VNC HTML5 Client

Description

A VNC client implemented using HTML5, specifically Canvas and WebSocket.

For browsers that do not have builtin WebSocket support, the project includes web-socket-js, a WebSocket emulator using Adobe Flash (http://github.com/gimite/web-socket-js).

Requirements

Until there is VNC server support for WebSocket connections, you need to use a WebSocket to TCP socket proxy. There is a python proxy included ('wsproxy').

There a few reasons why a proxy is required:

1. WebSocket is not a pure socket protocol. There is an initial HTTP like handshake to allow easy hand-off by web servers and allow some origin policy exchange. Also, each WebSocket frame begins with 0 ('\x00') and ends with 255 ('\xff').

2. Javascript itself does not have the ability to handle pure byte strings (Unicode encoding messes with it) even though you can read them with WebSocket. The python proxy encodes the data so that the Javascript client can base64 decode the data into an array. The client requests this encoding

3. When using the web-socket-js as a fallback, WebSocket 'onmessage' events may arrive out of order. In order to compensate for this the client asks the proxy (using the initial query string) to add sequence numbers to each packet.

Usage

• run a VNC server.

  vncserver :1

• run the python proxy:

  ./wsproxy.py [listen_port] [vnc_host] [vnc_port]

  ./wsproxy.py 8787 localhost 5901

• run the mini python web server to serve the directory:

  ./web.py PORT

  ./web.py 8080

• Point your web browser at http://localhost:8080/vnc.html (or whatever port you used above to run the web server).

• Specify the host and port where the proxy is running and the password that the vnc server is using (if any). Hit the Connect button and enjoy!