Installing Python with mod_wsgi on OS X Snow Leopard's default Apache

Most of the instructions here can be found elsewhere on the Internet, but I couldn’t find a comprehensive step-by-step guide that covered everything needed. So, here goes; this should cover everything you need to do to get going with Python, when starting with a stock OS X Snow Leopard Apache:

• Download mod_wsgi from http://code.google.com/p/modwsgi/wiki/DownloadTheSoftware?tm=2, and save it to your Desktop.
• Untar the archive, and install mod_wsgi:

  # cd ~/Desktop
  # tar xvfz mod_wsgi-3.3.tar.gz
  # cd mod_wsgi-3.3
  # ./configure
  # make
  # sudo make install

• Then, edit your Apache main configuration file:

  # cd /etc/apache2
  # sudo nano httpd.conf

  Add the following line after the other LoadModule lines:

  LoadModule wsgi_module libexec/apache2/mod_wsgi.so

• Go back to the directory where you untarred the mod_wsgi source:

  # cd ~/Desktop/mod_wsgi-3.3
  # make clean

• Create new directories outside your webroot for storing the script files, and to be used as a separate webroot for python apps:

  # cd ~
  # mkdir wsgi_source
  # mkdir wsgi_web

• Save a test script in the new wsgi_source directory as test.wsgi:

  def application(environ, start_response):
      status = '200 OK'
      output = 'Hello World!'
      response_headers = [('Content-type', 'text/plain'),
                          ('Content-Length', str(len(output)))]
      start_response(status, response_headers)
      return [output]

• Create a new virtual host for your Python applications. Add this to your /etc/apache2/users/YOURUSERNAME.conf :

  <VirtualHost *:80>
      ServerName localpython
  
      DocumentRoot /Users/YOURUSERNAME/wsgi_web
  
      <Directory /Users/YOURUSERNAME/wsgi_web>
      Order allow,deny
      Allow from all
      </Directory>
  
      WSGIScriptAlias /myapp /Users/YOURUSERNAME/wsgi_source/test.wsgi
  
      <Directory /Users/YOURUSERNAME/wsgi_source>
      Order allow,deny
      Allow from all
      </Directory>
  </VirtualHost>

• Add this to your /etc/hosts:

  127.0.0.1 localpython

• Restart Apache:

  # sudo apachectl restart

• Go to http://localpython/myapp , and you should see your “hello world”. If you don’t, something has gone wrong. The easiest way to start debugging is to check your Apache error logs at /var/log/apache2/error_log
  

More instructions can be found on the mod_wsgi site.