feat: show recommendations in discover page

danjac · Jan 20, 2025 · 71780d5 · 71780d5
1 parent fc01768
commit 71780d5
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Showing 3 changed files with 32 additions and 55 deletions.
diff --git a/radiofeed/podcasts/models.py b/radiofeed/podcasts/models.py
@@ -6,7 +6,7 @@
 from django.contrib.postgres.search import SearchVectorField
 from django.core.validators import MinLengthValidator
 from django.db import models
-from django.db.models.functions import Coalesce, Lower
+from django.db.models.functions import Lower
 from django.urls import reverse
 from django.utils import timezone
 from django.utils.encoding import force_str
@@ -139,42 +139,18 @@ def recommended(self, user: User) -> models.QuerySet["Podcast"]:
         """Returns recommended podcasts for user based on subscriptions. Includes `relevance` annotation.
         Backfills results with promoted podcasts if no recommendations are found.
         """
-
-        # pick highest matches
-        # we want the sum of the relevance of the recommendations, grouped by recommended
-
-        scores = (
-            Recommendation.objects.alias(
-                is_podcast_subscribed=models.Exists(
-                    user.subscriptions.filter(
-                        podcast=models.OuterRef("podcast"),
-                    )
+        return (
+            self.alias(
+                score=models.Sum("similar__score"),
+                relevance=models.Case(
+                    models.When(score__gt=0, then=models.F("score")),
+                    models.When(promoted=True, then=models.Value(1.0)),
+                    default=models.Value(0),
+                    output_field=models.DecimalField(decimal_places=10, max_digits=100),
                 ),
-                is_recommended_subscribed=models.Exists(
-                    user.subscriptions.filter(
-                        podcast=models.OuterRef("recommended"),
-                    )
-                ),
-            )
-            .filter(
-                is_podcast_subscribed=True,
-                is_recommended_subscribed=False,
-                recommended=models.OuterRef("pk"),
             )
-            .values("score")
-            .order_by("-score")
-        )
-
-        return self.annotate(
-            relevance=Coalesce(
-                models.Subquery(
-                    scores.values("score")[:1],
-                ),
-                0,
-                output_field=models.DecimalField(),
-            ),
-        ).filter(
-            models.Q(relevance__gt=0) | models.Q(promoted=True),
+            .exclude(pk__in=user.subscriptions.values("podcast"))
+            .filter(relevance__gt=0)
         )
 
 

diff --git a/radiofeed/podcasts/views.py b/radiofeed/podcasts/views.py
@@ -43,8 +43,11 @@ def discover(request: HttpRequest) -> HttpResponse:
     """Shows all promoted podcasts."""
     podcasts = (
         _get_podcasts()
-        .filter(promoted=True)
-        .order_by("-pub_date")[: settings.DEFAULT_PAGE_SIZE]
+        .recommended(request.user)
+        .order_by(
+            "-relevance",
+            "-pub_date",
+        )[: settings.DEFAULT_PAGE_SIZE]
     )
 
     return render(

diff --git a/templates/podcasts/discover.html b/templates/podcasts/discover.html
@@ -6,22 +6,20 @@
 {% endblock title %}
 
 {% block content %}
-    {% cache 300 discover-podcasts %}
-        <c-header title="Discover">
-            <c-header.nav>
-                <c-header.nav.item>
-                    <c-search.form url="{% url 'podcasts:search_podcasts' %}"
-                                   placeholder="Search: Podcasts"
-                    />
-                </c-header.nav.item>
-            </c-header.nav>
-        </c-header>
-        <c-browse>
-            {% for podcast in podcasts %}
-                <c-browse.item>
-                    <c-podcasts.podcast :podcast="podcast" />
-                </c-browse.item>
-            {% endfor %}
-        </c-browse>
-    {% endcache %}
+    <c-header title="Discover">
+        <c-header.nav>
+            <c-header.nav.item>
+                <c-search.form url="{% url 'podcasts:search_podcasts' %}"
+                               placeholder="Search: Podcasts"
+                />
+            </c-header.nav.item>
+        </c-header.nav>
+    </c-header>
+    <c-browse>
+        {% for podcast in podcasts %}
+            <c-browse.item>
+                <c-podcasts.podcast :podcast="podcast" />
+            </c-browse.item>
+        {% endfor %}
+    </c-browse>
 {% endblock content %}