Fixed #12978 -- Added support for RSS feed stylesheets.

tests/syndication_tests/feeds.py

@@ -236,6 +236,13 @@ class TestGetObjectFeed(TestRss2Feed):
         return "Title: %s" % item.title
 
 
+class TestFeedWithStylesheets(TestRss2Feed):
+    stylesheets = [
+        "/stylesheet1.xsl",
+        feedgenerator.Stylesheet("/stylesheet2.xsl"),
+    ]
+
+
 class NaiveDatesFeed(TestAtomFeed):
     """
     A feed with naive (non-timezone-aware) dates.

tests/syndication_tests/tests.py

@@ -4,12 +4,16 @@ from xml.dom import minidom
 from django.contrib.sites.models import Site
 from django.contrib.syndication import views
 from django.core.exceptions import ImproperlyConfigured
+from django.templatetags.static import static
 from django.test import TestCase, override_settings
 from django.test.utils import requires_tz_support
+from django.urls import reverse, reverse_lazy
 from django.utils import timezone
 from django.utils.feedgenerator import (
     Atom1Feed,
     Rss201rev2Feed,
+    Stylesheet,
+    SyndicationFeed,
     rfc2822_date,
     rfc3339_date,
 )
@@ -561,6 +565,125 @@ class SyndicationFeedTest(FeedTestCase):
                 doc = feed.writeString("utf-8")
                 self.assertIn(f'<{tag} href="https://feed.url.com" rel="self"/>', doc)
 
+    def test_stylesheets_none(self):
+        feed = Rss201rev2Feed(
+            title="test",
+            link="https://example.com",
+            description="test",
+            stylesheets=None,
+        )
+        self.assertNotIn("xml-stylesheet", feed.writeString("utf-8"))
+
+    def test_stylesheets(self):
+        testdata = [
+            # Plain strings.
+            ("/test.xsl", 'href="/test.xsl" type="text/xsl" media="screen"'),
+            ("/test.xslt", 'href="/test.xslt" type="text/xsl" media="screen"'),
+            ("/test.css", 'href="/test.css" type="text/css" media="screen"'),
+            ("/test", 'href="/test" media="screen"'),
+            (
+                "https://example.com/test.xsl",
+                'href="https://example.com/test.xsl" type="text/xsl" media="screen"',
+            ),
+            (
+                "https://example.com/test.css",
+                'href="https://example.com/test.css" type="text/css" media="screen"',
+            ),
+            (
+                "https://example.com/test",
+                'href="https://example.com/test" media="screen"',
+            ),
+            ("/♥.xsl", 'href="/%E2%99%A5.xsl" type="text/xsl" media="screen"'),
+            (
+                static("stylesheet.xsl"),
+                'href="/static/stylesheet.xsl" type="text/xsl" media="screen"',
+            ),
+            (
+                static("stylesheet.css"),
+                'href="/static/stylesheet.css" type="text/css" media="screen"',
+            ),
+            (static("stylesheet"), 'href="/static/stylesheet" media="screen"'),
+            (
+                reverse("syndication-xsl-stylesheet"),
+                'href="/syndication/stylesheet.xsl" type="text/xsl" media="screen"',
+            ),
+            (
+                reverse_lazy("syndication-xsl-stylesheet"),
+                'href="/syndication/stylesheet.xsl" type="text/xsl" media="screen"',
+            ),
+            # Stylesheet objects.
+            (
+                Stylesheet("/test.xsl"),
+                'href="/test.xsl" type="text/xsl" media="screen"',
+            ),
+            (Stylesheet("/test.xsl", mimetype=None), 'href="/test.xsl" media="screen"'),
+            (Stylesheet("/test.xsl", media=None), 'href="/test.xsl" type="text/xsl"'),
+            (Stylesheet("/test.xsl", mimetype=None, media=None), 'href="/test.xsl"'),
+            (
+                Stylesheet("/test.xsl", mimetype="text/xml"),
+                'href="/test.xsl" type="text/xml" media="screen"',
+            ),
+        ]
+        for stylesheet, expected in testdata:
+            feed = Rss201rev2Feed(
+                title="test",
+                link="https://example.com",
+                description="test",
+                stylesheets=[stylesheet],
+            )
+            doc = feed.writeString("utf-8")
+            with self.subTest(expected=expected):
+                self.assertIn(f"<?xml-stylesheet {expected}?>", doc)
+
+    def test_stylesheets_instructions_are_at_the_top(self):
+        response = self.client.get("/syndication/stylesheet/")
+        doc = minidom.parseString(response.content)
+        self.assertEqual(doc.childNodes[0].nodeName, "xml-stylesheet")
+        self.assertEqual(
+            doc.childNodes[0].data,
+            'href="/stylesheet1.xsl" type="text/xsl" media="screen"',
+        )
+        self.assertEqual(doc.childNodes[1].nodeName, "xml-stylesheet")
+        self.assertEqual(
+            doc.childNodes[1].data,
+            'href="/stylesheet2.xsl" type="text/xsl" media="screen"',
+        )
+
+    def test_stylesheets_typeerror_if_str_or_stylesheet(self):
+        for stylesheet, error_message in [
+            ("/stylesheet.xsl", "stylesheets should be a list, not <class 'str'>"),
+            (
+                Stylesheet("/stylesheet.xsl"),
+                "stylesheets should be a list, "
+                "not <class 'django.utils.feedgenerator.Stylesheet'>",
+            ),
+        ]:
+            args = ("title", "/link", "description")
+            with self.subTest(stylesheets=stylesheet):
+                self.assertRaisesMessage(
+                    TypeError,
+                    error_message,
+                    SyndicationFeed,
+                    *args,
+                    stylesheets=stylesheet,
+                )
+
+    def test_stylesheets_repr(self):
+        testdata = [
+            (Stylesheet("/test.xsl", mimetype=None), "('/test.xsl', None, 'screen')"),
+            (Stylesheet("/test.xsl", media=None), "('/test.xsl', 'text/xsl', None)"),
+            (
+                Stylesheet("/test.xsl", mimetype=None, media=None),
+                "('/test.xsl', None, None)",
+            ),
+            (
+                Stylesheet("/test.xsl", mimetype="text/xml"),
+                "('/test.xsl', 'text/xml', 'screen')",
+            ),
+        ]
+        for stylesheet, expected in testdata:
+            self.assertEqual(repr(stylesheet), expected)
+
     @requires_tz_support
     def test_feed_last_modified_time_naive_date(self):
         """

tests/syndication_tests/urls.py

@@ -36,8 +36,14 @@ urlpatterns = [
     path("syndication/articles/", feeds.ArticlesFeed()),
     path("syndication/template/", feeds.TemplateFeed()),
     path("syndication/template_context/", feeds.TemplateContextFeed()),
+    path("syndication/stylesheet/", feeds.TestFeedWithStylesheets()),
     path("syndication/rss2/single-enclosure/", feeds.TestSingleEnclosureRSSFeed()),
     path("syndication/rss2/multiple-enclosure/", feeds.TestMultipleEnclosureRSSFeed()),
     path("syndication/atom/single-enclosure/", feeds.TestSingleEnclosureAtomFeed()),
     path("syndication/atom/multiple-enclosure/", feeds.TestMultipleEnclosureAtomFeed()),
+    path(
+        "syndication/stylesheet.xsl",
+        lambda request: None,
+        name="syndication-xsl-stylesheet",
+    ),
 ]