Re: [Demexp-dev] Web Client Source Available

[David MENTRE]

Hello,

David MENTRE <address@hidden> writes:

> Last minute update: there is apparently an issue when trying to reach a
> question's details: in works fine with a localhost URL but not with the
> above one. I don't know why and moreover the issue seems transient. :-(

I tried to investigate this issue.

Here is the error I get:

"""
Mod_python error: "PythonHandler mod_python.publisher"

Traceback (most recent call last):

  File "/usr/lib/python2.5/site-packages/mod_python/apache.py", line 299, in 
HandlerDispatch
    result = object(req)

  File "/usr/lib/python2.5/site-packages/mod_python/publisher.py", line 213, in 
handler
    published = publish_object(req, object)

  File "/usr/lib/python2.5/site-packages/mod_python/publisher.py", line 412, in 
publish_object
    return publish_object(req,util.apply_fs_data(object, req.form, req=req))

  File "/usr/lib/python2.5/site-packages/mod_python/util.py", line 439, in 
apply_fs_data
    return object(**args)

  File "/var/www/lyu-proto/python/login.py", line 472, in consult_question
    tag_list = question_tags[qu_id]['tag_set']

NameError: global name 'question_tags' is not defined
"""

As far as I have understood, when looking at a question details the
function "consult_question()" is called. This function uses the global
variable "question_tags" which, at this time, is undefined. This
variable is defined in function "login()". For some reason, this
definition is lost when going from the list of question (calling
"login()") to the question details (calling "consult_question()").

I suspect this is due to the fact we can have several Python
interpreters, each one handling a request. For example, the first Python
interpreter could handle the "login()" while a second one the call to
"consult_question()". That would explain why the variable is undefined
in the second function. I'm using Apache2 in MPM (Multi-Processing
Module) prefork mode, which could creates multiple interpreters (one per
forked apache2 process). But all this is a wild guess, I've not been
able to find a way to verify if all of this is true or not.

Anyway, a way to fix the bug would be to check that the variable
"question_tags" does exist and, if this not the case, create it by
calling an appropriate function. I haven't done it yet.

Yours,
d.
-- 
GPG/PGP key: A3AD7A2A David MENTRE <address@hidden>
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