Major Description
From mailing list.
ImportError: cannot import name publisher
------------------------------------
In a directory publisher, setup for mod_python.publisher as described in
previous email, and with same index.py. Ie.,
import os
def index():
return os.getpid(),_file_
Now create a parallel directory called "handler" and in its .htaccess file add:
SetHandler python-program
PythonHandler mptest
PythonDebug On
The mptest.py file in that directory should read:
from mod_python import apache
import os
from mod_python import publisher
def handler(req):
req.content_type = "text/plain"
req.send_http_header()
req.write(str((os.getpid(),_file_)))
return apache.OK
Restart Apache to clear caches and access "handler" and "publisher"
directories in that order. One gets:
(747, '/Users/grahamd/Sites/handler/mptest.py')
(747, '/Users/grahamd/Sites/publisher/index.py')
(747, '/Users/grahamd/Sites/handler/mptest.py')
(747, '/Users/grahamd/Sites/publisher/index.py')
Okay, everything is fine.
Now restart Apache to clear caches and access "publisher" and then
"handler". Ie., in reverse order. One gets:
(761, '/Users/grahamd/Sites/publisher/index.py')
Mod_python error: "PythonHandler mptest"
Traceback (most recent call last):
File "/System/Library/Frameworks/Python.framework/Versions/2.3/lib/python2.3/site-packages/mod_python/apache.py", line 296, in HandlerDispatch
log=debug)
File "/System/Library/Frameworks/Python.framework/Versions/2.3/lib/python2.3/site-packages/mod_python/apache.py", line 421, in import_module
autoreload=autoreload,log=log,path=path)
File "/System/Library/Frameworks/Python.framework/Versions/2.3/lib/python2.3/site-packages/mod_python/apache.py", line 474, in _unsafe_import_module
module = imp.load_module(mname, f, p, d)
File "/Users/grahamd/Sites/handler/mptest.py", line 4, in ?
from mod_python import publisher
ImportError: cannot import name publisher
The way in which mod_python.publisher is loaded as PythonHandler,
if done before being imported explicitly using "import", screws up
that latter import.
I know some will scream that I am mixing "import" and "import_module()",
but since mod_python.publisher is installed into "site-packages", one
should expect it to work with "import". Whether it does is order dependent.
Because I use mod_python.publisher in Vampire for its user authentication
stuff, this problem means that if using Vampire and elsewhere also wanting
to use mod_python.publisher as PythonHandler, that the Vampire area
should be setup with its own PythonInterpreter instance.
Having now remembered this problem, as a workaround in Vampire I
should probably go and use:
publisher = apache.import_module("mod_python.publisher")
instead. At least that way it will work all the time. 
I know my wanting to use internals of mod_python.publisher is the
exception, but these sort of strange things shouldn't by right happen.