We were already using signals for everything except delete, and even
in our old version of django the delete signal exists (it didn't exist
when this code was first written).
Django doesn't really like models to be OOP like this, so keeping PgModel
would cause issues with upcoming changes in django 1.8. Using simple functions
is easier, and the actual functionality is replicated straight off.
It should have been done through the model, but that is somehow not working.
Therefor, make an immediate purge of the results to the specific survey that
is being voted on.
Most of these forms look pretty benign, but the user profile form, which
includes an SSH key field, certainly needs to be protected.
The survey form is unprotected because it's served over insecure HTTP
and the Varnish proxy strips cookies, which is required by the builtin
CSRF protection.
Marti Raudsepp
This allows all models inherited from PgModel to specify which
URLs to purge by either setting a field or defining a function
called purge_urls, at which point they will be purged whenever
the save signal is fired.
Also implements a form under /admin/purge/ that allows for manual
purging. This should probably be extended in the future to show
the status of the pgq slaves, but that will come later.
Includes a SQL function that posts the expires to a pgq queue. For
a local deployment, this can be replaced with a simple void function
to turn off varnish purging.
Each module now contains a struct.py file that will return all
the URLs that it can generate (yes, this is a small break of the
abstraction of url.py, but we've broken that elsewhere as well),
and also which search-engine-weight (0.1-1.0) that this URL should
be given.
