Allow subclassing JSONWebTokenAuthentication

Author: cancan101

rest_framework_jwt/authentication.py

@@ -13,39 +13,20 @@
 jwt_get_user_id_from_payload = api_settings.JWT_PAYLOAD_GET_USER_ID_HANDLER
 
 
-class JSONWebTokenAuthentication(BaseAuthentication):
+class JSONWebTokenAuthenticationBase(BaseAuthentication):
     """
     Token based authentication using the JSON Web Token standard.
-
-    Clients should authenticate by passing the token key in the "Authorization"
-    HTTP header, prepended with the string specified in the setting
-    `JWT_AUTH_HEADER_PREFIX`. For example:
-
-        Authorization: JWT eyJhbGciOiAiSFMyNTYiLCAidHlwIj
     """
-    www_authenticate_realm = 'api'
 
     def authenticate(self, request):
         """
         Returns a two-tuple of `User` and token if a valid signature has been
         supplied using JWT-based authentication.  Otherwise returns `None`.
         """
-        auth = get_authorization_header(request).split()
-        auth_header_prefix = api_settings.JWT_AUTH_HEADER_PREFIX.lower()
-
-        if not auth or smart_text(auth[0].lower()) != auth_header_prefix:
-            return None
-
-        if len(auth) == 1:
-            msg = _('Invalid Authorization header. No credentials provided.')
-            raise exceptions.AuthenticationFailed(msg)
-        elif len(auth) > 2:
-            msg = _('Invalid Authorization header. Credentials string '
-                    'should not contain spaces.')
-            raise exceptions.AuthenticationFailed(msg)
+        jwt_value = self.get_jwt_value(request)
 
         try:
-            payload = jwt_decode_handler(auth[1])
+            payload = jwt_decode_handler(jwt_value)
         except jwt.ExpiredSignature:
             msg = _('Signature has expired.')
             raise exceptions.AuthenticationFailed(msg)
@@ -55,28 +36,56 @@ def authenticate(self, request):
 
         user = self.authenticate_credentials(payload)
 
-        return (user, auth[1])
+        return (user, jwt_value)
 
     def authenticate_credentials(self, payload):
         """
         Returns an active user that matches the payload's user id and email.
         """
         User = utils.get_user_model()
 
-        try:
-            user_id = jwt_get_user_id_from_payload(payload)
+        user_id = jwt_get_user_id_from_payload(payload)
 
-            if user_id is not None:
+        if user_id is not None:
+            try:
                 user = User.objects.get(pk=user_id, is_active=True)
-            else:
-                msg = _('Invalid payload.')
+            except User.DoesNotExist:
+                msg = _('Invalid signature.')
                 raise exceptions.AuthenticationFailed(msg)
-        except User.DoesNotExist:
-            msg = _('Invalid signature.')
+        else:
+            msg = _('Invalid payload.')
             raise exceptions.AuthenticationFailed(msg)
 
         return user
 
+
+class JSONWebTokenAuthentication(JSONWebTokenAuthenticationBase):
+    """
+    Clients should authenticate by passing the token key in the "Authorization"
+    HTTP header, prepended with the string specified in the setting
+    `JWT_AUTH_HEADER_PREFIX`. For example:
+
+        Authorization: JWT eyJhbGciOiAiSFMyNTYiLCAidHlwIj
+    """
+    www_authenticate_realm = 'api'
+
+    def get_jwt_value(self, request):
+        auth = get_authorization_header(request).split()
+        auth_header_prefix = api_settings.JWT_AUTH_HEADER_PREFIX.lower()
+
+        if not auth or smart_text(auth[0].lower()) != auth_header_prefix:
+            return None
+
+        if len(auth) == 1:
+            msg = _('Invalid Authorization header. No credentials provided.')
+            raise exceptions.AuthenticationFailed(msg)
+        elif len(auth) > 2:
+            msg = _('Invalid Authorization header. Credentials string '
+                    'should not contain spaces.')
+            raise exceptions.AuthenticationFailed(msg)
+
+        return auth[1]
+
     def authenticate_header(self, request):
         """
         Return a string to be used as the value of the `WWW-Authenticate`