Jeremy, the added detail you have provided caused me to go back and
look
at my code to see if I am doing what you are suggesting. It is not
obvious to me.
I believe I add two things to request.session. One is an update_date
that comes from
a postgresql database and the other is a status text string. Because
the editing session
can cross more than one web page, I wanted to remember the update_date
to ensure
nobody updates my record before I get to update it. I have even gone
and looked at the session database
records, on one occasion, but did not see anything suspicious.
What throws me off, is the pickling error seems to be complaining
about the Session cookie name which
is a datetime that django takes care of - not me.
The code from django.contrib.sessions.middleware.py in the def
SessionMiddleware(object) function
fails on line 89:
response.set_cookie(settings.SESSION_COOKIE_NAME, session_key,
max_age=max_age, expires=expires,
domain=settings.SESSION_COOKIE_DOMAIN)
This is just before it returns response. The line before that creates
a new session:
new_session = Session.objects.save(session_key,
request.session._session,
datetime.datetime.now() +
datetime.timedelta(seconds=settings.SESSION_COOKIE_AGE))
In my code, view.py functions get called every time a webpage is
refreshed or a form gets submitted.
I get my problem without submitting any forms, just scrolling thru
records viewing them, but
this calles the view.py function everytime. As you scroll, the
update_date gets changed
to the one for the next record, from the database. As I am scrolling,
eventually I get this pickling error.
I thought I was using straightforward django technique, except for
using sqlalchemy to access
my database tables.
I am going to look at this further, looking for the scenario you have
outlined. However, I still don't
understand why the code would work fine under certain conditions - ie.
mpm-worker or in the django
development mode.
Mae, you have added a dimension to this for me. Because, I started
experiencing this problem
when I set up a new PC and used the svn to build the software
configuration in site-packages and then
added symbolic links from my svn folder. When I discovered that my
original machine was using the apache2 mpm-worker
and my new target machine was using apache2-prefork, and making it the
same fixed the problem, I thought
the problem was somehow related to apache2.
However, I do not exclude the .pyc files from my svn repository.
Maybe I should. I do notice that sometimes
you have to reload apache2 to get your latest changes. Maybe this is
a characteristic of the prefork apache2 as
it only runs one thread (just guessing).
I appreciate the time you guys are taking to help me with this.
On Apr 5, 12:54 pm, "Jeremy Dunck" <[EMAIL PROTECTED]> wrote:
> On 4/5/07, Mae <[EMAIL PROTECTED]> wrote:
>
>
>
> > Wow, what luck! I've been having a sporadic "" problem, and I've just
> > resigned myself to spending today to try to debug it. Searched the
> > group for exact error, found nothing, refreshed, and saw this post in
> > top slot! Kismet.
>
> (The error is "TypeError: can't pickle function objects", per a later
> email. This error is issued by cPickle rather than pickle, but the
> approach is basically the same.)
>
> In either case, the basic problem is that pickle has to be able to
> re-create the objects later, and can only do that if it knows how to
> refer to the type of the thing it must create. Pickle refuses to
> serialize an object it can't be fairly sure of later de-serializing.
>
> http://docs.python.org/lib/pickle-inst.html
>
> Here's a quick example producing this error:
>
> >>> import cPickle
> >>> def z():
>
> ...: return 1
> ...:
>
> >>> class C(object):
>
> ...: pass
> ...:
>
> >>> c=C()
> >>> cPickle.dumps(c) #works fine
>
> 'ccopy_reg\n_reconstructor\np1\n(c__main__\nC\np2\nc__builtin__\nobject\np3\nNtRp4\n.'
>
> >>> c.x = z
> >>> cPickle.dumps(c) #works fine
>
> "ccopy_reg\n_reconstructor\np1\n(c__main__\nC\np2\nc__builtin__\nobject\np3\nNtRp4\n(dp5\nS'x'\nc__main__\nz\np6\nsb."
>
> >>> def z(): #redefine z, which c.x refers to.
>
> ...: return 2
> ...:
>
> >>> cPickle.dumps(c) #explodes because the function referred to by c.x
>
> no longer has a name.
> ...
> TypeError: can't pickle function objects
>
> --------------------
>
> Similarly, paceman's error is something like this (starting with a new
> interpreter!):
>
> >>> import cPickle
> >>> class C(object):
>
> ...: pass
> ...:
>
> >>> c=C()
> >>> cPickle.dumps(c) #works fine
>
> 'ccopy_reg\n_reconstructor\np1\n(c__main__\nC\np2\nc__builtin__\nobject\np3\nNtRp4\n.'
>
> >>> class C(object): #redefine C
>
> ...: pass
> ...:
>
> >>> cPickle.dumps(c) #fails because the class c is an instance of no
>
> longer has a name.
> ...
> PicklingError: Can't pickle <class '__main__.C'>: it's not the same
> object as __main__.C
>
> -----
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