[ http://issues.apache.org/jira/brows...237
4689 ]

Graham Dumpleton commented on MODPYTHON-161:
--------------------------------------------

FWIW, problems can also arise with PythonInterpPerDirectory. In this case th
e issue is that the interpreter name in that case is derived from the value 
of req.filename at the time the handler is called. The same issues as above 
can therefore arise in that
req.filename could be given a value that doesn't have a trailing slash or wh
ich uses Win32 forward slashes instead of backslashes. This could therefore 
mean a different interpreter to that which was expected might be used for a 
subsequent handler phase i
f req.filename was modified.


> Wrong interpreter chosen with req.add_handler()/PythonInterpPerDirective.
> -------------------------------------------------------------------------
>
>          Key: MODPYTHON-161
>          URL: http://issues.apache.org/jira/browse/MODPYTHON-161
>      Project: mod_python
>         Type: Bug

>   Components: core
>     Versions: 3.3
>     Reporter: Graham Dumpleton

>
> Having fixed MODPYTHON-160, if using:
> # .htaccess
> SetHandler mod_python
> PythonInterpPerDirective On
> PythonFixupHandler interpreter_1
> # interpreter_1.py
> from mod_python import apache
> import os, sys
> directory = os.path.dirname(__file__)
> def fixuphandler(req):
>     req.log_error("fixuphandler")
>     req.log_error("interpreter=%s"%req.interpreter)
>     req.log_error("directory=%s"%req.hlist.directory)
>     req.add_handler("PythonHandler","interpreter_1",directory)
>     return apache.OK
> def handler(req):
>     req.log_error("handler")
>     req.log_error("interpreter=%s"%req.interpreter)
>     req.log_error("directory=%s"%req.hlist.directory)
>     req.content_type = 'text/plain'
>     req.write('hello')
>     return apache.OK
> when select_interp_name() in src/mod_python.c tries to determine the interpreter n
ame, for PythonInterPerDirective, it will use the value as supplied as directory arg
ument to req.add_handler(). In doing this though, it doesn't consider the fact that 
the
directory may not have a trailing slash and since interpreter names for PythonInterpPerDirec
tive always have a trailing slash, the handler will not be executed in correct interpreter c
ontext.
> [Sun Apr 16 17:20:00 2006] [notice] mod_python: (Re)importing modu
le 'interpreter_1'
> [Sun Apr 16 17:20:00 2006] [error] [client ::1] fixuphandler
> [Sun Apr 16 17:20:00 2006] [error] [client ::1] interpreter=/U
sers/grahamd/Workspaces/testing/interpreter-1/
> [Sun Apr 16 17:20:00 2006] [error] [client ::1] directory=/Use
rs/grahamd/Workspaces/testing/interpreter-1/
> [Sun Apr 16 17:20:00 2006] [notice] mod_python: (Re)importing modu
le 'interpreter_1'
> [Sun Apr 16 17:20:00 2006] [error] [client ::1] handler
> [Sun Apr 16 17:20:00 2006] [error] [client ::1] interpreter=/U
sers/grahamd/Workspaces/testing/interpreter-1
> [Sun Apr 16 17:20:00 2006] [error] [client ::1] directory=/Use
rs/grahamd/Workspaces/testing/interpreter-1
> A further problem is that normally the path indicating where a directive was defin
ed is internally calculated from Apache configuration and thus always uses POSIX dir
ectory conventions, ie., forward slash. If the above code were run on Win32, the dir
ect
ory calculated from __file__ is going to most likely use DOS directory conve
ntions, ie., backward slash. Thus, even if a trailing slash were to be added
, it still will not work because the remainder of the path is going to use b
ackward slash and thus the
interpreter name still will not match what it probably should be.
> The main purpose of the directory argument to req.add_handler() is to know where t
o find the module referenced in the handler argument. In this case it is also used t
o determine the Python interpreter name. The fix may be that the interpreter name be
 de
termined in some other way based on the interpreter in use when the req.add_handler() call w
as made.
> This is just part of problems I can possibly see with calculation of interpreter n
ames for handlers. More on this another time. :-)

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