HOWTO Use Python in the web — Python v3.0.1 documentation

HOWTO Use
Python in the web — Python v3.0.1 documentation

mod_python?

People coming from PHP often find it hard to grasp how to use Python
in the web. Their first thought is mostly mod_python because they think that
this is the equivalent to mod_php. Actually it is not really. It does
embed the interpreter into the Apache process, thus speeding up requests
by not having to start a Python interpreter every request. On the other
hand, it is by far not “Python intermixed with HTML” as PHP often does.
The Python equivalent of that is a template engine. mod_python itself is
much more powerful and gives more access to Apache internals. It can
emulate CGI, it can work an a “Python Server Pages” mode similar to JSP
which is “HTML intermangled with Python” and it has a “Publisher” which
destignates one file to accept all requests and decide on what to do
then.

But mod_python has some problems. Unlike the PHP interpreter the
Python interpreter uses caching when executing files, so when changing a
file the whole web server needs to be re-started to update. Another
problem ist the basic concept – Apache starts some child processes to
handle the requests and unfortunately every child process needs to load
the whole Python interpreter even if it does not use it. This makes the
whole web server slower. Another problem is that as mod_python is linked
against a specific version of libpython,
it is not possible to switch from an older version to a newer (e.g. 2.4
to 2.5) without recompiling mod_python. mod_python is also bound to the
Apache web server, so programs written for mod_python cannot easily run
on other web servers.

These are the reasons why mod_python should be avoided when writing
new programs. In some circumstances it might be still a good idea to use
mod_python for deployment, but WSGI makes it possible to run WSGI
programs under mod_python as well.

HOWTO Use Python in the web — Python v3.0.1
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