Differences and uses between WSGI, CGI, FastCGI, and mod_python in regards to Python?

Question

I'm just wondering what the differences and advantages are for the different CGI's out there. Which one would be best for python scripts, and how would I tell the script what to use?

Is mod_wsgi faster? My current server uses CGI, what reasons are there to switch? — Parker, Oct 14 '10 at 20:38
Possible duplicate: http://stackoverflow.com/questions/219110/how-python-web-frameworks-wsgi-and-cgi-fit-together — Koroviev, Oct 14 '10 at 20:38
We can't tell you if mod_wsgi will be faster in your environment. You have to actually measure them in your environment with your constraints and your applications and your configuration. — S.Lott, Oct 14 '10 at 21:02
`mod_wsgi` is Apache only. Is it still the most popular in 2012? — anatoly techtonik, Mar 28 '12 at 22:24

score 47 · Accepted Answer · edited May 23 '17 at 11:55

47

A part answer to your question, including scgi.

CGI vs FCGI

Lazy and not writing it on my own. From the wikipedia: http://en.wikipedia.org/wiki/FastCGI

Instead of creating a new process for each request, FastCGI uses persistent processes to handle such requests. Multiple processes can configured, increasing stability and scalability. Each individual FastCGI process can handle many requests over its lifetime, thereby avoiding the overhead of per-request process creation and termination

edited May 23 '17 at 11:55

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answered Oct 14 '10 at 20:24

pyfunc

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There is a FastCGI stdio library (marcos) that let you make a single program capable of running both as CGI and as FastCGI app: http://www.fastcgi.com/devkit/doc/fastcgi-prog-guide/ap_guide.htm – xorcus Mar 30 '14 at 17:57
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Question about FastCGI: How it handle simultaneous connections with one process when PHP itself is blocking language ? What if I have something "sleep(100)" . Wont it block the process for the other users ? Thanks – user345602 Sep 14 '14 at 18:52

score 19 · Answer 2 · edited Jun 22 '18 at 11:27

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There's also a good background reader on CGI, WSGI and other options, in the form of an official python HOWTO: http://docs.python.org/2/howto/webservers.html

edited Jun 22 '18 at 11:27

user703016

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answered Mar 29 '12 at 18:59

Richard Boardman

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This is a great resource for beginners. – GiriB May 18 '17 at 09:50
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Looks like the url is obsolete. But this one works: https://docs.python.org/2/howto/webservers.html – lesnik Feb 05 '18 at 13:58

Cees Timmerman · Answer 3 · 2022-11-09T00:38:06.213

In a project like Django, you can use a WSGI (Web Server Gateway Interface) server from the Flup module.

A WSGI server wraps a back-end process using one or more protocols:

FastCGI (calling a server process)
SCGI (Simple Common Gateway Interface - a simpler FastCGI)
AJP (Apache JServ Protocol - a Java FastCGI)
mod_python (runs pre-loaded code per request - uses lots of RAM)
CGI (Common Gateway Interface, starts a process per request - slow)

In 2019, WSGI was superseded by ASGI (Asynchronous Server Gateway Interface), used by frameworks like FastAPI on servers like Uvicorn, which is much faster.

score 6 · Answer 4 · answered Mar 06 '17 at 11:31

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FastCGI is a kind of CGI which is long-live, which will always be running.
With FastCGI, it'll take less time.
Because of multi-processes, FastCGI will cost more memory than CGI.

In Detail Diff between FastCGI vs CGI

answered Mar 06 '17 at 11:31

naveenKumar

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Differences and uses between WSGI, CGI, FastCGI, and mod_python in regards to Python?

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