603500 - Replace Django's @permission_required

Status: VERIFIED FIXED

(support.mozilla.org :: Code Quality, task, P3)

Description

[James Socol [:jsocol, :james]]

The built-in @permission_required decorator in Django has an annoying behavior of always sending users to the login page, even if they're already logged in. This is confusing and leads to false-positive bug reports about session issues.

A while ago I wrote a replacement decorator for another project, it's designed to act as a drop-in replacement: http://gist.github.com/592040, except that it only redirects to the login page if users are not authenticated, and returns a normal HttpResponseForbidden if they are.

Pros: more accurate user experience.
Cons: it's copied and forked from Django, so we have to maintain it ourselves. Also I would need to write a test or two specifically for it.

Thoughts? Is it worth it?

Comment 1

[James Socol [:jsocol, :james]]

The more I think about this the more necessary it will be, assuming the log in view in 2.4 does what I imagine it will do: redirect you automatically if you're already logged in. In that case, imagine user Bob visits /foo, and doesn't have permissions to view it. He's redirected to /login, which, because he's already authenticated, redirects him back to /foo, which redirects him back to /login, ad infinitum.

Comment 2

[James Socol [:jsocol, :james]]

Per discussion, we'll make the switch. I'll start with the linked decorator and tweak it to work with our setup, and include tests.

Comment 3

[James Socol [:jsocol, :james]]

http://github.com/jsocol/kitsune/commit/5a947024e5

For clarity and posterity:

While navigating to a URL requiring permission, let's say /flagged

If you:                            You will see:
are logged out                     a redirect to the login page.
are logged in without permission   an error.
are logged in with permission      the page.

Comment 4

[Rebecca Billings [:rbillings]]

Verified all three states