Unable to send/receive binary data (e.g. Buffer, Uint8List) in HTTPS function

[paulreimer]

This works with node_interop and Google Cloud Function (binary data is returned in the response):

Uint8List responseBytes = ...;
res
  ..statusCode = 200 // OK
  ..write(Buffer.from(responseBytes))
  ..end();

But with firebase-functions-interop it returns the toString representation of a List<int> of the binary data:

Uint8List responseBytes = ...;
request.response
  ..statusCode = 200 // OK
  ..write(Buffer.from(responseBytes))
  ..close();

Produces the output:

[24, 0, 0, 0, 65, 67, 77, 46, 16,...]

[pulyaevskiy]

The ‘write’ method is supposed to only write string values. Everything that is not a ‘String’, gets converted with ‘toString()’ call. This contract comes from the Dart’s IOSink class, actually, node_io simply tries to follow it. Docs: https://api.dartlang.org/dev/2.0.0-dev.63.0/dart-io/IOSink/write.html

To add byte data there is ‘add’ method.

Hope this helps.

[pulyaevskiy]

Oh, the first example shouldn’t work either. This is strange since firebase functions use the same node_io implementation.

[paulreimer]

Well, oddly the first example does work! Maybe the Buffer.from(...) is affecting things? But using add also works in both cases (so it does resolve this issue for me!).

In fact I no longer need the package:node_interop:buffer.dart dependency and I can add my Uint8List bytes directly.

Thanks so much for the help!

[pulyaevskiy]

Glad it works for you now.

Wondering if you can provide a more complete version of the first example? Would be nice to figure out what's going on there.