feat: add first batch of Open edX Filters

* Add PreEnrollmentFilter
* Add PreRegisterFilter
* Add PreLoginFilter

For more info: openedx/edx-platform#29449

Some events that were already on the platform were also added:
* Add COURSE_ENROLLMENT_CHANGED: sent after the enrollment update
* Add COURSE_ENROLLMENT_CREATED event after the user's enrollment creation
* Add COURSE_UNENROLLMENT_COMPLETED: sent after the user's unenrollment

For more info:
openedx/edx-platform#28266
openedx/edx-platform#28640

Author: mariajgrimaldi

common/djangoapps/student/models.py

@@ -55,6 +55,18 @@
 from slumber.exceptions import HttpClientError, HttpServerError
 from user_util import user_util
 
+from openedx_events.learning.data import (
+    CourseData,
+    CourseEnrollmentData,
+    UserData,
+    UserPersonalData,
+)
+from openedx_events.learning.signals import (
+    COURSE_ENROLLMENT_CHANGED,
+    COURSE_ENROLLMENT_CREATED,
+    COURSE_UNENROLLMENT_COMPLETED,
+)
+from openedx_filters.learning.filters import CourseEnrollmentStarted
 import openedx.core.djangoapps.django_comment_common.comment_client as cc
 from common.djangoapps.course_modes.models import CourseMode, get_cosmetic_verified_display_price
 from common.djangoapps.student.emails import send_proctoring_requirements_email
@@ -1100,6 +1112,10 @@ class AlreadyEnrolledError(CourseEnrollmentException):
     pass
 
 
+class EnrollmentNotAllowed(CourseEnrollmentException):
+    pass
+
+
 class CourseEnrollmentManager(models.Manager):
     """
     Custom manager for CourseEnrollment with Table-level filter methods.
@@ -1555,6 +1571,13 @@ def enroll(cls, user, course_key, mode=None, check_access=False, can_upgrade=Fal
 
         Also emits relevant events for analytics purposes.
         """
+        try:
+            user, course_key, mode = CourseEnrollmentStarted.run_filter(
+                user=user, course_key=course_key, mode=mode,
+            )
+        except CourseEnrollmentStarted.PreventEnrollment as exc:
+            raise EnrollmentNotAllowed(str(exc)) from exc
+
         if mode is None:
             mode = _default_course_mode(str(course_key))
         # All the server-side checks for whether a user is allowed to enroll.

common/djangoapps/student/tests/test_filters.py

@@ -0,0 +1,104 @@
+"""
+Test that various filters are fired for models in the student app.
+"""
+from django.test import override_settings
+from xmodule.modulestore.tests.django_utils import ModuleStoreTestCase
+from xmodule.modulestore.tests.factories import CourseFactory
+from openedx_filters.learning.filters import CourseEnrollmentStarted
+from openedx_filters import PipelineStep
+
+from common.djangoapps.student.models import CourseEnrollment, EnrollmentNotAllowed
+from common.djangoapps.student.tests.factories import UserFactory, UserProfileFactory
+from openedx.core.djangolib.testing.utils import skip_unless_lms
+
+
+class TestEnrollmentPipelineStep(PipelineStep):
+    """
+    Utility function used when getting steps for pipeline.
+    """
+
+    def run_filter(self, user, course_key, mode):  # pylint: disable=arguments-differ
+        """Pipeline steps that changes mode to honor."""
+        if mode == "no-id-professional":
+            raise CourseEnrollmentStarted.PreventEnrollment()
+        return {"mode": "honor"}
+
+
+@skip_unless_lms
+class EnrollmentFiltersTest(ModuleStoreTestCase):
+    """
+    Tests for the Open edX Filters associated with the enrollment process through the enroll method.
+
+    This class guarantees that the following filters are triggered during the user's enrollment:
+
+    - CourseEnrollmentStarted
+    """
+
+    def setUp(self):  # pylint: disable=arguments-differ
+        super().setUp()
+        self.course = CourseFactory.create()
+        self.user = UserFactory.create(
+            username="test",
+            email="[email protected]",
+            password="password",
+        )
+        self.user_profile = UserProfileFactory.create(user=self.user, name="Test Example")
+
+    @override_settings(
+        OPEN_EDX_FILTERS_CONFIG={
+            "org.openedx.learning.course.enrollment.started.v1": {
+                "pipeline": [
+                    "common.djangoapps.student.tests.test_filters.TestEnrollmentPipelineStep",
+                ],
+                "fail_silently": False,
+            },
+        },
+    )
+    def test_enrollment_filter_executed(self):
+        """
+        Test whether the student enrollment filter is triggered before the user's
+        enrollment process.
+
+        Expected result:
+            - CourseEnrollmentStarted is triggered and executes TestEnrollmentPipelineStep.
+            - The arguments that the receiver gets are the arguments used by the filter
+            with the enrollment mode changed.
+        """
+        enrollment = CourseEnrollment.enroll(self.user, self.course.id, mode='audit')
+
+        self.assertEqual('honor', enrollment.mode)
+
+    @override_settings(
+        OPEN_EDX_FILTERS_CONFIG={
+            "org.openedx.learning.course.enrollment.started.v1": {
+                "pipeline": [
+                    "common.djangoapps.student.tests.test_filters.TestEnrollmentPipelineStep",
+                ],
+                "fail_silently": False,
+            },
+        },
+    )
+    def test_enrollment_filter_prevent_enroll(self):
+        """
+        Test prevent the user's enrollment through a pipeline step.
+
+        Expected result:
+            - CourseEnrollmentStarted is triggered and executes TestEnrollmentPipelineStep.
+            - The user can't enroll.
+        """
+        with self.assertRaises(EnrollmentNotAllowed):
+            CourseEnrollment.enroll(self.user, self.course.id, mode='no-id-professional')
+
+    @override_settings(OPEN_EDX_FILTERS_CONFIG={})
+    def test_enrollment_without_filter_configuration(self):
+        """
+        Test usual enrollment process, without filter's intervention.
+
+        Expected result:
+            - CourseEnrollmentStarted does not have any effect on the enrollment process.
+            - The enrollment process ends successfully.
+        """
+        enrollment = CourseEnrollment.enroll(self.user, self.course.id, mode='audit')
+
+        self.assertEqual('audit', enrollment.mode)
+        self.assertTrue(CourseEnrollment.is_enrolled(self.user, self.course.id))

openedx/core/djangoapps/user_authn/views/login.py

@@ -28,6 +28,11 @@
 from ratelimit.decorators import ratelimit
 from rest_framework.views import APIView
 
+from openedx_events.learning.data import UserData, UserPersonalData
+from openedx_events.learning.signals import SESSION_LOGIN_COMPLETED
+from openedx_filters.learning.filters import StudentLoginRequested
+
+from common.djangoapps import third_party_auth
 from common.djangoapps.edxmako.shortcuts import render_to_response
 from openedx.core.djangoapps.password_policy import compliance as password_policy_compliance
 from openedx.core.djangoapps.site_configuration import helpers as configuration_helpers
@@ -500,6 +505,13 @@ def login_user(request):
 
         possibly_authenticated_user = user
 
+        try:
+            possibly_authenticated_user = StudentLoginRequested.run_filter(user=possibly_authenticated_user)
+        except StudentLoginRequested.PreventLogin as exc:
+            raise AuthFailedError(
+                str(exc), redirect_url=exc.redirect_to, error_code=exc.error_code, context=exc.context,
+            ) from exc
+
         if not is_user_third_party_authenticated:
             possibly_authenticated_user = _authenticate_first_party(request, user, third_party_auth_requested)
             if possibly_authenticated_user and password_policy_compliance.should_enforce_compliance_on_login():

openedx/core/djangoapps/user_authn/views/register.py

@@ -23,6 +23,9 @@
 from django.views.decorators.debug import sensitive_post_parameters
 from edx_django_utils.monitoring import set_custom_attribute
 from edx_toggles.toggles import LegacyWaffleFlag, LegacyWaffleFlagNamespace
+from openedx_events.learning.data import UserData, UserPersonalData
+from openedx_events.learning.signals import STUDENT_REGISTRATION_COMPLETED
+from openedx_filters.learning.filters import StudentRegistrationRequested
 from pytz import UTC
 from ratelimit.decorators import ratelimit
 from requests import HTTPError
@@ -522,6 +525,14 @@ def post(self, request):
         data = request.POST.copy()
         self._handle_terms_of_service(data)
 
+        try:
+            data = StudentRegistrationRequested.run_filter(form_data=data)
+        except StudentRegistrationRequested.PreventRegistration as exc:
+            errors = {
+                "error_message": [{"user_message": str(exc)}],
+            }
+            return self._create_response(request, errors, status_code=exc.status_code)
+
         response = self._handle_duplicate_email_username(request, data)
         if response:
             return response