Implement OAuth2 scopes based on permissions

Signed-off-by: Yohann D'ANELLO <ynerant@crans.org>

apps/permission/scopes.py

@@ -0,0 +1,36 @@
+# Copyright (C) 2018-2021 by BDE ENS Paris-Saclay
+# SPDX-License-Identifier: GPL-3.0-or-later
+
+from oauth2_provider.scopes import BaseScopes
+
+from member.models import Club
+
+from .backends import PermissionBackend
+from .models import Permission
+
+
+class PermissionScopes(BaseScopes):
+    """
+    An OAuth2 scope is defined by a permission object and a club.
+    A token will have a subset of permissions from the owner of the application,
+    and can be useful to make queries through the API with limited privileges.
+    """
+
+    def get_all_scopes(self):
+        return {f"{p.id}_{club.id}": f"{p.description} (club {club.name})"
+                for p in Permission.objects.all() for club in Club.objects.all()}
+
+    def get_available_scopes(self, application=None, request=None, *args, **kwargs):
+        if not application:
+            return []
+        user = application.user
+        return [f"{p.id}_{p.membership.club.id}"
+                for t in Permission.PERMISSION_TYPES
+                for p in PermissionBackend.get_raw_permissions(user, t[0])]
+
+    def get_default_scopes(self, application=None, request=None, *args, **kwargs):
+        if not application:
+            return []
+        user = application.user
+        return [f"{p.id}_{p.membership.club.id}"
+                for p in PermissionBackend.get_raw_permissions(user, 'view')]