Question

I have a jersey client that need to upload a file big enough to require a progress bar.
The problem is that, for an upload that requires some minutes, i see the bytes transfered to go to 100% as soon as the application has started. Then it takes some minutes to print the “on finished” string.
It is as if the bytes were sent to a buffer, and i was reading the transfert-to-the buffer speed instead of the actual upload speed. This makes the progress bar useless.

This is the very simple code:

ClientConfig config = new DefaultClientConfig();
Client client = Client.create(config);
WebResource resource = client.resource("www.myrestserver.com/uploads");
WebResource.Builder builder = resource.type(MediaType.MULTIPART_FORM_DATA_TYPE);

FormDataMultiPart multiPart = new FormDataMultiPart();
FileDataBodyPart fdbp = new FileDataBodyPart("data.zip", new File("data.zip"));
BodyPart bp = multiPart.bodyPart(fdbp);
String response = builder.post(String.class, multiPart);

To get progress state i’ve added a ContainerListener filter, obviouslt before calling builder.post:

final ContainerListener containerListener = new ContainerListener() {

        @Override
        public void onSent(long delta, long bytes) {
            System.out.println(delta + " : " + long);
        }

        @Override
        public void onFinish() {
            super.onFinish();
            System.out.println("on finish");
        }

    };

    OnStartConnectionListener connectionListenerFactory = new OnStartConnectionListener() {
        @Override
        public ContainerListener onStart(ClientRequest cr) {
            return containerListener;
        }

    };

    resource.addFilter(new ConnectionListenerFilter(connectionListenerFactory));

Answer 1

it should be enough to provide you own MessageBodyWriter for java.io.File which fires some events or notifies some listeners as progress changes

@Provider()
@Produces(MediaType.APPLICATION_OCTET_STREAM)
public class MyFileProvider implements MessageBodyWriter<File> {

    public boolean isWriteable(Class<?> type, Type genericType, Annotation[] annotations, MediaType mediaType) {
        return File.class.isAssignableFrom(type);
    }

    public void writeTo(File t, Class<?> type, Type genericType, Annotation annotations[], MediaType mediaType, MultivaluedMap<String, Object> httpHeaders, OutputStream entityStream) throws IOException {
        InputStream in = new FileInputStream(t);
        try {
            int read;
            final byte[] data = new byte[ReaderWriter.BUFFER_SIZE];
            while ((read = in.read(data)) != -1) {
                entityStream.write(data, 0, read);
                // fire some event as progress changes
            }
        } finally {
            in.close();
        }
    }

    @Override
    public long getSize(File t, Class<?> type, Type genericType, Annotation[] annotations, MediaType mediaType) {
        return t.length();
    }
}

and to make your client application uses this new provider simply:

ClientConfig config = new DefaultClientConfig();
config.getClasses().add(MyFileProvider.class);

or

ClientConfig config = new DefaultClientConfig();
MyFileProvider myProvider = new MyFileProvider ();
cc.getSingletons().add(myProvider);

You would have to also include some algorithm to recognize which file is transfered when receiving progress events.

Edited:

I just found that by default HTTPUrlConnection uses buffering. And to disable buffering you could do couple of things:

1. httpUrlConnection.setChunkedStreamingMode(chunklength) – disables buffering and uses chunked transfer encoding to send request
2. httpUrlConnection.setFixedLengthStreamingMode(contentLength) – disables buffering and but ads some constraints to streaming: exact number of bytes must be sent

So I suggest the final solution to your problem uses 1st option and would look like this:

ClientConfig config = new DefaultClientConfig();
config.getClasses().add(MyFileProvider.class);
URLConnectionClientHandler clientHandler = new URLConnectionClientHandler(new HttpURLConnectionFactory() {
     @Override
     public HttpURLConnection getHttpURLConnection(URL url) throws IOException {
           HttpURLConnection connection = (HttpURLConnection) url.openConnection();
                connection.setChunkedStreamingMode(1024);
                return connection;
            }
});
Client client = new Client(clientHandler, config);