chore: Reduce number of queries by prefetching foreign key objects on…

… comment

- the fetched objects are user, reaction and flag.

comment/api/serializers.py

@@ -161,7 +161,7 @@ class Meta:
     @staticmethod
     def get_users(obj):
         users = {'likes': [], 'dislikes': []}
-        for instance in obj.reactions.all():
+        for instance in obj.reactions.all().select_related('user'):
             user_info = {
                 'id': instance.user.id,
                 'username': instance.user.USERNAME_FIELD
@@ -189,7 +189,7 @@ def get_reporters(obj):
                 'id': flag_instance.user.id,
                 'username': flag_instance.user.USERNAME_FIELD
             }
-            for flag_instance in obj.flags.all()
+            for flag_instance in obj.flags.all().select_related('user')
         ]
 
     @staticmethod

comment/api/views.py

@@ -1,6 +1,5 @@
 from django.core.exceptions import ValidationError
 from rest_framework import generics, permissions, status
-from rest_framework.generics import get_object_or_404
 from rest_framework.response import Response
 from rest_framework.views import APIView
 
@@ -37,17 +36,17 @@ class CommentList(ContentTypeValidator, generics.ListAPIView):
 
     def get_queryset(self):
         self.validate(self.request)
-        return Comment.objects.filter_parents_by_object(self.model_obj)
+        return Comment.objects.filter_parents_by_object(self.model_obj).select_related('user', 'reaction', 'flag')
 
 
 class CommentDetail(generics.RetrieveUpdateDestroyAPIView):
-    queryset = Comment.objects.all()
+    queryset = Comment.objects.all().select_related('user', 'reaction', 'flag')
     serializer_class = CommentSerializer
     permission_classes = (permissions.IsAuthenticatedOrReadOnly, IsOwnerOrReadOnly, UserPermittedOrReadOnly)
 
 
 class CommentDetailForReaction(generics.UpdateAPIView):
-    queryset = Comment.objects.all()
+    queryset = Comment.objects.all().select_related('user', 'reaction', 'flag')
     serializer_class = CommentSerializer
     permission_classes = (permissions.IsAuthenticatedOrReadOnly, UserPermittedOrReadOnly)
 
@@ -57,7 +56,7 @@ def get_serializer_context(self):
         return context
 
     def post(self, request, *args, **kwargs):
-        comment = get_object_or_404(Comment, id=kwargs.get('pk'))
+        comment = self.get_object()
         reaction_type = kwargs.get('reaction', None)
         reaction_obj = Reaction.objects.get_reaction_object(comment)
         try:
@@ -75,7 +74,7 @@ def post(self, request, *args, **kwargs):
 
 
 class CommentDetailForFlag(generics.UpdateAPIView):
-    queryset = Comment.objects.all()
+    queryset = Comment.objects.all().select_related('user', 'reaction', 'flag')
     serializer_class = CommentSerializer
     permission_classes = (permissions.IsAuthenticatedOrReadOnly, FlagEnabledPermission, UserPermittedOrReadOnly)
 
@@ -85,7 +84,7 @@ def get_serializer_context(self):
         return context
 
     def post(self, request, *args, **kwargs):
-        comment = get_object_or_404(Comment, id=kwargs.get('pk'))
+        comment = self.get_object()
         flag = Flag.objects.get_for_comment(comment)
         reason = request.data.get('reason') or request.POST.get('reason')
         info = request.data.get('info') or request.POST.get('info')
@@ -99,7 +98,7 @@ def post(self, request, *args, **kwargs):
 
 
 class CommentDetailForFlagStateChange(generics.UpdateAPIView):
-    queryset = Comment.objects.all()
+    queryset = Comment.objects.all().select_related('user', 'reaction', 'flag')
     serializer_class = CommentSerializer
     permission_classes = (CanChangeFlaggedCommentState, UserPermittedOrReadOnly)
 

comment/views/comments.py

@@ -1,4 +1,4 @@
-from django.shortcuts import render, get_object_or_404, redirect
+from django.shortcuts import render, redirect, get_object_or_404
 from django.template.loader import render_to_string
 from django.utils import timezone
 from django.contrib import messages
@@ -54,7 +54,10 @@ class UpdateComment(CanEditMixin, BaseCommentView):
     comment = None
 
     def get_object(self):
-        self.comment = get_object_or_404(Comment, pk=self.kwargs.get('pk'))
+        self.comment = get_object_or_404(
+            Comment.objects.select_related('user', 'flag', 'reaction'),
+            pk=self.kwargs.get('pk')
+        )
         return self.comment
 
     def get(self, request, *args, **kwargs):
@@ -78,7 +81,10 @@ class DeleteComment(CanDeleteMixin, BaseCommentView):
     comment = None
 
     def get_object(self):
-        self.comment = get_object_or_404(Comment, pk=self.kwargs.get('pk'))
+        self.comment = get_object_or_404(
+            Comment.objects.select_related('user', 'flag', 'reaction'),
+            pk=self.kwargs.get('pk')
+        )
         return self.comment
 
     def get(self, request, *args, **kwargs):

comment/views/flags.py

@@ -3,16 +3,19 @@
 from django.views import View
 
 from comment.models import Comment, Flag, FlagInstance
-from comment.mixins import CanSetFlagMixin, CanUpdateFlagStateMixin
+from comment.mixins import CanSetFlagMixin, CanUpdateFlagStateMixin, BaseCommentMixin
 from comment.responses import UTF8JsonResponse, DABResponseData
 from comment.messages import FlagInfo, FlagError
 
 
-class SetFlag(CanSetFlagMixin, View, DABResponseData):
+class SetFlag(CanSetFlagMixin, BaseCommentMixin, View, DABResponseData):
     comment = None
 
     def get_object(self):
-        self.comment = get_object_or_404(Comment, pk=self.kwargs.get('pk'))
+        self.comment = get_object_or_404(
+            Comment.objects.select_related('user', 'reaction', 'flag'),
+            pk=self.kwargs.get('pk')
+        )
         return self.comment
 
     def post(self, request, *args, **kwargs):
@@ -41,7 +44,10 @@ class ChangeFlagState(CanUpdateFlagStateMixin, View, DABResponseData):
     comment = None
 
     def get_object(self):
-        self.comment = get_object_or_404(Comment, pk=self.kwargs.get('pk'))
+        self.comment = get_object_or_404(
+            Comment.objects.select_related('user', 'reaction', 'flag'),
+            pk=self.kwargs.get('pk')
+        )
         return self.comment
 
     def post(self, request, *args, **kwargs):

comment/views/reactions.py

@@ -4,17 +4,19 @@
 from django.views import View
 from django.views.decorators.http import require_POST
 
-from comment.models import Comment, Reaction, ReactionInstance
 from comment.mixins import BaseCommentMixin
+from comment.models import Comment, Reaction, ReactionInstance
 from comment.responses import UTF8JsonResponse, DABResponseData
 from comment.messages import ReactionInfo
 
 
 @method_decorator(require_POST, name='dispatch')
 class SetReaction(BaseCommentMixin, View, DABResponseData):
-
     def post(self, request, *args, **kwargs):
-        comment = get_object_or_404(Comment, id=kwargs.get('pk'))
+        comment = get_object_or_404(
+            Comment.objects.select_related('user', 'reaction', 'flag'),
+            pk=self.kwargs.get('pk')
+        )
         reaction_type = kwargs.get('reaction', None)
         reaction_obj = Reaction.objects.get_reaction_object(comment)
         try: