gwt-websockets

A simple library to provide web sockets support to GWT.

Quick Start

The simplest way to use the library is to add the following dependency into the build system. i.e.

<dependency>
   <groupId>org.realityforge.gwt.websockets</groupId>
   <artifactId>gwt-websockets</artifactId>
   <version>1.2</version>
   <scope>provided</scope>
</dependency>

Then you add the following snippet into the .gwt.xml file.

<module rename-to='myapp'>
  ...

  <!-- Enable the websocket library -->
  <inherits name="org.realityforge.gwt.websockets.WebSockets"/>
</module>

Then you can interact with the WebSocket from within the browser.

final WebSocket webSocket = WebSocket.newWebSocketIfSupported();
if ( null != webSocket )
{
  webSocket.setListener( new WebSocketListenerAdapter()
  {
    @Override
    public void onOpen( final WebSocket webSocket )
    {
      // After we have connected we can send
      webSocket.send( "Hello!" );
    }

    @Override
    public void onMessage( final WebSocket webSocket, final String data )
    {
      // After we receive a message back we can close the socket
      webSocket.close();
    }
  } );
  webSocket.connect( "ws://localhost/ws/echo" );
}

This should be sufficient to put together a simple WebSocket application.

A very simple example of this code is available in the gwt-websockets-example project.

TODO

• Consider supporting a Blob object from the HTML5 File API with send and receive.

Appendix

• Mozilla WebSockets Document
• RFC6455: The WebSocket Protocol