There are many websocket server implementations. Any serious attempts at building in websockets into the application should look at libraries like http://libwebsockets.org/ or wrappers on such. But a small lightweight implementation of your own, specific to your applications is good and fun. Here's a very simplistic one I made, while reading through the rather simple websocket protocol.
The websocket connection starts as a regular HTTP connection from the client, with certain headers that indicate that the client is requesting a websocket connection. The server responds with specific response headers if it accepts the connection. Subsequent messages flow in either direction. Messages are framed with a few bytes of header data that can contain the type of data, data length and a basic XOR mask. Longer messages are broken up into multiple frames.
Details at:
This sample websocket implementation here just broadcasts messages from any connected client to all connected clients, like a group chat application.
The websocket connection starts as a regular HTTP connection from the client, with certain headers that indicate that the client is requesting a websocket connection. The server responds with specific response headers if it accepts the connection. Subsequent messages flow in either direction. Messages are framed with a few bytes of header data that can contain the type of data, data length and a basic XOR mask. Longer messages are broken up into multiple frames.
Details at:
This sample websocket implementation here just broadcasts messages from any connected client to all connected clients, like a group chat application.
To use this demo:
- Download pywebsock.py and pywebsock.html
- Run "python pywebsock.py". This starts the server on port 4545.
- Open pywebsock.html with your browser.
- Open pywebsock.html again. Well... to try the message broadcast feature, you would need at least one more browser tab/window with the same html file.
- Type away to send messages from one window and see it appear on other windows.
