It could be completely unrelated to the User data model - if they are storing any other serialized objects in the session which have had their structure updated between v15 and v17, then when the session object gets deserialized from the datastore/memcache, it will also have the same symptoms.
The suggested fixes would still resolve the issue as well. Cheers, Simon On Friday, 12 April 2013 18:56:32 UTC+1, Vinny P wrote: > > Hello Jun, > > A jsessionid cookie simply stores a hash, it cannot by itself cause a > crash. > > What's happening is that the hash is taken from the cookie, and used to > look up the Entity representing the user in the memcache/datastore. You > probably changed the user data model between v15 and v17, so when the user > data is pulled out of the datastore, App Engine is unable to deserialize > into the model that it's expecting, and errors out. > > What I would do is add an additional entry to your Users model, listing > the version of the application that the User entity was created under. Then > do an equality test when the user hits your application: If the user's data > model and the current application code are identical (ie v15/v15 or > v17/v17), then everything's OK. Let the user pass. If the data model was > created under v15 and the current application is v17, delete the cookie, > delete the user entity, and kick the user out to a login page. > > Second way: Rewrite your home page to be entirely static; just a .html > file, not a .jsp or servlet (this prevents AppEngine from processing > anything, since instances don't handle static assets). Insert Javascript > code to access and delete all cookies (you can do this via > document.cookie). Users will have to click to another page to login. > > Third way: Change your user data model to be identical under v15 and v17. > (Also known as the less fun way.) > > ----------------- > -Vinny P > Technology & Media Advisor > Chicago, IL > > @GOV on AppDotNet: https://alpha.app.net/gov > > > On Friday, April 12, 2013 10:45:45 AM UTC-5, Jun Ho Huh wrote: >> >> >> Hi all, >> >> We are having trouble transitioning from an old version of the code (v15) >> to a newer version (v17). If a user is logged in (we use our own User >> model, not one provided by GAE) to v15, and when we make v17 the default >> version, the logged in user gets Internal Server 500 error when they try to >> access our website. If the user is not logged in, then this issue does not >> exist when we transit to v17. >> >> We noticed that the issue has something to do with the jsessionid cookie >> which gets created and updated when user logs into our website. We know >> this because if we delete this cookie (when a user is logged in) and change >> it to v17, the error 500 doesn't appear. So something is crashing >> internally when it tries to bring back the session information from the old >> cookie that was created through v15. And this problem disappears when the >> user is logged out: so the problem only exists for users who are logged in >> through v15 (so when they come back they go straight to the logged in >> state) and gets exposed to v17 while the session cookie captures their >> logged in state. >> >> It's a hard problem to solve (and we've been spending weeks on this) >> because nothing gets logged on GAE admin console, and we couldn't reproduce >> the problem in localhost (i.e., switching back and forth between different >> versions that we get from our SVN server). There's no information that is >> useful for us to see what might be causing this to happen, and this issue >> is stopping us from going to the updated version of the website. >> >> Has anyone ever encountered this kind of problem, and figured out >> workarounds? >> >> Any kind of help would be much appreciated. >> >> >> Thanks! >> > -- You received this message because you are subscribed to the Google Groups "Google App Engine" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send email to [email protected]. Visit this group at http://groups.google.com/group/google-appengine?hl=en. For more options, visit https://groups.google.com/groups/opt_out.
