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.

[ghost]

+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.

[ghost]

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> .

[njovy]

Any new update regarding this?

[mraleph]

I am going to close this issue to reflect that no special work is planned here. There is nothing preventing you from sending binary metadata, you just need to base64 encode it manually.