - /usr/bin/xcodebuild
  npmPackages:
    react: 16.9.0 => 16.9.0 
    react-native: 0.61.4 => 0.61.4
    react-native-fs: 2.14.1
  npmGlobalPackages:
    react-native-cli: 2.0.1
    react-native: 0.59.8

Solution

It doesn't appear that the errorCallback() and the resumableCallback() need to be mutually exclusive. My fix removes the else and always called the errorCallBack().

Downloader.m

...
- (void)stopDownload
{
  if (_task.state == NSURLSessionTaskStateRunning) {
    [_task cancelByProducingResumeData:^(NSData * _Nullable resumeData) {
      NSLog(@"RNFS.stopDownload");
        if (resumeData != nil) {
            NSLog(@"RNFS.stopDownload resumeData does not equal nil");
            self.resumeData = resumeData;
            if (self->_params.resumableCallback) {
                self->_params.resumableCallback();
            }
        }
        NSError *error = [NSError errorWithDomain:@"RNFS"
                                  code:0 //used to pass an NSString @"Aborted" here, but it needs an NSInteger
                                  userInfo:@{
                                  NSLocalizedDescriptionKey: @"Download has been aborted"
        }];
        NSLog(@"RNFS.stopDownload send terminated error");
        self->_params.errorCallback(error);
    }];
  }
}
...

The error being passed states "Download has been aborted" and whether there is resumableData or not, the @Aborted error should be thrown.

[newfylox]

Your solution works for me. I'm using it with patch-package until they release a new version. It might fix #568 as well.

Thanks