CAS 3.0 support

[fmyzjs]

CAS 3.0 support

To support CAS 3.0,the attribute mapper should be like:
@carsongee

def populate_user(user, authentication_response):
    if authentication_response is not None:
        if authentication_response.has_key('is_superuser'):
            user.is_superuser = authentication_response['is_superuser']

        if authentication_response.has_key('is_staff'):
            user.is_staff = authentication_response['is_staff']

        if authentication_response.has_key('givenName'):
            user.first_name = authentication_response['givenName']

        if authentication_response.has_key('sn'):
            user.last_name = authentication_response['sn']

        if authentication_response.has_key('email'):
            user.email = authentication_response['email']

    pass

[carsongee]

Can you add a unit test for this? Also, do you know how you can determine if the response you get passed in is protocol version 2 or 3? Since they give very different attribute dictionaries, it would be nice to either add something to both of them, or at least know how to differentiate i.e.

if authentication_response is not None:
   if authentication_response.has_key('sn'):
       # Protocol 3.0 logic
   elif authentication_response.find(CAS + 'authenticationSuccess/'  + CAS + 'attributes'  , namespaces=NSMAP):
        # Protocol 2.0 attribute handler

[fmyzjs]

What about this
set CAS_VERSION on aws.py

if CAS_VERSION=='3':
      pass

[carsongee]

Well, you won't necessarily know the version in the client at configuration time. i.e. I upgrade my CAS from Jasig 3.5 to 4.x then the attribute mapper would fail. In the worst case, I think my code example above would work as an example, and I could update our reference version to have that. The more I think about it, that is probably the only way to do it and maintain backwards compatibility with the current attribute mapper's out there.

[fmyzjs]

.CAS_VERSION was 2 on init.py .if people try to use cas 3 ,must set var CAS_VERSION on configuration first.

[carsongee]

I totally missed that in init, and that it came from configuration already. Sorry about that. I just verified that there aren't issues with this in our current setup, so it looks good. I would just really like a unit test for it since I can't really verify myself without setting up a CAS 3.0 server. We will also need to have https://github.com/edx/edx-platform/pull/6127 merge before I merge this.

[pdpinch]

@carsongee what do you think we should do with this and mitocw/mitx_cas_mapper#1

[carsongee]

I think it would be nice if we wrote tests and validated that this works with a CAS 3.0 server as it would be valuable to the edx community. A better option may be switching the platform to using https://github.com/mingchen/django-cas-ng as it is a much better maintained fork, though they only test down to Django 1.5, so it may not work with our 1.4 installation