We use pickling in conjunction with caches in these cases so we should
be able to fallback to the uncached behavior if the pickled data is
corrupt in some way.
eg. it's a python 2 pickle we don't know how to read.
When going between python 2 and python 3.5 we can get pickeld course
structires that are incompatible no matter what we do do to the bug
linked in the comment. In this case, handle the error and delete the
corrupt data from the cache.
Making this fairly generic because if we have any bad data in cache we
don't want it to blow up the whole process. Just delete the bad data
and try again.
Returning JSON from `login_user` for third party auth failures makes
the response more consistent with all other `login_user` responses.
The only calls to `login_user` with this failure are processed by
`shim_student_view` which will in-turn remove this JSON. This improves
the `login_user` response in advance of switching the logistration page
to use `login_user` without `shim_student_view`.
ARCH-1253
`shim_student_view` is used for login, and is being simplified so it
can ulimately be completely deleted. In this commit, the shim
preprocessing was removed by deleting unused code, and moving code
that is still being used to login_user.
Note: `shim_student_view` was originally added in
https://github.com/edx/edx-platform/pull/5768/files
ARCH-1253
This completes the work started in https://github.com/edx/edx-platform/pull/19453
to use the LMS login and registration for Studio, rather than Studio
providing its own implementation.
LMS login/registration are being used for the following reasons:
1. LMS logistration properly handles all SSO integrations.
2. A single logistration is simpler to maintain and understand.
3. Allows Studio to work more like all other IDAs that use LMS
logistration.
The original switch to use LMS logistration for Studio also added the
toggle `DISABLE_STUDIO_SSO_OVER_LMS` to provide the community some
additional time for switching. This commit removes this toggle, which
at this point means all deployments will use the LMS logistration.
This change requires sharing cookies across LMS and Studio. Should that
prove to be a problem for certain Open edX instances, there are
discussions of possible alternative solutions.
See https://github.com/edx/edx-platform/pull/19845#issuecomment-559154256
Detailed changes:
* Fix some Studio links that still went to old Studio signin and signup.
* Remove DISABLE_STUDIO_SSO_OVER_LMS feature toggle.
* Remove old studio signin and signup pages and templates.
* Fix url name "login", which had different meanings for Studio and LMS.
* Use the following settings: LOGIN_URL, FRONTEND_LOGIN_URL,
FRONTEND_LOGOUT_URL, and FRONTEND_REGISTER_URL.
* Redirect /signin and /signup to the LMS logistration.
* Add custom metric `uses_pattern_library`.
* Add custom metric `student_activate_account`.
* Add Django Settings to allow /signin, /signup, and /login_post to be
disabled once ready.
This work also relates to ARCH-218 and DEPR-6.
ARCH-1253
