Add document folder list API endpoint

mayan/apps/folders/api_views.py

@@ -1,7 +1,13 @@
 from __future__ import absolute_import
 
+from django.core.exceptions import PermissionDenied
+from django.shortcuts import get_object_or_404
+
 from rest_framework import generics
 
+from documents.models import Document
+from documents.permissions import PERMISSION_DOCUMENT_VIEW
+from permissions.models import Permission
 from rest_api.filters import MayanObjectPermissionsFilter
 from rest_api.permissions import MayanPermission
 
@@ -41,3 +47,25 @@ class APIFolderView(generics.RetrieveUpdateDestroyAPIView):
         'PATCH': [PERMISSION_FOLDER_EDIT],
         'DELETE': [PERMISSION_FOLDER_DELETE]
     }
+
+
+class APIDocumentFolderListView(generics.ListAPIView):
+    """
+    Returns a list of all the folders to which a document belongs.
+    """
+
+    serializer_class = FolderSerializer
+
+    permission_classes = (MayanPermission,)
+    filter_backends = (MayanObjectPermissionsFilter,)
+    mayan_object_permissions = {'GET': [PERMISSION_FOLDER_VIEW]}
+
+    def get_queryset(self):
+        document = get_object_or_404(Document, pk=self.kwargs['pk'])
+        try:
+            Permission.objects.check_permissions(self.request.user, [PERMISSION_DOCUMENT_VIEW])
+        except PermissionDenied:
+            AccessEntry.objects.check_access(PERMISSION_DOCUMENT_VIEW, self.request.user, document)
+
+        queryset = document.folders.all()
+        return queryset