consolidateStreamedResponseBytes function

Future<Uint8List> consolidateStreamedResponseBytes(StreamedResponse response, { BytesReceivedCallback? onBytesReceived, })

Efficiently converts the response body of an StreamedResponse into a Uint8List.

The future returned will forward any error emitted by response.

The onBytesReceived callback, if specified, will be invoked for every chunk of bytes that is received while consolidating the response bytes. If the callback throws an error, processing of the response will halt, and the returned future will complete with the error that was thrown by the callback. For more information on how to interpret the parameters to the callback, see the documentation on BytesReceivedCallback.

Implementation

Future<Uint8List> consolidateStreamedResponseBytes(
  StreamedResponse response, {
  BytesReceivedCallback? onBytesReceived,
}) {
  final Completer<Uint8List> completer = Completer<Uint8List>.sync();

  final _OutputBuffer output = _OutputBuffer();
  ByteConversionSink sink = output;
  int? expectedContentLength = response.contentLength;
  if (expectedContentLength == -1) {
    expectedContentLength = null;
  }

  int bytesReceived = 0;
  late final StreamSubscription<List<int>> subscription;
  subscription = response.stream.listen((List<int> chunk) {
    sink.add(chunk);
    if (onBytesReceived != null) {
      bytesReceived += chunk.length;
      try {
        onBytesReceived(bytesReceived, expectedContentLength);
      } catch (error, stackTrace) {
        completer.completeError(error, stackTrace);
        subscription.cancel();
        return;
      }
    }
  }, onDone: () {
    sink.close();
    completer.complete(output.bytes);
  }, onError: completer.completeError, cancelOnError: true);

  return completer.future;
}