Configuraion to run pyhton script on ubuntu 12.04

[Jaiky]

Sir i already tried this "Alias" concept

I did the following steps
===============================================================================
Step 1:
added 
"ScriptAlias /cgi-bin/ /var/www/cgi-bin/"

 in   /etc/apache2/sites-available/default
============================================================================

step 2:-

added :-

def main():
    app.run()

if __name__ == '__main__':
    main()

in  /var/www/cgi-bin/hello_world.py


================================================================================
Now my Configuration   of /etc/apache2/sites-available/default in under



<VirtualHost *:80>
        ServerAdmin webmaster at localhost

        DocumentRoot /var/www

        <Directory />
                Options FollowSymLinks
                AllowOverride None
                AddHandler mod_python .py
                PythonHandler mod_python.publisher | .py
                AddHandler mod_python .psp .psp_
                PythonHandler mod_python.psp | .psp .psp
        </Directory>

        ScriptAlias /cgi-bin/ /var/www/cgi-bin/
        <Directory "/var/www/cgi-bin/">
                Options Indexes FollowSymLinks MultiViews ExecCGI
                AllowOverride None
                Order allow,deny
                allow from all
                AddHandler cgi-script cgi pl
        </Directory>

        #ScriptAlias /cgi-bin/ /usr/lib/cgi-bin/
        <Directory "/usr/lib/cgi-bin">
                AllowOverride None
                Options +ExecCGI -MultiViews +SymLinksIfOwnerMatch
                AddHandler cgi-script cgi pl
                Order allow,deny
                Allow from all
        </Directory>

        ErrorLog ${APACHE_LOG_DIR}/error.log

        # Possible values include: debug, info, notice, warn, error, crit,
        # alert, emerg.
        LogLevel warn

        CustomLog ${APACHE_LOG_DIR}/access.log combined
        

     Alias /doc/ "/usr/share/doc/"
    <Directory "/usr/share/doc/">
        Options Indexes MultiViews FollowSymLinks
        AllowOverride None
        Order deny,allow
        Deny from all
        Allow from 127.0.0.0/255.0.0.0 ::1/128
    </Directory>


</VirtualHost>
               

===============================================================================

my code is under /var/www/cgi-bin/hello_world.py




import webapp2

class MainPage(webapp2.RequestHandler):
    def get(self):
       self.response.headers['Content-Type'] = 'text/plain'
       self.response.out.write('Hello, webapp World!')

app = webapp2.WSGIApplication([('/', MainPage)],
                             debug=True)


def main():
    app.run()

if __name__ == '__main__':
    main()
=============================================================================


extra thing i did

in /etc/apache2/mods-available/mod_python.conf
where i created the file "mod_python.conf"



<IfModule mod_python.c>
        AddHandler mod_python .py .psp
        PythonHandler mod_python.publisher | .py
        PythonHandler mod_python.psp | .psp
</IfModule>

################################################################################


when i run localhost/cgi-bin/hello_world.py


error i get 


Not Found

The requested URL /cgi-bin/hello_world.py was not found on this server.
Apache/2.2.22 (Ubuntu) Server at localhost Port 80

#############################################################################