Writing a Source to multiple Okhttp request.

Im aware this is a strange requirement but hear me out. Lets imagine I’m reading binary data from a hardware sensor, like a microphone, so I wrap that in a Source. Then I’m sending this data across the wire via Okhttp.

Source source = AudioSource.getThreeSeconds();
server.sendDataToMicrosoftVoiceRecogniser(source, callback);

Because we want to stream the data when the web request starts. we use the Recipe for post streaming from Okhttp.

void sendDataToMicrosoftVoiceRecogniser(Source sources, Callback callback){
   RequestBody requestBody = new RequestBody() {
               @Override public MediaType contentType() {
                    return MediaType.parse("application/octet-stream");
                }

                @Override public void writeTo(final BufferedSink sink) throws IOException {
                    sink.write(source);
                }
    };

    Request request = new Request.Builder()
        .url("https://api.github.com/markdown/raw")
        .post(requestBody)
        .build();

    Response response = client.newCall(request). enqueue(callback);
...
}

How can I stream the same data to multiple API’s in parallel. I.E

Source source = AudioSource.getSource();

server.sendDataToMicrosoftVoiceRecogniser(source, callback);
server.sendDataToMyServer(source, callback);

The first request consumes the bytes then the second receives random data. I have managed to get this to work by:

public static Source tee(final Source source, final Buffer copy) {
        return new Source() {
            @Override public long read(final Buffer sink, final long byteCount) throws IOException {
                final long bytesRead = source.read(sink, byteCount);
                if (bytesRead > 0) {
                    sink.copyTo(copy, sink.size() - bytesRead, bytesRead);
                }
                return bytesRead;
            }

            @Override public Timeout timeout() {
                return source.timeout();
            }

            @Override public void close() throws IOException {
                source.close();
            }
        };
    }

final Source source = AudioSource.getSource();

final Buffer buffer = new Buffer();
final Source speechToText = tee(source, trigger);

server.sendDataToMicrosoftVoiceRecogniser(speechToText, callback);
server.sendDataToMyServer(source, buffer);

This has its problems, as if the web requests consume data at different speeds the buffer can be emptied, I get round this by knowing how much data “server.sendDataToMyServer” expects.

Any ideas on how I could do this? I suppose what I really need is a Mirrored source that buffers the bytes emitted from another Source until they are consumed again.

[RoryKelly]

Github should have a “buy me a beer option”. Thanks!

[swankjesse]

(putting synchronized outside of while is probably okay)