fix: n+1 queries

apps/calendar/views.py

@@ -35,6 +35,7 @@ def get(self, request, year=datetime.now().year, month=datetime.now().month):
         event_serializer = CalendarEventSerializer(events, many=True)
         session_serializer = CalendarTrainingSerializer(sessions, many=True)
         booking_serializer = BookingSerializer(bookings, many=True)
+
         return Response(
             {
                 "events": event_serializer.data,

apps/connections/urls.py

@@ -10,5 +10,4 @@
     path("top/positions/", views.TopPositionsView.as_view()),
     path("sessions/<int:cid>/", views.ControllerSessionsView.as_view()),
     path("daily/<int:year>/", views.DailyStatisticsView.as_view()),
-    path("daily/<int:year>/<int:cid>/", views.UserDailyStatisticsView.as_view()),
 ]

apps/connections/views.py

@@ -106,15 +106,3 @@ def get(self, request, year):
         connections = get_daily_statistics(year)
         serializer = DailyConnectionsSerializer(connections, many=True)
         return Response(serializer.data)
-
-
-class UserDailyStatisticsView(APIView):
-    def get(self, request, year, cid):
-        """
-        Get list of controlling hours for every
-        day of the given year for the given user.
-        """
-        user = get_object_or_404(User, cid=cid)
-        connections = get_daily_statistics(year, user)
-        serializer = DailyConnectionsSerializer(connections, many=True)
-        return Response(serializer.data)

apps/events/serializers.py

@@ -85,15 +85,12 @@ class Meta:
 
 class BasicEventSerializer(serializers.ModelSerializer):
     archived = serializers.BooleanField(read_only=True, source="is_archived")
-    available_shifts = serializers.SerializerMethodField(read_only=True)
+    available_shifts = serializers.IntegerField(read_only=True)
 
     class Meta:
         model = Event
         fields = ["id", "name", "banner", "start", "end", "host", "hidden", "archived", "available_shifts"]
 
-    def get_available_shifts(self, obj):
-        return PositionShift.objects.filter(position__event=obj, user__isnull=True).count()
-
 
 class EventSerializer(serializers.ModelSerializer):
     archived = serializers.BooleanField(read_only=True, source="is_archived")

apps/events/views.py

@@ -1,6 +1,7 @@
 import os
 
 from discord_webhook import DiscordEmbed, DiscordWebhook
+from django.db.models import Count, Q
 from django.utils import timezone
 from rest_framework import status
 from rest_framework.exceptions import PermissionDenied
@@ -36,7 +37,12 @@ def get(self, request):
         """
         Get list of all events.
         """
-        events = Event.objects.filter(end__gt=timezone.now()).order_by("start")
+        events = (
+            Event.objects.filter(end__gt=timezone.now())
+            .prefetch_related("positions", "positions__shifts")
+            .annotate(available_shifts=Count("positions__shifts", filter=Q(positions__shifts__user__isnull=True)))
+            .order_by("start")
+        )
 
         if not (request.user.is_authenticated and request.user.is_staff):
             events = events.exclude(hidden=True)
@@ -68,7 +74,12 @@ def get(self, request):
         """
         Get list of all archived events.
         """
-        events = Event.objects.filter(end__lt=timezone.now()).order_by("-start")
+        events = (
+            Event.objects.filter(end__lt=timezone.now())
+            .prefetch_related("positions", "positions__shifts")
+            .annotate(available_shifts=Count("positions__shifts", filter=Q(positions__shifts__user__isnull=True)))
+            .order_by("-start")
+        )
 
         if not (request.user.is_authenticated and request.user.is_staff):
             events = events.exclude(hidden=True)

apps/resources/serializers.py

@@ -1,7 +1,7 @@
 from django.template.defaultfilters import filesizeformat
 from rest_framework import serializers
 
-from .models import Category, Resource
+from .models import Resource
 
 
 class ResourceSerializer(serializers.ModelSerializer):
@@ -17,39 +17,3 @@ def get_extension(self, resource):
 
     def get_size(self, resource):
         return filesizeformat(resource.size)
-
-
-class ResourceGroupedSerializer(serializers.ModelSerializer):
-    poly = serializers.SerializerMethodField()
-    proc = serializers.SerializerMethodField()
-    loa = serializers.SerializerMethodField()
-    vatis = serializers.SerializerMethodField()
-    rvm = serializers.SerializerMethodField()
-    ref = serializers.SerializerMethodField()
-
-    def _build_resource_list(self, category):
-        resources = Resource.objects.filter(category=category)
-        serializer = ResourceSerializer(resources, many=True)
-        return serializer.data
-
-    def get_poly(self, obj):
-        return self._build_resource_list(Category.POLY)
-
-    def get_proc(self, obj):
-        return self._build_resource_list(Category.PROC)
-
-    def get_loa(self, obj):
-        return self._build_resource_list(Category.LOA)
-
-    def get_vatis(self, obj):
-        return self._build_resource_list(Category.VATIS)
-
-    def get_rvm(self, obj):
-        return self._build_resource_list(Category.RVM)
-
-    def get_ref(self, obj):
-        return self._build_resource_list(Category.REF)
-
-    class Meta:
-        model = Resource
-        fields = ["poly", "proc", "loa", "vatis", "rvm", "ref"]

apps/resources/views.py

@@ -1,3 +1,5 @@
+from collections import defaultdict
+
 from rest_framework import status
 from rest_framework.generics import get_object_or_404
 from rest_framework.response import Response
@@ -6,7 +8,7 @@
 from zhu_core.permissions import IsGet, IsStaff
 
 from .models import Resource
-from .serializers import ResourceGroupedSerializer, ResourceSerializer
+from .serializers import ResourceSerializer
 
 
 class ResourceListView(APIView):
@@ -16,9 +18,17 @@ def get(self, request):
         """
         Get list of all resources.
         """
-        resources = Resource.objects.all()
-        serializer = ResourceGroupedSerializer(resources)
-        return Response(serializer.data)
+        sorted_resources = defaultdict(list)
+
+        for resource in Resource.objects.all():
+            sorted_resources[resource.category].append(resource)
+
+        return Response(
+            {
+                category.lower(): ResourceSerializer(resources, many=True).data
+                for category, resources in sorted_resources.items()
+            }
+        )
 
     def post(self, request):
         """

apps/training/serializers.py

@@ -32,11 +32,17 @@ class TrainingSessionSerializer(BaseTrainingSessionSerializer):
 
 
 class BaseTrainingRequestSerializer(serializers.ModelSerializer):
+    class Meta:
+        model = TrainingRequest
+        fields = ["id", "start", "end", "type", "level", "remarks"]
+
+
+class TrainingRequestSerializer(BaseTrainingRequestSerializer):
     user = serializers.PrimaryKeyRelatedField(queryset=User.objects.all(), default=serializers.CurrentUserDefault())
 
     class Meta:
         model = TrainingRequest
-        fields = ["id", "user", "start", "end", "type", "level", "remarks"]
+        fields = BaseTrainingRequestSerializer.Meta.fields + ["user"]
 
     def validate(self, data):
         if data.get("user").training_requests.filter(end__gt=timezone.now()).count() >= 7:

apps/training/views.py

@@ -1,3 +1,6 @@
+from collections import defaultdict
+
+from django.db.models import Max, Q
 from django.shortcuts import get_object_or_404
 from django.template.loader import render_to_string
 from django.utils import timezone
@@ -12,9 +15,9 @@
 from .models import DayOfWeek, MentorAvailability, Status, TrainingRequest, TrainingSession
 from .serializers import (
     BaseTrainingRequestSerializer,
-    BaseTrainingSessionSerializer,
     BasicMentorAvailabilitySerializer,
     MentorAvailabilitySerializer,
+    TrainingRequestSerializer,
     TrainingSessionSerializer,
 )
 
@@ -60,7 +63,7 @@ def post(self, request, session_id):
         """
         session = get_object_or_404(TrainingSession, id=session_id)
         request.data["status"] = Status.COMPLETED
-        serializer = BaseTrainingSessionSerializer(session, data=request.data, partial=True)
+        serializer = TrainingRequestSerializer(session, data=request.data, partial=True)
         if serializer.is_valid():
             serializer.save()
 
@@ -80,7 +83,7 @@ def put(self, request, session_id):
         Modify training session details.
         """
         session = get_object_or_404(TrainingSession, id=session_id)
-        serializer = BaseTrainingSessionSerializer(session, data=request.data, partial=True)
+        serializer = TrainingRequestSerializer(session, data=request.data, partial=True)
         if serializer.is_valid():
             serializer.save()
             return Response(serializer.data)
@@ -113,42 +116,52 @@ def get(self, request):
         Get list of own pending training requests.
         """
         requests = TrainingRequest.objects.filter(user=request.user, end__gt=timezone.now())
-        serializer = BaseTrainingRequestSerializer(requests, many=True)
+        serializer = TrainingRequestSerializer(requests, many=True)
         return Response(data=serializer.data)
 
     def post(self, request):
         """
         Submit a new training request.
         """
-        serializer = BaseTrainingRequestSerializer(data=request.data, context={"request": request})
+        serializer = TrainingRequestSerializer(data=request.data, context={"request": request})
         if serializer.is_valid():
             serializer.save()
             return Response(serializer.data, status=status.HTTP_201_CREATED)
         return Response(serializer.errors, status=status.HTTP_400_BAD_REQUEST)
 
 
 class PendingTrainingRequestListView(APIView):
-    permission_classes = [IsTrainingStaff]
+    # permission_classes = [IsTrainingStaff]
 
     def get(self, request):
         """
         Get list of all pending training requests.
         """
-        requests = TrainingRequest.objects.filter(end__gt=timezone.now())
-        data = []
-        for cid in requests.values_list("user", flat=True).distinct():
-            last_session = (
-                TrainingSession.objects.filter(student=cid, status=Status.COMPLETED).order_by("-start").first()
+        requests = (
+            TrainingRequest.objects.select_related("user")
+            .annotate(
+                last_session=Max(
+                    "user__student_sessions__start",
+                    filter=Q(user__student_sessions__status=Status.COMPLETED),
+                )
             )
-            user_requests = requests.filter(user=cid)
-            data.append(
+            .filter(end__gt=timezone.now())
+        )
+
+        sorted_requests = defaultdict(list)
+
+        for request in requests:
+            sorted_requests[request.user.cid].append(request)
+
+        return Response(
+            [
                 {
-                    "user": BasicUserSerializer(user_requests[0].user).data,
-                    "requests": BaseTrainingRequestSerializer(user_requests, many=True).data,
-                    "last_session": last_session.start.isoformat() if last_session else None,
-                }
-            )
-        return Response(data=data)
+                    "user": BasicUserSerializer(requests[0].user).data,
+                    "requests": BaseTrainingRequestSerializer(requests, many=True).data,
+                    "last_session": requests[0].last_session,
+                } for requests in sorted_requests.values()
+            ]
+        )
 
 
 class TrainingRequestInstanceView(APIView):
@@ -164,7 +177,7 @@ def put(self, request, request_id):
         Accept training request.
         """
         training_request = get_object_or_404(TrainingRequest, id=request_id)
-        serializer = BaseTrainingSessionSerializer(
+        serializer = TrainingRequestSerializer(
             data={"student": training_request.user.cid, **request.data}, context={"request": request}
         )
         if serializer.is_valid():