How can I understand which page user is looking for, if they should be defined in the url like:
http://mysite.appspot.com/something/something-else/ - this is page1
http://mysite.appspot.com/something/something-else/page1 - page1 also
http://mysite.appspot.com/something/something-else/page2 - page2
http://mysite.appspot.com/something/something-else/pageN - pageN
Can I define that with WSGIApplication / app.yaml?
Assuming that you want to use the same handler regardless of page, you can treat part of the path as your page variable.
app.yaml: