Code review comments

common/djangoapps/util/authentication.py

@@ -0,0 +1,48 @@
+""" Common Authentication Handlers used across projects. """
+from rest_framework import authentication
+
+
+class SessionAuthenticationAllowInactiveUser(authentication.SessionAuthentication):
+    """Ensure that the user is logged in, but do not require the account to be active.
+
+    We use this in the special case that a user has created an account,
+    but has not yet activated it.  We still want to allow the user to
+    enroll in courses, so we remove the usual restriction
+    on session authentication that requires an active account.
+
+    You should use this authentication class ONLY for end-points that
+    it's safe for an un-activated user to access.  For example,
+    we can allow a user to update his/her own enrollments without
+    activating an account.
+
+    """
+    def authenticate(self, request):
+        """Authenticate the user, requiring a logged-in account and CSRF.
+
+        This is exactly the same as the `SessionAuthentication` implementation,
+        with the `user.is_active` check removed.
+
+        Args:
+            request (HttpRequest)
+
+        Returns:
+            Tuple of `(user, token)`
+
+        Raises:
+            PermissionDenied: The CSRF token check failed.
+
+        """
+        # Get the underlying HttpRequest object
+        request = request._request  # pylint: disable=protected-access
+        user = getattr(request, 'user', None)
+
+        # Unauthenticated, CSRF validation not required
+        # This is where regular `SessionAuthentication` checks that the user is active.
+        # We have removed that check in this implementation.
+        if not user:
+            return None
+
+        self.enforce_csrf(request)
+
+        # CSRF passed with authenticated user
+        return (user, None)