## noVNC: HTML5 VNC Client
### Description
noVNC is a VNC client implemented using HTML5 technologies,
specifically Canvas and WebSocket (supports 'wss://' encryption).
For browsers that do not have builtin WebSocket support, the project
includes [web-socket-js](http://github.com/gimite/web-socket-js),
a WebSocket emulator using Adobe Flash .
In addition, [as3crypto](http://github.com/lyokato/as3crypto_patched)
has been added to web-socket-js to implement WebSocket SSL/TLS
encryption, i.e. the "wss://" URI scheme.
Running in Chrome before and after connecting:
### 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'). One advantage of using the proxy is that it has
builtin support for SSL/TLS encryption (i.e. "wss://").
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.
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
* To encrypt the traffic using the WebSocket 'wss://' URI scheme you
need to generate a certificate for the proxy to load. You can generate
a self-signed certificate using openssl. The common name should be the
hostname of the server where the proxy will be running:
`openssl req -new -x509 -days 365 -nodes -out self.pem -keyout self.pem`
* run a VNC server.
`vncserver :1`
* run the python proxy:
`./utils/wsproxy.py -f source_port target_addr:target_port
`./utils/wsproxy.py -f 8787 localhost:5901`
* run the mini python web server to serve the directory:
`./utils/web.py PORT`
`./utils/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!
### Browser Support
In the following table Jaunty is Ubuntu 9.04 and WinXP is Windows XP.
#### Linux (Ubuntu 9.04)
OS | Browser | Status | Notes |
---|---|---|---|
Jaunty | Chrome 5.0.375.29 | Excellent | Very fast. Native WebSockets. |
Jaunty | Firefox 3.5 | Good | Large full-color images are somewhat slow from web-socket-js overhead. |
Jaunty | Opera 10.60 | Poor | web-socket-js problems, mouse/keyboard issues. See note 1 |
Jaunty | Arora 0.5 | Good | Broken putImageData so large full-color images are slow. Uses web-socket-js. |
Jaunty | Konqueror 4.2.2 | Broken | web-socket-js never loads |
WinXP | Chrome 5.0.375.99 | Excellent | Very fast. Native WebSockets. |
WinXP | Firefox 3.0.19 | Good | Some overhead from web-socket-js. |
WinXP | Safari 5.0 | Fair | Fast. Native WebSockets. Broken 'wss://' (SSL) - weird client header |
WinXP | IE 6, 7, 8 | Non-starter | No basic Canvas support. Javascript painfully slow. |