Merge pull request #17 from edx/clintonb/jwt

Added JWT Authentication

course_discovery/apps/api/jwt_decode_handler.py

+"""
+Custom JWT decoding function for django_rest_framework jwt package.
+
+Adds logging to facilitate debugging of InvalidTokenErrors.  Also
+requires "exp" and "iat" claims to be present - the base package
+doesn't expose settings to enforce this.
+"""
+import logging
+
+import jwt
+from rest_framework_jwt.settings import api_settings
+
+logger = logging.getLogger(__name__)
+
+
+def decode(token):
+    """
+    Ensure InvalidTokenErrors are logged for diagnostic purposes, before
+    failing authentication.
+
+    Args:
+        token (str): JSON web token (JWT) to be decoded.
+    """
+
+    options = {
+        'verify_exp': api_settings.JWT_VERIFY_EXPIRATION,
+        'require_exp': True,
+        'require_iat': True,
+    }
+
+    try:
+        return jwt.decode(
+            token,
+            api_settings.JWT_SECRET_KEY,
+            api_settings.JWT_VERIFY,
+            options=options,
+            leeway=api_settings.JWT_LEEWAY,
+            audience=api_settings.JWT_AUDIENCE,
+            issuer=api_settings.JWT_ISSUER,
+            algorithms=[api_settings.JWT_ALGORITHM]
+        )
+    except jwt.InvalidTokenError:
+        logger.exception('JWT decode failed!')
+        raise

course_discovery/apps/api/v1/tests/test_views.py

 # pylint: disable=redefined-builtin
 import json
 import urllib
+from time import time
 
 import ddt
+import jwt
+from django.conf import settings
 from rest_framework.reverse import reverse
 from rest_framework.test import APITestCase, APIRequestFactory
 
@@ -59,6 +62,23 @@ class CatalogViewSetTests(ElasticsearchTestMixin, SerializationMixin, APITestCas
         self.course = CourseFactory(id='a/b/c', name='ABC Test Course')
         self.refresh_index()
 
+    def generate_jwt_token_header(self, user):
+        """Generate a valid JWT token header for authenticated requests."""
+        now = int(time())
+        ttl = 5
+        payload = {
+            'iss': settings.JWT_AUTH['JWT_ISSUER'],
+            'aud': settings.JWT_AUTH['JWT_AUDIENCE'],
+            'username': user.username,
+            'email': user.email,
+            'iat': now,
+            'exp': now + ttl
+        }
+
+        token = jwt.encode(payload, settings.JWT_AUTH['JWT_SECRET_KEY']).decode('utf-8')
+
+        return 'JWT {token}'.format(token=token)
+
     def test_create_without_authentication(self):
         """ Verify authentication is required when creating, updating, or deleting a catalog. """
         self.client.logout()
@@ -77,8 +97,7 @@ class CatalogViewSetTests(ElasticsearchTestMixin, SerializationMixin, APITestCas
         response = getattr(self.client, http_method)(url, {}, format='json')
         self.assertEqual(response.status_code, 403)
 
-    def test_create(self):
-        """ Verify the endpoint creates a new catalog. """
+    def assert_catalog_created(self, **headers):
         name = 'The Kitchen Sink'
         query = '*.*'
         data = {
@@ -86,7 +105,7 @@ class CatalogViewSetTests(ElasticsearchTestMixin, SerializationMixin, APITestCas
             'query': query
         }
 
-        response = self.client.post(reverse('api:v1:catalog-list'), data, format='json')
+        response = self.client.post(reverse('api:v1:catalog-list'), data, format='json', **headers)
         self.assertEqual(response.status_code, 201)
 
         catalog = Catalog.objects.latest()
@@ -94,6 +113,15 @@ class CatalogViewSetTests(ElasticsearchTestMixin, SerializationMixin, APITestCas
         self.assertEqual(catalog.name, name)
         self.assertEqual(catalog.query, query)
 
+    def test_create_with_session_authentication(self):
+        """ Verify the endpoint creates a new catalog when the client is authenticated via session authentication. """
+        self.assert_catalog_created()
+
+    def test_create_with_jwt_authentication(self):
+        """ Verify the endpoint creates a new catalog when the client is authenticated via JWT authentication. """
+        self.client.logout()
+        self.assert_catalog_created(HTTP_AUTHORIZATION=self.generate_jwt_token_header(self.user))
+
     def test_courses(self):
         """ Verify the endpoint returns the list of courses contained in the catalog. """
         url = reverse('api:v1:catalog-courses', kwargs={'id': self.catalog.id})

course_discovery/apps/api/v1/views.py

@@ -6,6 +6,7 @@ from rest_framework.authentication import SessionAuthentication
 from rest_framework.decorators import detail_route
 from rest_framework.permissions import DjangoModelPermissionsOrAnonReadOnly, IsAuthenticatedOrReadOnly
 from rest_framework.response import Response
+from rest_framework_jwt.authentication import JSONWebTokenAuthentication
 
 from course_discovery.apps.api.pagination import ElasticsearchLimitOffsetPagination
 from course_discovery.apps.api.serializers import CatalogSerializer, CourseSerializer, ContainedCoursesSerializer
@@ -20,8 +21,7 @@ logger = logging.getLogger(__name__)
 class CatalogViewSet(viewsets.ModelViewSet):
     """ Catalog resource. """
 
-    # TODO Add support for JWT
-    authentication_classes = (SessionAuthentication,)
+    authentication_classes = (SessionAuthentication, JSONWebTokenAuthentication,)
     permission_classes = (DjangoModelPermissionsOrAnonReadOnly,)
     lookup_field = 'id'
     queryset = Catalog.objects.all()
@@ -95,7 +95,7 @@ class CatalogViewSet(viewsets.ModelViewSet):
 
 class CourseViewSet(viewsets.ReadOnlyModelViewSet):
     """ Course resource. """
-    authentication_classes = (SessionAuthentication,)
+    authentication_classes = (SessionAuthentication, JSONWebTokenAuthentication,)
     lookup_field = 'id'
     lookup_value_regex = COURSE_ID_REGEX
     permission_classes = (IsAuthenticatedOrReadOnly,)

course_discovery/apps/core/tests/factories.py

@@ -6,6 +6,7 @@ USER_PASSWORD = 'password'
 
 
 class UserFactory(factory.DjangoModelFactory):
+    username = factory.Sequence(lambda n: 'user_%d' % n)
     password = factory.PostGenerationMethodCall('set_password', USER_PASSWORD)
     is_active = True
     is_superuser = False

course_discovery/settings/base.py

@@ -243,6 +243,15 @@ REST_FRAMEWORK = {
     )
 }
 
+# NOTE (CCB): JWT_SECRET_KEY is intentionally not set here to avoid production releases with a public value.
+# Set a value in a downstream settings file.
+JWT_AUTH = {
+    'JWT_ALGORITHM': 'HS256',
+    'JWT_AUDIENCE': 'course-discovery',
+    'JWT_ISSUER': 'course-discovery',
+    'JWT_DECODE_HANDLER': 'course_discovery.apps.api.jwt_decode_handler.decode',
+}
+
 SWAGGER_SETTINGS = {
     'api_version': 'v1',
     'doc_expansion': 'list',

course_discovery/settings/local.py

@@ -55,6 +55,8 @@ SOCIAL_AUTH_EDX_OIDC_ID_TOKEN_DECRYPTION_KEY = SOCIAL_AUTH_EDX_OIDC_SECRET
 
 ENABLE_AUTO_AUTH = True
 
+JWT_AUTH['JWT_SECRET_KEY'] = 'course-discovery-jwt-secret-key'
+
 #####################################################################
 # Lastly, see if the developer has any local overrides.
 if os.path.isfile(join(dirname(abspath(__file__)), 'private.py')):

course_discovery/settings/test.py

@@ -34,3 +34,5 @@ ELASTICSEARCH = {
     'host': os.environ.get('TEST_ELASTICSEARCH_HOST', 'localhost'),
     'index': 'course_discovery_test',
 }
+
+JWT_AUTH['JWT_SECRET_KEY'] = 'course-discovery-jwt-secret-key'

requirements/base.txt

@@ -2,6 +2,7 @@ django == 1.8.7
 django-extensions == 1.5.9
 django-waffle == 0.11
 djangorestframework == 3.3.1
+djangorestframework-jwt==1.7.2
 django-rest-swagger[reST]==0.3.4
 edx-auth-backends == 0.1.3
 edx-rest-api-client==1.2.1