Websockets

2013 - New way for javascript to open a tcp connection back to the server for data transfer.

Here is some notes as I struggled to get the first examples to work.

Errors in apache log files
1. Exception: ('PythonOption mod_pywebsocket.handler_root is not defined', 3)
2. AttributeError: object has no attribute "APLOG_DEBUG"
Cause was that i had to have the websocket config above the default virtual server in my apache2 config file.

##PES 2013 pywebsocket
<IfModule python_module>
  PythonPath "sys.path+['/mod_pywebsocket']"
  PythonOption mod_pywebsocket.handler_root /var/www
  PythonOption mod_pywebsocket.handler_scan /var/www/ws
  #PythonOption mod_pywebsocket.allow_draft75 On
  <Location /ws>
    PythonHeaderParserHandler mod_pywebsocket.headerparserhandler
  </Location>
</IfModule>  

<VirtualHost *:80>

        ServerAdmin webmaster@localhost

        DocumentRoot /var/www
        <Directory />
                Options FollowSymLinks
                AllowOverride None
        </Directory>
        <Directory /var/www/>
                Options Indexes FollowSymLinks MultiViews
                AllowOverride None
                Order allow,deny
                allow from all
        </Directory>
        ErrorLog ${APACHE_LOG_DIR}/error.log
        LogLevel debug
        CustomLog ${APACHE_LOG_DIR}/access.log combined
</VirtualHost>

To test
1. copy file echo_wsh.py into /var/www/ws
2. open webpage to test file:///usr/share/doc/python-mod-pywebsocket/examples/console.html in browser
3. test by entering in webpage abe the url ws://localhost/ws/echo
4. on web page in display window you should see message Connect ws://localhost/ws/echo
Another problem was with /var/www/ws/websockify_wsh.py
- Found in Apache2 log websockify: ws_protocol = 'binary' (['binary', 'base64'])
- It was picking binary for socket and noVNC only supports base64.
  - Solution, just before it picked the first option, i check for base64 and rather select it.
Another problem, connecting with vnc.html, found in apache2 log.
- mod_pywebsocket: websockify: connection denied: 'NoneType' object has no attribute 'split'

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CategoryDevelopement