Specially handle login redirect for mobile apps

lms/envs/common.py

@@ -2706,3 +2706,8 @@ MAX_BOOKMARKS_PER_COURSE = 100
 # lms.env.json file.
 
 REGISTRATION_EXTENSION_FORM = None
+
+# Identifier included in the User Agent from open edX mobile apps.
+MOBILE_APP_USER_AGENT_REGEXES = [
+    r'edX/org.edx.mobile',
+]

openedx/core/djangoapps/safe_sessions/middleware.py

@@ -61,10 +61,12 @@ from django.contrib.auth import SESSION_KEY
 from django.contrib.auth.views import redirect_to_login
 from django.contrib.sessions.middleware import SessionMiddleware
 from django.core import signing
+from django.http import HttpResponse
 from django.utils.crypto import get_random_string
 from hashlib import sha256
 from logging import getLogger
 
+from openedx.core.lib.mobile_utils import is_request_from_mobile_app
 
 log = getLogger(__name__)
 
@@ -339,6 +341,12 @@ class SafeSessionMiddleware(SessionMiddleware):
         cookie and redirects the user to the login page.
         """
         _mark_cookie_for_deletion(request)
+
+        # Mobile apps have custom handling of authentication failures. They
+        # should *not* be redirected to the website's login page.
+        if is_request_from_mobile_app(request):
+            return HttpResponse(status=401)
+
         return redirect_to_login(request.path)
 
     @staticmethod

openedx/core/djangoapps/safe_sessions/tests/test_middleware.py

@@ -10,6 +10,7 @@ from django.contrib.auth.models import AnonymousUser
 from django.http import HttpResponse, HttpResponseRedirect, SimpleCookie
 from django.test import TestCase
 from django.test.client import RequestFactory
+from django.test.utils import override_settings
 from mock import patch
 
 from student.tests.factories import UserFactory
@@ -18,6 +19,17 @@ from ..middleware import SafeSessionMiddleware, SafeCookieData
 from .test_utils import TestSafeSessionsLogMixin
 
 
+def create_mock_request():
+    """
+    Creates and returns a mock request object for testing.
+    """
+    request = RequestFactory()
+    request.COOKIES = {}
+    request.META = {}
+    request.path = '/'
+    return request
+
+
 class TestSafeSessionProcessRequest(TestSafeSessionsLogMixin, TestCase):
     """
     Test class for SafeSessionMiddleware.process_request
@@ -25,9 +37,7 @@ class TestSafeSessionProcessRequest(TestSafeSessionsLogMixin, TestCase):
     def setUp(self):
         super(TestSafeSessionProcessRequest, self).setUp()
         self.user = UserFactory.create()
-        self.request = RequestFactory()
-        self.request.COOKIES = {}
-        self.request.path = '/'
+        self.request = create_mock_request()
 
     def assert_response(self, safe_cookie_data=None, success=True):
         """
@@ -128,9 +138,7 @@ class TestSafeSessionProcessResponse(TestSafeSessionsLogMixin, TestCase):
     def setUp(self):
         super(TestSafeSessionProcessResponse, self).setUp()
         self.user = UserFactory.create()
-        self.request = RequestFactory()
-        self.request.COOKIES = {}
-        self.request.path = '/'
+        self.request = create_mock_request()
         self.request.session = {}
         self.client.response = HttpResponse()
         self.client.response.cookies = SimpleCookie()
@@ -230,9 +238,7 @@ class TestSafeSessionMiddleware(TestSafeSessionsLogMixin, TestCase):
     def setUp(self):
         super(TestSafeSessionMiddleware, self).setUp()
         self.user = UserFactory.create()
-        self.request = RequestFactory()
-        self.request.COOKIES = {}
-        self.request.path = '/'
+        self.request = create_mock_request()
         self.client.response = HttpResponse()
         self.client.response.cookies = SimpleCookie()
 
@@ -246,7 +252,10 @@ class TestSafeSessionMiddleware(TestSafeSessionsLogMixin, TestCase):
                 settings.SESSION_COOKIE_NAME
             ]
 
-    def test_success(self):
+    def verify_success(self):
+        """
+        Verifies success path.
+        """
         self.client.login(username=self.user.username, password='test')
         self.request.user = self.user
 
@@ -265,11 +274,27 @@ class TestSafeSessionMiddleware(TestSafeSessionsLogMixin, TestCase):
             response = SafeSessionMiddleware().process_response(self.request, self.client.response)
         self.assertEquals(response.status_code, 200)
 
-    def test_error(self):
+    def test_success(self):
+        self.verify_success()
+
+    def test_success_from_mobile_web_view(self):
+        self.request.path = '/xblock/block-v1:org+course+run+type@html+block@block_id'
+        self.verify_success()
+
+    @override_settings(MOBILE_APP_USER_AGENT_REGEXES=[r'open edX Mobile App'])
+    def test_success_from_mobile_app(self):
+        self.request.META = {'HTTP_USER_AGENT': 'open edX Mobile App Version 2.1'}
+        self.verify_success()
+
+    def verify_error(self, expected_response_status):
+        """
+        Verifies error path.
+        """
         self.request.COOKIES[settings.SESSION_COOKIE_NAME] = 'not-a-safe-cookie'
 
         with self.assert_parse_error():
-            SafeSessionMiddleware().process_request(self.request)
+            request_response = SafeSessionMiddleware().process_request(self.request)
+            self.assertEquals(request_response.status_code, expected_response_status)
 
         self.assertTrue(self.request.need_to_delete_cookie)
         self.cookies_from_request_to_response()
@@ -277,3 +302,15 @@ class TestSafeSessionMiddleware(TestSafeSessionsLogMixin, TestCase):
         with patch('django.http.HttpResponse.set_cookie') as mock_delete_cookie:
             SafeSessionMiddleware().process_response(self.request, self.client.response)
             self.assertTrue(mock_delete_cookie.called)
+
+    def test_error(self):
+        self.verify_error(302)
+
+    def test_error_from_mobile_web_view(self):
+        self.request.path = '/xblock/block-v1:org+course+run+type@html+block@block_id'
+        self.verify_error(401)
+
+    @override_settings(MOBILE_APP_USER_AGENT_REGEXES=[r'open edX Mobile App'])
+    def test_error_from_mobile_app(self):
+        self.request.META = {'HTTP_USER_AGENT': 'open edX Mobile App Version 2.1'}
+        self.verify_error(401)

openedx/core/lib/mobile_utils.py

+"""
+Common utilities related to the mobile apps.
+"""
+
+import re
+from django.conf import settings
+
+
+def is_request_from_mobile_app(request):
+    """
+    Returns whether the given request was made by an open edX mobile app,
+    either natively or through the mobile web view.
+
+    Note: The check for the user agent works only for mobile apps version 2.1
+    and higher.  Previous apps did not update their user agents to include the
+    distinguishing string.
+
+    The check for the web view is a temporary check that works for mobile apps
+    version 2.0 and higher.  See is_request_from_mobile_web_view for more
+    information.
+
+    Args:
+        request (HttpRequest)
+    """
+    if is_request_from_mobile_web_view(request):
+        return True
+
+    if getattr(settings, 'MOBILE_APP_USER_AGENT_REGEXES', None):
+        user_agent = request.META.get('HTTP_USER_AGENT')
+        if user_agent:
+            for user_agent_regex in settings.MOBILE_APP_USER_AGENT_REGEXES:
+                if re.match(user_agent_regex, user_agent):
+                    return True
+
+    return False
+
+
+PATHS_ACCESSED_BY_MOBILE_WITH_SESSION_COOKIES = [
+    r'^/xblock/{usage_key_string}$'.format(usage_key_string=settings.USAGE_KEY_PATTERN),
+]
+
+
+def is_request_from_mobile_web_view(request):
+    """
+    Returns whether the given request was made by an open edX mobile web
+    view using a session cookie.
+
+    Args:
+        request (HttpRequest)
+    """
+
+    # TODO (MA-1825): This is a TEMPORARY HACK until all of the version 2.0
+    # iOS mobile apps have updated.  The earlier versions didn't update their
+    # user agents so we are checking for the specific URLs that are
+    # accessed through the mobile web view.
+    for mobile_path in PATHS_ACCESSED_BY_MOBILE_WITH_SESSION_COOKIES:
+        if re.match(mobile_path, request.path):
+            return True
+
+    return False