Z Handler
This handler allows one to use the Z Object Publisher (formerly Bobo) with
mod_python. This gives you the power of Zope Object Publishing along with the
speed of mod_python. It doesn't get any better than this!
WHAT IS ZPublisher?
ZPublisher is a component of Zope. While I don't profess at Zope itself as it
seems to be designed for different type of users than me, I do think that the
ZPublisher provides an ingeniously simple way of writing WWW applications in
Python.
A quick example do demonstrate the power of ZPublisher.
Suppose you had a file called zhello.py like this:
"""A simple Bobo application"""
def sayHello( name = "World" ):
""" Sais Hello (this comment is required)"""
return "Hello %s!" % name
.Notice it has one method defined in it. Through ZPublisher, that method can be
invoked through the web via a URL similar to this:
http://www.domain.tld/site/zhello/sayHello and
http://www.domain.tld/site/zhello/sayHello?name=Joe
Note how the query keyword "name" converted to a keyword argument to the function.
If the above didn't "click" for you, go read the ZPublisher documentation at
http://classic.zope.org:8080/Documentation/Reference/ObjectPublishingIntro
for a more in-depth explanation.
QUICK START
1. Download and install Zope.
2. Don't start it. You're only interested in ZPublisher, and in order for
it to work, Zope doesn't need to be running.
3. Pick a www directory where you want to use ZPublisher. For our purposes
let's imagine it is accessible via http://www.domain.tld/site.
4. Make sure that the FollowSymLinks option is on for this directory
in httpd.conf.
5. Make a symlink in this directory to the ZPublisher directory:
cd site
ln -s /usr/local/src/Zope-2.1.0-src/lib/python/ZPublisher .
5. Verify that it is correct:
ls -l
lrwxr-xr-x 1 uid group 53 Dec 13 12:15 ZPublisher -> /usr/local/src/Zope-2.1.0-src/lib/python/ZPublisher
6. Create an .htaccess file with this in it:
SetHandler python-program
PythonHandler mod_python.zhandler
PythonDebug
7. Create an above mentioned zhello.py file.
8. Look at http://www.domain.tld/site/zhello/sayHello?name=Joe
Noteworthy:
This module automatically reloads modules just like any other mod_python
module. But modules that are imported by your code will not get reloaded.
There are ways around having to restart the server for script changes to
take effect. For example, let's say you have a module called mycustomlib.py
and you have a module that imports it. If you make a changes to
mycustomlib.py, you can force the changes to take effect by requesting
http://www.domain.tld/site/mycustomlib/. You will get a server error, but
mycustomelib should get reloaded.
P.S.: ZPublisher is not Zope, but only part of it. As of right now, as far
as I know, Zope will not work with mod_python. This is because of locking
issues. Older versions of Zope had no locking, so different children of
apache would corrupt the database by trying to access it at the same time.
Starting with version 2 Zope does have locking, however, it seems that the
first child locks the database without ever releasing it and after that no
other process can access it.
If this is incorrect, and you can manage to get Zope to work without problems,
please send me an e-mail and I will correct this documentation.
Last modified: Fri May 12 22:11:04 EDT 2000