Question|Feature: Sending Binary Metadata

[nevi-me]

The grpc spec allows for sending metadata-bin as binary metadata. Is this currently supported?

v0.4.0

Repro steps

1. Create a grpc-dart client to connect to a server

2. Create a client call including a binary metadata key with a text value

    channel.stub.myMethod(new Request(), options: new CallOptions(metadata: {
      "testmetadata": "a string",
      "testmetadata-bin": "supposed to be binary"
    }, timeout: new Duration(seconds: 15))).then((Response response) {
      print(response);
    }).catchError((GrpcError error) {
      print("******* ${error.message} ******");
    });

Expected result: The request should either throw an error about malformed *-bin metadata, or discard the metadata

Actual result: The request sends the metadata, but there's a failure on the server (tested with NodeJS and Java)

Details

The request seems to silently fail on both NodeJS and Java, I tried getting log output, but couldn't find anything. I use nghttpx as my proxy, and it passed the testmetadata-bin as I supplied it.

One of the reasons why I use binary metadata is to pass my custom error messages as protobuf messages. I suppose it's a question for another day, but how would I deal with bytedata in dart? Do I use Uint8List?

[nevi-me]

I forgot to mention, removing the binary metadata field results in a successful call.

As a side note, flutter with gRPC is a dream so far! I'm rewriting an Android app that I gave up on after over a month, and within 2 days, I'm about 70% done with the same spec app using Flutter!

[jakobr-google]

Byte data in Dart is a Uint8List, yes.

There's currently no special support for binary metadata, so with the current code, you'll need to base64-encode the data yourself. Something like:

metadata: { 'testmetadata-bin': base64.encode(binaryData) }

(where base64 is from dart:convert)

I'll keep this issue open to provide better support for binary metadata.

[gedw99]

+1. i need this too. Prefer not ot have to base64 it :)

[nevi-me]

@gedw99 from my understanding, you can successfully send binary metadata, the library doesn't yet go the extra mile of checking whether a *-bin contains binary data, but it shouldn't stop us from using binary metadata.

[gedw99]

Ah. Not so bad..any chance you can link to an example of sniffing for this from a dart function ?

…

On Wed, May 9, 2018, 7:15 PM Neville Dipale ***@***.***> wrote: @gedw99 <https://github.com/gedw99> from my understanding, you can successfully send binary metadata, the library doesn't yet go the extra mile of checking whether a *-bin contains binary data, but it shouldn't stop us from using binary metadata. — You are receiving this because you were mentioned. Reply to this email directly, view it on GitHub <#72 (comment)>, or mute the thread <https://github.com/notifications/unsubscribe-auth/ATuCwuGzKDHeXk6BSvIKbXUxc_eYeRkAks5twyQXgaJpZM4S56Vg> .