[ http://issues.apache.org/jira/browse/MODPYTHON-112?page=all ]
Graham Dumpleton updated MODPYTHON-112:
---------------------------------------
Attachment: grahamd_20060223_1.diff
Attached patch "grahamd_20060223_1.diff".
Would like confirmation on final solution for this issue before I commit
changes.
Behaviour would be such that req.phase is always set to be the phase of the
currently executing handler. If an input or output filter is triggered it will
no longer overwrite the value of req.phase. Thus, if in the content handler,
req.phase will stay as "PythonHandler" for the whole time the handler is
executing.
If there is no mod_python content handler and just a mod_python input or output
filter, accessing filter.req.phase from the filter will result in the Python
None value. This will be the case even if a prior phase to the content handler
executed as a mod_python handler, eg. "PythonFixupHandler", as req.phase will
be cleared at the end of any mod_python handler phase.
That is, at no time will req.phase be set to be either PythonInputFilter or
PythonOutputFilter like it used to. Whether a filter is running in input or
output mode is determinable from filter.is_input so no need for filter
directive name to be put in req.phase. This does not cause any problems for
CallBack.FilterDispatch() in apache.py as it didn't use req.phase, but used
filter.is_input where necessary. The change to CallBack.HandlerDispatch() in
apache.py to cache the phase the handler is executing in as described
previously for this issue, is no longer necessary with the way this fix works.
> If using filters value of req.phase only valid up till first
> req.read()/req.write().
> ------------------------------------------------------------------------------------
>
> Key: MODPYTHON-112
> URL: http://issues.apache.org/jira/browse/MODPYTHON-112
> Project: mod_python
> Type: Bug
> Components: core
> Versions: 3.1.4, 3.2
> Reporter: Graham Dumpleton
> Attachments: grahamd_20060223_1.diff
>
> The request object provides a member variable called 'phase' described as:
> The phase currently being being processed, e.g. "PythonHandler". (Read-Only)
> If no Python based input and output filters are used, the value of req.phase
> will be constant for the life of a request phase. If however you use an input
> or output filter, the value of req.phase can change.
> Consider that we are in the content handler phase and where there is a Python
> based output filter, but no Python based input filter. On initially entering
> the request handler, the value of req.phase will be "PythonHandler". As soon
> as req.write() is called however, the value of req.phase changes to
> "PythonOutputFilter".
> Now, if there is a Python based input filter, but no Python based output
> filter, the value of req.phase will change to "PythonInputFilter" as soon as
> req.read() is called.
> If there are both Python based input and output filters, the value of
> req.phase will in turn change to "PythonInputFilter" and "PythonOutputFilter"
> as req.read() and then req.write() are in turn called.
> The reason for all this is that in the get_request_object() function of
> src/mod_python.c, it contains code:
> /* make a note of which phase we are in right now */
> Py_XDECREF(request_obj->phase);
> if (phase)
> request_obj->phase = PyString_FromString(phase);
> else
> request_obj->phase = PyString_FromString("");
> That is, whenever called to get the request object, it will update req.phase.
> This will occur even if the request object had already been created, as will
> be the case when there is a Python based content handler and either a Python
> based input or output filter.
> Overall this behaviour is a bit strange and unexpected. It would seem to me
> that it if there is both a handler and a filter, that the value of req.phase
> would be left as the name of the handler phase. Ie., it would stay for
> example as "PythonHandler" and not be changed to "PythonInputFilter" or
> "PythonOutFilter".
> One can't just change the code in get_request_object() not to update it if
> already set, as it has to be updated when one moves from one phase to
> another. One has to contend with where this function is called in
> python_filter() function, namely:
> /* create/acquire request object */
> request_obj = get_request_object(req, interp_name,
>
> is_input?"PythonInputFilter":"PythonOutputFilter");
> First step may be simply not to pass in "PythonInputFilter" or
> "PythonOutputFilter" and instead just call it as:
> request_obj = get_request_object(req, interp_name,0);
> At the same time change get_request_object() to:
> Py_XDECREF(request_obj->phase);
> if (phase)
> request_obj->phase = PyString_FromString(phase);
> else if (!request_obj->phase)
> request_obj->phase = PyString_FromString("");
> Ie., result will be that if req.phase is set, leave it alone when called by
> python_filter() with phase set 0. If req.phase isn't already set, set it to
> the empty string.
> The consequences of this are that if there are filters but no Python based
> handlers, then req.phase will get set to an empty string in that case.
> Another strange case is that if the only Python based handler was for an
> early phase than what is consuming or generating the content to be processed,
> then req.phase will be set to a value corresponding to that earlier phase and
> not where the current action is. For example, if there was an AccessHandler
> but then content came from a static file, output filter would see
> "AccessHandler".
> Thus, whatever is done, there will be some strangeness. Thus, question
> remains of what should be done, or if it should be left that way and that
> documentation changed to say that req.phase is only valid up until first call
> to req.read() or req.write() within a handler.
> This is not an ideal situation though as a handler may want to interogate
> req.phase after req.read() or req.write() has been called for some reason,
> which would yield incorrect results if a filter is being used. An example of
> where this occurs is in error reporting in the HandlerDispatch of
> mod_python.apache itself. When it is generating an error message, the phase
> shown in the error message will be wrong if there was a filter. It should
> perhaps at least be changed to save away req.phase at start of dispatch so it
> knows it is correct later for any error messages.
> Any comments?????
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