Enhance performance by prefetching more

chzzk/tests/test_views.py

@@ -1,7 +1,9 @@
 from datetime import timedelta
 from typing import TYPE_CHECKING
 
+from django.db import connection
 from django.test import TestCase
+from django.test.utils import CaptureQueriesContext
 from django.urls import reverse
 from django.utils import timezone
 
@@ -16,6 +18,75 @@ if TYPE_CHECKING:
 class ChzzkDashboardViewTests(TestCase):
     """Test cases for the dashboard view of the chzzk app."""
 
+    def test_dashboard_view_no_n_plus_one_on_rewards(self) -> None:
+        """Test that the dashboard view does not trigger an N+1 query for rewards."""
+        now = timezone.now()
+        base_kwargs = {
+            "category_type": "game",
+            "category_id": "1",
+            "category_value": "TestGame",
+            "service_id": "chzzk",
+            "state": "ACTIVE",
+            "start_date": now - timedelta(days=1),
+            "end_date": now + timedelta(days=1),
+            "has_ios_based_reward": False,
+            "drops_campaign_not_started": False,
+            "source_api": "unit-test",
+        }
+        reward_kwargs = {
+            "reward_type": "ITEM",
+            "campaign_reward_type": "Standard",
+            "condition_type": "watch",
+            "ios_based_reward": False,
+            "code_remaining_count": 100,
+        }
+
+        campaign1 = ChzzkCampaign.objects.create(
+            campaign_no=9001,
+            title="C1",
+            **base_kwargs,
+        )
+        campaign1.rewards.create(  # pyright: ignore[reportAttributeAccessIssue]
+            reward_no=901,
+            title="R1",
+            condition_for_minutes=10,
+            **reward_kwargs,
+        )  # pyright: ignore[reportAttributeAccessIssue]
+        campaign2 = ChzzkCampaign.objects.create(
+            campaign_no=9002,
+            title="C2",
+            **base_kwargs,
+        )
+        campaign2.rewards.create(  # pyright: ignore[reportAttributeAccessIssue]
+            reward_no=902,
+            title="R2",
+            condition_for_minutes=20,
+            **reward_kwargs,
+        )  # pyright: ignore[reportAttributeAccessIssue]
+
+        with CaptureQueriesContext(connection) as one_campaign_ctx:
+            self.client.get(reverse("chzzk:dashboard"))
+        query_count_two = len(one_campaign_ctx)
+
+        campaign3 = ChzzkCampaign.objects.create(
+            campaign_no=9003,
+            title="C3",
+            **base_kwargs,
+        )
+        campaign3.rewards.create(  # pyright: ignore[reportAttributeAccessIssue]
+            reward_no=903,
+            title="R3",
+            condition_for_minutes=30,
+            **reward_kwargs,
+        )  # pyright: ignore[reportAttributeAccessIssue]
+
+        with CaptureQueriesContext(connection) as three_campaign_ctx:
+            self.client.get(reverse("chzzk:dashboard"))
+        query_count_three = len(three_campaign_ctx)
+
+        # With prefetch_related, adding more campaigns should not add extra queries per campaign.
+        assert query_count_two == query_count_three
+
     def test_dashboard_view_excludes_testing_state_campaigns(self) -> None:
         """Test that the dashboard view excludes campaigns in the TESTING state."""
         now: datetime = timezone.now()

chzzk/views.py

@@ -34,6 +34,7 @@ def dashboard_view(request: HttpRequest) -> HttpResponse:
         models.ChzzkCampaign.objects
         .filter(end_date__gte=timezone.now())
         .exclude(state="TESTING")
+        .prefetch_related("rewards")
         .order_by("-start_date")
     )
     return render(

config/settings.py

@@ -224,6 +224,10 @@ DATABASES: dict[str, dict[str, Any]] = configure_databases(
     base_dir=BASE_DIR,
 )
 
+if DEBUG:
+    INSTALLED_APPS.append("zeal")
+    MIDDLEWARE.append("zeal.middleware.zeal_middleware")
+
 if not TESTING:
     INSTALLED_APPS = [*INSTALLED_APPS, "debug_toolbar", "silk"]
     MIDDLEWARE = [

kick/models.py

@@ -292,10 +292,19 @@ class KickDropCampaign(auto_prefetch.Model):
     def image_url(self) -> str:
         """Return the image URL for the campaign."""
         # Image from first drop
-        if self.rewards.exists():  # pyright: ignore[reportAttributeAccessIssue]
+        rewards_prefetched: list[KickReward] | None = getattr(
-            first_reward: KickReward | None = self.rewards.first()  # pyright: ignore[reportAttributeAccessIssue]
+            self,
-            if first_reward and first_reward.image_url:
+            "rewards_ordered",
-                return first_reward.full_image_url
+            None,
+        )
+        if rewards_prefetched is not None:
+            first_reward: KickReward | None = (
+                rewards_prefetched[0] if rewards_prefetched else None
+            )
+        else:
+            first_reward = self.rewards.first()  # pyright: ignore[reportAttributeAccessIssue]
+        if first_reward and first_reward.image_url:
+            return first_reward.full_image_url
 
         if self.category and self.category.image_url:
             return self.category.image_url

pyproject.toml

@@ -31,6 +31,7 @@ dependencies = [
     "setproctitle",
     "sitemap-parser",
     "tqdm",
+    "django-zeal>=2.1.0",
 ]
 
 

twitch/views.py

@@ -438,7 +438,13 @@ def drop_campaign_list_view(request: HttpRequest) -> HttpResponse:  # noqa: PLR0
     if game_filter:
         queryset = queryset.filter(game__twitch_id=game_filter)
 
-    queryset = queryset.prefetch_related("game__owners").order_by("-start_at")
+    queryset = queryset.prefetch_related(
+        "game__owners",
+        Prefetch(
+            "time_based_drops",
+            queryset=TimeBasedDrop.objects.prefetch_related("benefits"),
+        ),
+    ).order_by("-start_at")
 
     # Optionally filter by status (active, upcoming, expired)
     now: datetime.datetime = timezone.now()
@@ -588,18 +594,18 @@ def drop_campaign_detail_view(request: HttpRequest, twitch_id: str) -> HttpRespo
                 queryset=Channel.objects.order_by("display_name"),
                 to_attr="channels_ordered",
             ),
+            Prefetch(
+                "time_based_drops",
+                queryset=TimeBasedDrop.objects.prefetch_related("benefits").order_by(
+                    "required_minutes_watched",
+                ),
+            ),
         ).get(twitch_id=twitch_id)
     except DropCampaign.DoesNotExist as exc:
         msg = "No campaign found matching the query"
         raise Http404(msg) from exc
 
-    drops: QuerySet[TimeBasedDrop] = (
+    drops: QuerySet[TimeBasedDrop] = campaign.time_based_drops.all()  # pyright: ignore[reportAttributeAccessIssue]
-        TimeBasedDrop.objects
-        .filter(campaign=campaign)
-        .select_related("campaign")
-        .prefetch_related("benefits")
-        .order_by("required_minutes_watched")
-    )
 
     now: datetime.datetime = timezone.now()
     enhanced_drops: list[dict[str, Any]] = _enhance_drops_with_context(drops, now)