0.1.6 - JWT refactoring including custom django middleware and auth b…

…ackend

README.rst

@@ -10,7 +10,7 @@ Features
 - JSONApiResponseMixin providing render_api_response and render_api_error_response methods
 - Accept JSON request payload
 - JSONApiFormView that can be used for simple JSON APIs using django.forms
-- JSON Web token validation (pending to be moved into separate package)
+- JSON Web token validation (custom django middleware&auth backend)
 - JSONTestClient providing utilities that can be used to test created APIs
 - Default JSONEncoder handling Decimal numbers
 - Simple jsonify template filter (add 'jsonis' to your application list in settings)

jsonis/jwt/__init__.py

@@ -0,0 +1 @@
+from views import JWTAuthorizationMixin

jsonis/jwt/auth_backends.py

@@ -0,0 +1,18 @@
+from django.contrib.auth import get_user_model
+from django.contrib.auth.backends import ModelBackend
+
+from .utils import parse_token, JWTParseError
+
+class JWTAuthenticationBackend(ModelBackend):
+    """Custom django authentication backend using JWT"""
+    def authenticate(self, authorization_token=None, **kwargs):
+        UserModel = get_user_model()
+        if authorization_token is None:
+            return
+        try:
+            token_data = parse_token(authorization_token)
+            return UserModel._default_manager.get(pk=token_data['id'])
+        except JWTParseError:
+            pass
+        except UserModel.DoesNotExist:
+            pass

jsonis/jwt/middleware.py

@@ -0,0 +1,37 @@
+from django.contrib.auth import authenticate, login, get_user_model
+from django.core.exceptions import ImproperlyConfigured
+
+class JWTAuthMiddleware(object):
+    """Authentication Middleware that checks for a JSON Web Token in the Authorization header
+
+    JWTAuthenticationBackend needs to be added to AUTHENTICATION_BACKENDS as well"""
+
+    # Used HTTP Header
+    header = 'HTTP_AUTHORIZATION'
+
+    # Required header prefix
+    required_auth_prefix = 'Bearer'
+
+    def process_request(self, request):
+        if not hasattr(request, 'user'):
+            raise ImproperlyConfigured(
+                "The JWT auth middleware requires the authentication middleware to be installed. Edit your"
+                " MIDDLEWARE_CLASSES setting to insert 'django.contrib.auth.middleware.AuthenticationMiddleware'"
+                " before the JWTAuthMiddleware class.")
+
+        try:
+            auth_prefix, auth_token = request.META[self.header].split(' ')
+            if auth_prefix != self.required_auth_prefix:
+                raise ValueError
+
+            user = authenticate(authorization_token=auth_token)
+            if user:
+                request.user = user
+                login(request, user)
+
+        except KeyError:
+            # There is no self.header
+            pass
+        except ValueError:
+            # Header prefix doesn't match
+            pass

jsonis/jwt/utils.py

@@ -0,0 +1,29 @@
+import jwt
+
+from django.conf import settings
+
+class JWTParseError(Exception):
+    pass
+
+class JWTDecodeError(JWTParseError):
+    pass
+
+class JWTExpiredError(JWTParseError):
+    pass
+
+class JWTNoDataError(JWTDecodeError):
+    pass
+
+def parse_token(auth_token):
+    """Parser given JSON Web Token and returns contained data"""
+    try:
+        decoded_token = jwt.decode(auth_token, settings.FIREBASE_SECRET)
+    except (jwt.DecodeError, ValueError):
+        raise JWTDecodeError('Decoding of authorization token failed')
+    except jwt.ExpiredSignature:
+        raise JWTExpiredError('Expired authorization token')
+
+    try:
+        return decoded_token['d']
+    except (TypeError, KeyError):
+        raise JWTNoDataError('No data in authorization token')

jsonis/jwt.py → jsonis/jwt/views.py

@@ -1,17 +1,16 @@
-from __future__ import absolute_import
-
-import jwt
-
-from django.conf import settings
 from django.contrib.auth import get_user_model
 from django.utils.decorators import method_decorator
 from django.views.decorators.csrf import csrf_exempt
 
-from .views import JSONApiResponseMixin
+from jsonis.views import JSONApiResponseMixin
+from .utils import parse_token, JWTParseError
 
 
 class JWTAuthorizationMixin(JSONApiResponseMixin):
-    """JSON API mixin that enables JSON Web Token authorization"""
+    """JSON API mixin that enables JSON Web Token authorization
+
+    FIXME: Deprecated, move to middleware & auth backend"""
+
     @method_decorator(csrf_exempt)
     def dispatch(self, request, *args, **kwargs):
         if request.user.is_authenticated():
@@ -20,20 +19,15 @@ def dispatch(self, request, *args, **kwargs):
             try:
                 auth_prefix, auth_token = request.META['HTTP_AUTHORIZATION'].split(' ')
                 if auth_prefix != 'Bearer':
-                    raise ValueError
-                token_data = jwt.decode(auth_token, settings.FIREBASE_SECRET)
+                    return self.render_api_error_response('Not authenticated - Bad authorization header', status=401)
+                token_data = parse_token(auth_token)
             except KeyError:
                 return self.render_api_error_response('Not authenticated - Missing authorization header', status=401)
-            except ValueError:
-                return self.render_api_error_response('Not authenticated - Bad authorization header', status=401)
-            except jwt.DecodeError:
-                return self.render_api_error_response('Not authenticated - Bad authorization header (decode failed)',
-                                                      status=401)
-            except jwt.ExpiredSignature:
-                return self.render_api_error_response('Not authenticated - Expired authorization header', status=401)
+            except JWTParseError as e:
+                return self.render_api_error_response('Not authenticated - %s' % e, status=401)
 
             try:
-                self.user = get_user_model().objects.get(pk=token_data['d']['id'])
+                self.user = get_user_model().objects.get(pk=token_data['id'])
             except (TypeError, KeyError):
                 return self.render_api_error_response('Not authenticated - Bad authorization header data', status=401)
             except get_user_model().DoesNotExist:

setup.py

@@ -1,14 +1,14 @@
 #!/usr/bin/env python
 
-from distutils.core import setup
+from setuptools import setup
 
 setup(
     name='django-jsonis',
-    version='0.1.5',
+    version='0.1.6',
     description='Django JSON Utils',
     author='Tomas Rychlik',
     author_email='[email protected]',
-    packages=['jsonis', 'jsonis.templatetags'],
+    packages=['jsonis', 'jsonis.templatetags', 'jsonis.jwt'],
     license='MIT',
     url='https://github.com/rychlis/django-jsonis',
     install_requires=[