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Joel Martin 6a88340929 Refactor and cleanup websocket.py and deps. 
Moved websocket.py code into a class WebSocketServer. WebSockets
server implementations will sub-class and define a handler() method
which is passed the client socket after. Global variable settings have been
changed to be parameters for WebSocketServer when created.

Subclass implementations still have to handle queueing and sending but
the parent class handles everything else (daemonizing, websocket
handshake, encode/decode, etc). It would be better if the parent class
could handle queueing and sending. This adds some buffering and
polling complexity to the parent class but it would be better to do so
at some point. However, the result is still much cleaner as can be
seen in wsecho.py.

Refactored wsproxy.py and wstest.py (formerly ws.py) to use the new
class. Added wsecho.py as a simple echo server.

- rename tests/ws.py to utils/wstest.py and add a symlink from
  tests/wstest.py

- rename tests/ws.html to tests/wstest.html to match utils/wstest.py.

- add utils/wsecho.py

- add tests/wsecho.html which communicates with wsecho.py and simply
  sends periodic messages and shows what is received.
 		2011-01-08 15:29:01 -06:00
..
Makefile wswrapper: interpose select/pselect. Cleaup. 2010-12-27 13:21:07 -07:00
README.md utils/README.md: horizontal looks better. 2011-01-06 19:21:17 -06:00
launch.sh wsproxy.py: add web serving capability. 2011-01-06 18:26:54 -06:00
md5.c Remove left over record code. Squelch compile warnings 2010-11-06 10:53:32 -05:00
md5.h Update C proxy to WS protocol version 76. 2010-06-30 20:39:41 -05:00
md5_test.c Update C proxy to WS protocol version 76. 2010-06-30 20:39:41 -05:00
web.py set socket option SO_REUSEADDR to prevent "Address already in use" error 2010-12-21 23:31:46 +08:00
websocket.c wsproxy: warn when no cert. C sock close cleanup. 2011-01-04 13:14:46 -06:00
websocket.h Add --key option for separate cert and key file. 2010-11-06 10:55:09 -05:00
websocket.py Refactor and cleanup websocket.py and deps. 2011-01-08 15:29:01 -06:00
wsproxy.c wsproxy: warn when no cert. C sock close cleanup. 2011-01-04 13:14:46 -06:00
wsproxy.js wsproxy.js: Fix multi-frame decoding. 2010-11-07 22:28:08 -06:00
wsproxy.py Refactor and cleanup websocket.py and deps. 2011-01-08 15:29:01 -06:00
wstest.py Refactor and cleanup websocket.py and deps. 2011-01-08 15:29:01 -06:00
wswrap wswrapper: fix preload path and interpose port. 2010-12-16 14:04:16 -06:00
wswrapper.c wswrapper: update README, DO_MSG def for output. 2010-12-29 14:11:28 -07:00
wswrapper.h wswrapper: update README, DO_MSG def for output. 2010-12-29 14:11:28 -07:00

README.md

WebSockets Utilities: wswrapper and wsproxy

wswrapper

wswrapper is an LD_PRELOAD library that converts a TCP listen socket of an existing program to a be a WebSockets socket. The wswrap script can be used to easily launch a program using wswrapper. Here is an example of using wswrapper with vncserver. wswrapper will convert the socket listening on port 5901 to be a WebSockets port:

`cd noVNC/utils`

`./wswrap 5901 vncserver -geometry 640x480 :1`

wsproxy

At the most basic level, wsproxy just translates WebSockets traffic to normal socket traffic. wsproxy accepts the WebSockets handshake, parses it, and then begins forwarding traffic between the client and the target in both directions. WebSockets payload data is UTF-8 encoded so in order to transport binary data it must use an encoding that can be encapsulated within UTF-8. wsproxy uses base64 to encode all traffic to and from the client. Also, WebSockets traffic starts with '\0' (0) and ends with '\xff' (255). Some buffering is done in case the data from the client is not a full WebSockets frame (i.e. does not end in 255).

Additional wsproxy features

These are not necessary for the basic operation.

  • Daemonizing: When the -f option is not specified, wsproxy runs in the background as a daemon process.

  • SSL (the wss:// WebSockets URI): This is detected automatically by wsproxy by sniffing the first byte sent from the client and then wrapping the socket if the data starts with '\x16' or '\x80' (indicating SSL).

  • Flash security policy: wsproxy detects flash security policy requests (again by sniffing the first packet) and answers with an appropriate flash security policy response (and then closes the port). This means no separate flash security policy server is needed for supporting the flash WebSockets fallback emulator.

  • Session recording: This feature that allows recording of the traffic sent and received from the client to a file using the --record option.

Implementations of wsproxy

There are three implementations of wsproxy: python, C, and Node (node.js). wswrapper is only implemented in C.

Here is the feature support matrix for the the wsproxy implementations and wswrapper:

Program Language Proxy or Interposer Multiprocess Daemonize SSL/wss Flash Policy Server Session Record Web Server
wsproxy.py python proxy yes yes yes 1 yes yes yes
wsproxy C proxy yes yes yes yes no no
wsproxy.js Node (node.js) proxy yes no no no no no
wswrap/wswrapper.so shell/C interposer indirectly indirectly no no no no
  • Note 1: to use SSL/wss with python 2.5 or older, see the following section on Building the Python ssl module.

Building the Python ssl module (for python 2.5 and older)

  • Install the build dependencies. On Ubuntu use this command:

    sudo aptitude install python-dev bluetooth-dev

  • Download, build the ssl module and symlink to it:

    cd noVNC/utils

    wget http://pypi.python.org/packages/source/s/ssl/ssl-1.15.tar.gz

    tar xvzf ssl-1.15.tar.gz

    cd ssl-1.15

    make

    cd ../

    ln -sf ssl-1.15/build/lib.linux-*/ssl ssl