Session use outside of <Directory> directive.

• Key: MODPYTHON-50
• Type: Improvement
• Status: Closed
• Resolution: Fixed
• Priority: Minor
• Assignee: Nicolas Lehuen
• Reporter: Graham Dumpleton
• Component/s: core
• Affects Version/s: 3.1.4
• Fix Version/s: 3.2.7

Description

MODPYTHON-31 was previously closed with outcome of "Won't Fix".
The orginal problem as described in the report was actually not connected
to the Python traceback which was supplied, but the Python traceback
still identified a problem which shold be fixed. Have logged this separate
report to cover this issue.

The issue again came up recently on the mailing list as:

  http://www.modpython.org/pipermail/mod_python/2005-April/017933.html

Specifically, if PythonHandler is specified outside of any <Directory>
directive and sessions are used, you can get the error:

Mod_python error: "PythonHandler mod_python.psp"

Traceback (most recent call last):

  File "/usr/lib/python2.3/site-packages/mod_python/apache.py", line 299, in
HandlerDispatch
    result = object(req)

  File "/usr/lib/python2.3/site-packages/mod_python/psp.py", line 297, in
handler
    p.run()

  File "/usr/lib/python2.3/site-packages/mod_python/psp.py", line 191, in run
    session = Session.Session(req)

  File "/usr/lib/python2.3/site-packages/mod_python/Session.py", line 389, in
Session
    timeout=timeout, lock=lock)

  File "/usr/lib/python2.3/site-packages/mod_python/Session.py", line 294, in
__init__
    timeout=timeout, lock=lock)

  File "/usr/lib/python2.3/site-packages/mod_python/Session.py", line 132, in
__init__
    Cookie.add_cookie(self._req, self.make_cookie())

  File "/usr/lib/python2.3/site-packages/mod_python/Session.py", line 160, in
make_cookie
    c.path = dirpath[len(docroot):]

TypeError: unsubscriptable object

This is ultimately caused by code in BaseSession.make_cookie() which reads:

    def make_cookie(self):

        if self._secret:
            c = Cookie.SignedCookie(COOKIE_NAME, self._sid,
                                    secret=self._secret)
        else:
            c = Cookie.Cookie(COOKIE_NAME, self._sid)

        config = self._req.get_options()
        if config.has_key("ApplicationPath"):
            c.path = config["ApplicationPath"]
        else:
            docroot = self._req.document_root()
            # the path where *Handler directive was specified
            dirpath = self._req.hlist.directory
            c.path = dirpath[len(docroot):]

            # Sometimes there is no path, e.g. when Location
            # is used. When Alias or UserDir are used, then
            # the path wouldn't match the URI. In those cases
            # just default to '/'
            if not c.path or not self._req.uri.startswith(c.path):
                c.path = '/'

        return c

What happens when PythonHandler is defined outside of a <Directory>
directive is that req.hlist.directory is None, thus indexing into dirpath
fails.

A workaround is to set ApplicationPath option, but true fix would be
to write code something like:

            # the path where *Handler directive was specified
            dirpath = self._req.hlist.directory
            if dirpath:
                docroot = self._req.document_root()
                c.path = dirpath[len(docroot):]
            else:
                c.path ='/'

            # Sometimes there is no path, e.g. when Location
            # is used. When Alias or UserDir are used, then
            # the path wouldn't match the URI. In those cases
            # just default to '/'
            if not c.path or not self._req.uri.startswith(c.path):
                c.path = '/'

This would eliminate the problem altogether and avoid user having to
use workaround of setting ApplicationPath option.

Comments

[Nicolas Lehuen]

Fixed as suggested by Graham.