Pass information between requests webapp2
You can do it in many ways.

Set cookie by first response and it will be passed to next request - unsafe even cookie is crypted but can be.
First GET will send author to second POST page - POST will send author (hidden field).
First GET will send author to POST url as param (same as above).
You will create session id and save in datastore and with author, GET will send session id cookie, PUT will send session id and you will read from datastore session id with author.
You can use memcache as datastore but it is dangerous (it can be flushed and data is not persistent in cache by design).
You can pass session id from GET to POST with use hidden field not cookie or url.

Consider the simples is GET and redirect to valid POST with variable in URL or in hidden field - other methods is more complex but it need chain of GET/POST.
Is it possible to pass information between requests with webapp2?
I have a class that has to set the author variable on HTTP GET. The HTTP POST will check if author exists, and then continue posting. I tried by having a global variable author=None and then setting author in the HTTP GET, but I think the object is destroyed when the HTTP POST request is made to the same controller.
Any help would be great, thanks!