librelist archives

Re: [flask] Flask session error

From:

Rob Pfeifer

Date:

2012-01-20 @ 08:34

Thanks Daniel. I guess I'm confused as I've commented out everything I was
saving to session and the only thing left in is a "logged_in" variable.
Also, the error only pops up after the 2nd or 3rd call of the view. I'm
just not sure what would be in the session that can't be pickled

Thanks, Rob

2012/1/19 Daniel Neuhäuser <dasdasich@googlemail.com>

> You have something in the session that can't be pickled.
>
> Am 20.01.2012 um 08:31 schrieb Rob Pfeifer <rob.pfeifer@gmail.com>:
>
>
> I've been trying to figure out what's causing this error, but can't figure
> it out for the life of me. ANy ideas of things to check? I can include a
> code snippet if that would help
>
> https://gist.github.com/1645986
>
>
>  [error] [client 67.188.136.142] mod_wsgi (pid=17166): Exception occurred
> processing WSGI script '/srv/www/examenu.com/examenu.wsgi'., referer:
> http://examenu.com/
> [Thu Jan 19 23:21:34 2012] [error] [client 67.188.136.142] Traceback (most
> recent call last):, referer: http://examenu.com/
> [Thu Jan 19 23:21:34 2012] [error] [client 67.188.136.142]   File
> "/usr/lib/python2.7/dist-packages/flask/app.py", line 1306, in __call__,
> referer: http[Thu Jan 19 23:21:34 2012] [error] [client 67.188.136.142]
> mod_wsgi (pid=17166): Exception occurred processing WSGI script '/srv/www/
> examenu.com/examenu.wsgi'., referer: http://examenu.com/
> [Thu Jan 19 23:21:34 2012] [error] [client 67.188.136.142] Traceback (most
> recent call last):, referer: http://examenu.com/
> [Thu Jan 19 23:21:34 2012] [error] [client 67.188.136.142]   File
> "/usr/lib/python2.7/dist-packages/flask/app.py", line 1306, in __call__,
> referer: http://examenu.com/
> [Thu Jan 19 23:21:34 2012] [error] [client 67.188.136.142]     return
> self.wsgi_app(environ, start_response), referer: http://examenu.com/
> [Thu Jan 19 23:21:34 2012] [error] [client 67.188.136.142]   File
> "/usr/lib/python2.7/dist-packages/flask/app.py", line 1294, in wsgi_app,
> referer: http://examenu.com/
> [Thu Jan 19 23:21:34 2012] [error] [client 67.188.136.142]     response =
> self.make_response(self.handle_exception(e)), referer: http://examenu.com/
> [Thu Jan 19 23:21:34 2012] [error] [client 67.188.136.142]   File
> "/usr/lib/python2.7/dist-packages/flask/app.py", line 1292, in wsgi_app,
> referer: http://examenu.com/
> [Thu Jan 19 23:21:34 2012] [error] [client 67.188.136.142]     response =
> self.full_dispatch_request(), referer: http://examenu.com/
> [Thu Jan 19 23:21:34 2012] [error] [client 67.188.136.142]   File
> "/usr/lib/python2.7/dist-packages/flask/app.py", line 1064, in
> full_dispatch_request, referer: http://examenu.com/
> [Thu Jan 19 23:21:34 2012] [error] [client 67.188.136.142]     response =
> self.process_response(response), referer: http://examenu.com/
> [Thu Jan 19 23:21:34 2012] [error] [client 67.188.136.142]   File
> "/usr/lib/python2.7/dist-packages/flask/app.py", line 1188, in
> process_response, referer: http://examenu.com/
> [Thu Jan 19 23:21:34 2012] [error] [client 67.188.136.142]
> self.save_session(ctx.session, response), referer: http://examenu.com/
> [Thu Jan 19 23:21:34 2012] [error] [client 67.188.136.142]   File
> "/usr/lib/python2.7/dist-packages/flask/app.py", line 608, in save_session,
> referer: http://examenu.com/
> [Thu Jan 19 23:21:34 2012] [error] [client 67.188.136.142]
> expires=expires, httponly=True, domain=domain), referer:
> http://examenu.com/
> [Thu Jan 19 23:21:34 2012] [error] [client 67.188.136.142]   File
> "/usr/lib/pymodules/python2.7/werkzeug/contrib/securecookie.py", line 325,
> in save_cookie, referer: http://examenu.com/
> [Thu Jan 19 23:21:34 2012] [error] [client 67.188.136.142]     data =
> self.serialize(session_expires or expires), referer: http://examenu.com/
> [Thu Jan 19 23:21:34 2012] [error] [client 67.188.136.142]   File
> "/usr/lib/pymodules/python2.7/werkzeug/contrib/securecookie.py", line 231,
> in serialize, referer: http://examenu.com/
> [Thu Jan 19 23:21:34 2012] [error] [client 67.188.136.142]
> self.quote(value), referer: http://examenu.com/
> [Thu Jan 19 23:21:34 2012] [error] [client 67.188.136.142]   File
> "/usr/lib/pymodules/python2.7/werkzeug/contrib/securecookie.py", line 188,
> in quote, referer: http://examenu.com/
> [Thu Jan 19 23:21:34 2012] [error] [client 67.188.136.142]     value =
> cls.serialization_method.dumps(value), referer: http://examenu.com/
> [Thu Jan 19 23:21:34 2012] [error] [client 67.188.136.142]   File
> "/usr/lib/python2.7/copy_reg.py", line 77, in _reduce_ex, referer:
> http://examenu.com/
> [Thu Jan 19 23:21:34 2012] [error] [client 67.188.136.142]     raise
> TypeError("a class that defines __slots__ without ", referer:
> http://examenu.com/
> [Thu Jan 19 23:21:34 2012] [error] [client 67.188.136.142] TypeError: a
> class that defines __slots__ without defining __getstate__ cannot be
> pickled, referer: http://examenu.com/
>
>

Le 20/01/2012 09:34, Rob Pfeifer a écrit :
> Thanks Daniel. I guess I'm confused as I've commented out everything I
> was saving to session and the only thing left in is a "logged_in"
> variable. Also, the error only pops up after the 2nd or 3rd call of the
> view. I'm just not sure what would be in the session that can't be pickled
>

> File  "/usr/lib/pymodules/python2.7/werkzeug/contrib/securecookie.py",
> line 188, in quote
>     value = cls.serialization_method.dumps(value)

Hi,

Run your application in the development server in debug mode 
(app.run(debug=True)), reproduce the exception, click on the frame 
quoted above, and run "print value" in the inline terminal.

This will show you what the un-picklable value is, which is hopefully a 
clue to where it is coming from.

Regards,
-- 
Simon Sapin