perf(SourceDetailView, SourceBrowseChantsView, permissions): reduce q…

…ueries

django/cantusdb_project/main_app/permissions.py

@@ -1,15 +1,18 @@
+from typing import Optional, Union
 from django.db.models import Q
-from typing import Optional
+from django.core.exceptions import PermissionDenied
+from django.contrib.auth.models import AnonymousUser
 from main_app.models import (
     Source,
     Chant,
     Sequence,
 )
 from users.models import User
-from django.core.exceptions import PermissionDenied
 
 
-def user_can_edit_chants_in_source(user: User, source: Optional[Source]) -> bool:
+def user_can_edit_chants_in_source(
+    user: Union[User, AnonymousUser], source: Optional[Source]
+) -> bool:
     """
     Checks if the user can edit Chants in a given Source.
     Used in ChantDetail, ChantList, ChantCreate, ChantDelete, ChantEdit,
@@ -22,16 +25,17 @@ def user_can_edit_chants_in_source(user: User, source: Optional[Source]) -> bool
         return False
 
     source_id = source.id
-    user_is_assigned_to_source: bool = user.sources_user_can_edit.filter(  # noqa
+    user_is_assigned_to_source = user.sources_user_can_edit.filter(  # type: ignore[attr-defined]
         id=source_id
     ).exists()
 
-    user_is_project_manager: bool = user.groups.filter(name="project manager").exists()
-    user_is_editor: bool = user.groups.filter(name="editor").exists()
-    user_is_contributor: bool = user.groups.filter(name="contributor").exists()
+    user_groups = user.groups.all().values_list("name", flat=True)
+    user_is_pm = "project manager" in user_groups
+    user_is_editor = "editor" in user_groups
+    user_is_contributor = "contributor" in user_groups
 
     return (
-        user_is_project_manager
+        user_is_pm
         or (user_is_editor and user_is_assigned_to_source)
         or (user_is_editor and source.created_by == user)
         or (user_is_contributor and user_is_assigned_to_source)
@@ -51,14 +55,15 @@ def user_can_proofread_chant(user: User, chant: Chant) -> bool:
         return False
 
     source_id = chant.source.id
-    user_is_assigned_to_source: bool = user.sources_user_can_edit.filter(  # noqa
+    user_is_assigned_to_source = user.sources_user_can_edit.filter(  # type: ignore[attr-defined]
         id=source_id
     ).exists()
 
-    user_is_project_manager: bool = user.groups.filter(name="project manager").exists()
-    user_is_editor: bool = user.groups.filter(name="editor").exists()
+    user_groups = user.groups.all().values_list("name", flat=True)
+    user_is_pm = "project manager" in user_groups
+    user_is_editor = "editor" in user_groups
 
-    return user_is_project_manager or (user_is_editor and user_is_assigned_to_source)
+    return user_is_pm or (user_is_editor and user_is_assigned_to_source)
 
 
 def user_can_view_source(user: User, source: Source) -> bool:
@@ -100,16 +105,17 @@ def user_can_edit_sequences(user: User, sequence: Sequence) -> bool:
         return False
 
     source_id = source.id
-    user_is_assigned_to_source: bool = user.sources_user_can_edit.filter(  # noqa
+    user_is_assigned_to_source = user.sources_user_can_edit.filter(  # type: ignore[attr-defined]
         id=source_id
     ).exists()
 
-    user_is_project_manager: bool = user.groups.filter(name="project manager").exists()
-    user_is_editor: bool = user.groups.filter(name="editor").exists()
-    user_is_contributor: bool = user.groups.filter(name="contributor").exists()
+    user_groups = user.groups.all().values_list("name", flat=True)
+    user_is_pm = "project manager" in user_groups
+    user_is_editor = "editor" in user_groups
+    user_is_contributor = "contributor" in user_groups
 
     return (
-        user_is_project_manager
+        user_is_pm
         or (user_is_editor and user_is_assigned_to_source)
         or (user_is_editor and source.created_by == user)
         or (user_is_contributor and user_is_assigned_to_source)
@@ -136,11 +142,14 @@ def user_can_edit_source(user: User, source: Source) -> bool:
     if user.is_anonymous:
         return False
     source_id = source.id
-    assigned_to_source = user.sources_user_can_edit.filter(id=source_id)  # noqa
+    assigned_to_source = user.sources_user_can_edit.filter(  # type: ignore[attr-defined]
+        id=source_id
+    )
 
-    is_project_manager: bool = user.groups.filter(name="project manager").exists()
-    is_editor: bool = user.groups.filter(name="editor").exists()
-    is_contributor: bool = user.groups.filter(name="contributor").exists()
+    user_groups = user.groups.all().values_list("name", flat=True)
+    is_project_manager: bool = "project manager" in user_groups
+    is_editor: bool = "editor" in user_groups
+    is_contributor: bool = "contributor" in user_groups
 
     return (
         is_project_manager
@@ -152,8 +161,8 @@ def user_can_edit_source(user: User, source: Source) -> bool:
 
 def user_can_view_user_detail(viewing_user: User, user: User) -> bool:
     """
-    Checks if the user can view the user detail pages of regular users in the database or just indexers.
-    Used in UserDetailView.
+    Checks if the user can view the user detail pages of regular users in
+    the database or just indexers. Used in UserDetailView.
     """
     return viewing_user.is_authenticated or user.is_indexer
 

django/cantusdb_project/main_app/views/source.py

@@ -61,6 +61,7 @@ class SourceBrowseChantsView(ListView):
     context_object_name = "chants"
     template_name = "browse_chants.html"
     pk_url_kwarg = "source_id"
+    source: Source
 
     def get_queryset(self):
         """Gather the chants to be displayed.
@@ -73,6 +74,7 @@ def get_queryset(self):
         """
         source_id = self.kwargs.get(self.pk_url_kwarg)
         source = get_object_or_404(Source, id=source_id)
+        self.source = source
 
         display_unpublished = self.request.user.is_authenticated
         if (source.published is False) and (not display_unpublished):
@@ -104,8 +106,7 @@ def get_queryset(self):
 
     def get_context_data(self, **kwargs):
         context: dict = super().get_context_data(**kwargs)
-        source_id: int = self.kwargs.get(self.pk_url_kwarg)
-        source: Source = get_object_or_404(Source, id=source_id)
+        source: Source = self.source
         if source.segment_id != CANTUS_SEGMENT_ID:
             # the chant list ("Browse Chants") page should only be visitable
             # for sources in the CANTUS Database segment, as sources in the Bower
@@ -175,11 +176,11 @@ class SourceDetailView(DetailView):
 
     def get_queryset(self):
         return self.model.objects.select_related(
-            "holding_institution", "segment", "provenance"
+            "holding_institution", "segment", "provenance", "created_by"
         ).all()
 
     def get_context_data(self, **kwargs):
-        source = self.get_object()
+        source = self.object
         user = self.request.user
 
         if not user_can_view_source(user, source):