Server Side WebSocket in Java

I recently wrote a high quality, low grade, server side WebSocket (RFC 6455) implementation. The intended use-case is as follows:

• I want to create a service in Java that accepts connections from modern web browsers.
• I want to use InputStream and OutputStream to get my bytes back and forth between my service and the browser.
• I want my service code to do this with minimal setup.
• I want to ignore all the protocol details; just give me the bytes.
• I'm not sure, but I might like to support SSL/TLS security (i.e.: HTTPS) for none/some/all of my connections.

 

Need More?

If you need something else, like Java NIO support, non-blocking I/O, evented I/O, ability to provide custom handlers for web frames, etc.. then you'll probably need to find another implementation:

• http://stackoverflow.com/questions/4003102/best-java-framework-for-server-side-websockets
• http://stackoverflow.com/questions/4278456/websockets-production-ready-server-in-java
• http://stackoverflow.com/questions/4292624/java-websocket-host

Note that JavaEE 7 includes WebSocket support. So if you've already got a web container (i.e.: Tomcat), then you've probably already got a solution at hand:

• http://docs.oracle.com/javaee/7/api/javax/websocket/package-summary.html

 

Just Enough

Since you're still reading this, I'll assume you want to know more about my WebSocket implementation. You can find the repository here:

https://github.com/blinkdog/websocket

How does it work? I'm glad you asked...


This is how you start listening for WebSocket connections:

ServerSocket serverSocket = new ServerSocket(PORT);
WebSocketServerSocket webSocketServerSocket = new WebSocketServerSocket(serverSocket);
WebSocket webSocket = webSocketServerSocket.accept();

And this is how you read data from the connecting client:

InputStream is = webSocket.getInputStream();
int data = is.read();

And this is how you communicate back to the connecting client:

WebSocketServerOutputStream os = webSocket.getOutputStream();
os.writeString("This is a UTF-8 string.");
os.writeBinary("Some binary data.".getBytes()); 

That's It

A high quality, low grade, server-side WebSocket component with no frills or nonsense. That's it, that's all. Enjoy!