feat(#1612): add rss feed for latest downloads (#2569)

* feat: add rss feed for latest downloads

* Update downloads/views.py

* fix:  query DB for releas

* fix: query DB for releas

* chore: add missing types

* fix: update naive datetime, remove staticmethod

* fix: remove staticmethod

chore: apply formatting and ruuuuuff

* chore: no logging needed after working

* tests: add them

* chore: address code reviews

* chore: remove unused imports

* chore: remove unused code

* chore: remove unused code

* fix: purge cdn cache

* revert: put the code back, john

Author: JacobCoffee

downloads/models.py

@@ -272,6 +272,7 @@ def purge_fastly_download_pages(sender, instance, **kwargs):
     if instance.is_published:
         # Purge our common pages
         purge_url('/downloads/')
+        purge_url('/downloads/feed.rss')
         purge_url('/downloads/latest/python2/')
         purge_url('/downloads/latest/python3/')
         purge_url('/downloads/macos/')

downloads/tests/test_views.py

@@ -554,3 +554,45 @@ def test_filter_release_file_delete_by_release(self):
             headers={"authorization": self.Authorization}
         )
         self.assertEqual(response.status_code, 405)
+
+class ReleaseFeedTests(BaseDownloadTests):
+    """Tests for the downloads/feed.rss endpoint.
+
+    Content is ensured via setUp in BaseDownloadTests.
+    """
+
+    url = reverse("downloads:feed")
+
+
+    def test_endpoint_reachable(self) -> None:
+        response = self.client.get(self.url)
+        self.assertEqual(response.status_code, 200)
+
+    def test_feed_content(self) -> None:
+        """Ensure feed content is as expected.
+
+        Some things we want to check:
+         - Feed title, description, pubdate
+         - Feed items (releases) are in the correct order
+         - We get the expected number of releases (10)
+        """
+        response = self.client.get(self.url)
+        content = response.content.decode()
+
+        self.assertIn("Python 2.7.5", content)
+        self.assertIn("Python 3.10", content)
+        # Published but hidden show up in the API and thus the feed
+        self.assertIn("Python 0.0.0", content)
+
+        # No unpublished releases
+        self.assertNotIn("Python 9.7.2", content)
+
+        # Pre-releases are shown
+        self.assertIn("Python 3.9.90", content)
+
+    def test_feed_item_count(self) -> None:
+        response = self.client.get(self.url)
+        content = response.content.decode()
+
+        # In BaseDownloadTests, we create 5 releases, 4 of which are published, 1 of those published are hidden..
+        self.assertEqual(content.count("<item>"), 4)

downloads/urls.py

@@ -9,4 +9,5 @@
     path('release/<slug:release_slug>/', views.DownloadReleaseDetail.as_view(), name='download_release_detail'),
     path('<slug:slug>/', views.DownloadOSList.as_view(), name='download_os_list'),
     path('', views.DownloadHome.as_view(), name='download'),
+    path("feed.rss", views.ReleaseFeed(), name="feed"),
 ]

downloads/views.py

@@ -1,7 +1,14 @@
+from typing import Any
+
+from datetime import datetime
+
 from django.db.models import Prefetch
 from django.urls import reverse
+from django.utils import timezone
 from django.views.generic import DetailView, TemplateView, ListView, RedirectView
 from django.http import Http404
+from django.contrib.syndication.views import Feed
+from django.utils.feedgenerator import Rss201rev2Feed
 
 from .models import OS, Release, ReleaseFile
 
@@ -147,3 +154,45 @@ def get_context_data(self, **kwargs):
         )
 
         return context
+
+
+class ReleaseFeed(Feed):
+    """Generate an RSS feed of the latest Python releases.
+
+    .. note:: It may seem like these are unused methods, but the superclass uses them
+        using Django's Syndication framework.
+        Docs: https://docs.djangoproject.com/en/4.2/ref/contrib/syndication/
+    """
+
+    feed_type = Rss201rev2Feed
+    title = "Python Releases"
+    description = "Latest Python releases from Python.org"
+
+    @staticmethod
+    def link() -> str:
+        """Return the URL to the main downloads page."""
+        return reverse("downloads:download")
+
+    def items(self) -> list[dict[str, Any]]:
+        """Return the latest Python releases."""
+        return Release.objects.filter(is_published=True).order_by("-release_date")[:10]
+
+    def item_title(self, item: Release) -> str:
+        """Return the release name as the item title."""
+        return item.name
+
+    def item_description(self, item: Release) -> str:
+        """Return the release version and release date as the item description."""
+        return f"Version: {item.version}, Release Date: {item.release_date}"
+
+    def item_pubdate(self, item: Release) -> datetime | None:
+        """Return the release date as the item publication date."""
+        if item.release_date:
+            if timezone.is_naive(item.release_date):
+                return timezone.make_aware(item.release_date)
+            return item.release_date
+        return None
+
+    def item_guid(self, item: Release) -> str:
+        """Return a unique ID for the item based on DB record."""
+        return str(item.pk)