FastCGI or SCGI

http://docs.python.org/howto/webservers.html#fastcgi-and-scgi

FastCGI and SCGI try to solve the performance problem of CGI in another way. Instead of embedding the interpreter into the web server, they create long-running background processes. There is still a module in the web server which makes it possible for the web server to “speak” with the background process. As the background process is independent of the server, it can be written in any language, including Python. The language just needs to have a library which handles the communication with the webserver.

The difference between FastCGI and SCGI is very small , as SCGI is essentially just a “simpler FastCGI”. As the web server support for SCGI is limited, most people use FastCGI instead, which works the same way. Almost everything that applies to SCGI also applies to FastCGI as well , so we’ll only cover the latter.

These days, FastCGI is never used directly. Just like mod_python, it is only used for the deployment of WSGI applications.

See also

    * FastCGI, SCGI, and Apache: Background and Future is a discussion on why the concept of FastCGI and SCGI is better that that of mod_python.