oops - add decorators for federated APIs

mediagoblin/federation/decorators.py

@@ -0,0 +1,51 @@
+# GNU MediaGoblin -- federated, autonomous media hosting
+# Copyright (C) 2011, 2012 MediaGoblin contributors.  See AUTHORS.
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU Affero General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU Affero General Public License for more details.
+#
+# You should have received a copy of the GNU Affero General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+from functools import wraps
+
+from mediagoblin.db.models import User
+from mediagoblin.decorators import require_active_login
+from mediagoblin.tools.response import json_response
+
+def user_has_privilege(privilege_name):
+    """
+    Requires that a user have a particular privilege in order to access a page.
+    In order to require that a user have multiple privileges, use this
+    decorator twice on the same view. This decorator also makes sure that the
+    user is not banned, or else it redirects them to the "You are Banned" page.
+
+        :param privilege_name       A unicode object that is that represents
+                                        the privilege object. This object is
+                                        the name of the privilege, as assigned
+                                        in the Privilege.privilege_name column
+    """
+
+    def user_has_privilege_decorator(controller):
+        @wraps(controller)
+        @require_active_login
+        def wrapper(request, *args, **kwargs):
+            user_id = request.user.id
+            if not request.user.has_privilege(privilege_name):
+                error = "User '{0}' needs '{1}' privilege".format(
+                    request.user.username,
+                    privilege_name
+                )
+                return json_response({"error": error}, status=403)
+
+            return controller(request, *args, **kwargs)
+
+        return wrapper
+    return user_has_privilege_decorator
+