Jersey client upload progress

In Jersey 2.X, i've used a WriterInterceptor to wrap the output stream with a subclass of Apache Commons IO CountingOutputStream that tracks the writing and notify my upload progress code (not shown).

public class UploadMonitorInterceptor implements WriterInterceptor {

    @Override
    public void aroundWriteTo(WriterInterceptorContext context) throws IOException, WebApplicationException {

        // the original outputstream jersey writes with
        final OutputStream os = context.getOutputStream();

        // you can use Jersey's target/builder properties or 
        // special headers to set identifiers of the source of the stream
        // and other info needed for progress monitoring
        String id = (String) context.getProperty("id");
        long fileSize = (long) context.getProperty("fileSize");

        // subclass of counting stream which will notify my progress
        // indicators.
        context.setOutputStream(new MyCountingOutputStream(os, id, fileSize));

        // proceed with any other interceptors
        context.proceed();
    }

}

I then registered this interceptor with the client, or with specific targets where you want to use the interceptor.

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);