Writing Legacy Authentication Backends¶

Authenticates the user against a database or server.

This is responsible for making any necessary communication with the database or server and determining the validity of the credentials passed.

If the credentials are invalid, the function must return None, which will allow it to fall back to the next authentication backend in the chain (or fail, if this is the last authentication backend).

If the credentials are valid, the function must return a valid User. Generally, rather than constructing one itself, it should call its own get_or_create_user() with the username.

To help with debugging, this function should log any errors in communication using Python’s logging support.

The function may need to strip whitespace from the username before authentication. If the server itself strips whitespace when authenticating, but this function does not, it can lead to duplicate users in the database.

Looks up or creates a User based on information from the database or server.

This tends to follow the pattern of:

username = username.strip()

try:
    user = User.objects.get(username=username)
except User.DoesNotExist:
    # Construct a user from the database...
    return user

Like authenticate(), this will look up the user from the database or server. However, it will not verify anything other than the username. It also must make sure to strip the username.

This function is used both when logging in and when adding a user to a review request as a reviewer. In the latter case, Review Board will look up the user using the authentication backend in order to see if the user exists and can be added.

This is a simple function that just looks up the User in the database, given the numeric ID. This should always simply contain:

return get_object_or_none(User, pk=user_id)

Note: get_object_or_none() comes from djblets.util.misc.