added builtin support for multiple stylesheets

django/contrib/syndication/views.py

@@ -160,7 +160,7 @@ def get_feed(self, obj, request):
             feed_copyright=self._get_dynamic_attr("feed_copyright", obj),
             feed_guid=self._get_dynamic_attr("feed_guid", obj),
             ttl=self._get_dynamic_attr("ttl", obj),
-            stylesheet=self._get_dynamic_attr("stylesheet", obj),
+            stylesheets=self._get_dynamic_attr("stylesheets", obj),
             **self.feed_extra_kwargs(obj),
         )
 

django/utils/feedgenerator.py

@@ -123,20 +123,24 @@ def __init__(
         feed_copyright=None,
         feed_guid=None,
         ttl=None,
-        stylesheet=None,
+        stylesheets=None,
         **kwargs,
     ):
         def to_str(s):
             return str(s) if s is not None else s
 
         def to_stylesheet(s):
-            if s is None:
-                return None
-            if isinstance(s, Stylesheet):
-                return s
-            return Stylesheet(s)
+            return s if isinstance(s, Stylesheet) else Stylesheet(s)
 
         categories = categories and [str(c) for c in categories]
+
+        if stylesheets is None:
+            pass
+        elif isinstance(stylesheets, (list, tuple)):
+            stylesheets = [to_stylesheet(s) for s in stylesheets]
+        else:
+            stylesheets = [to_stylesheet(stylesheets)]
+
         self.feed = {
             "title": to_str(title),
             "link": iri_to_uri(link),
@@ -151,7 +155,7 @@ def to_stylesheet(s):
             "feed_copyright": to_str(feed_copyright),
             "id": feed_guid or link,
             "ttl": to_str(ttl),
-            "stylesheet": to_stylesheet(stylesheet),
+            "stylesheets": stylesheets,
             **kwargs,
         }
         self.items = []
@@ -314,7 +318,7 @@ def write_items(self, handler):
             handler.endElement("item")
 
     def add_stylesheets(self, handler):
-        if (stylesheet := self.feed["stylesheet"]) is not None:
+        for stylesheet in self.feed["stylesheets"] or []:
             handler.processingInstruction("xml-stylesheet", stylesheet)
 
     def add_root_elements(self, handler):

docs/ref/contrib/syndication.txt

@@ -596,23 +596,29 @@ This example illustrates all possible attributes and methods for a
 
         ttl = 600  # Hard-coded Time To Live.
 
-        # STYLESHEET -- One of the following three is optional. The framework
-        # looks for them in this order.
+        # STYLESHEETS -- Optional. To set, provide one of the following three.
+        # The framework looks for them in this order.
 
-        def stylesheet(self, obj):
+        def stylesheets(self, obj):
             """
             Takes the object returned by get_object() and returns the feed's
-            stylesheet (an URL string or a Stylesheet instance).
+            stylesheets (an URL string or a Stylesheet instance).
             """
 
-        def stylesheet(self):
+        def stylesheets(self):
             """
             Returns the feed's stylesheet (an URL string or a Stylesheet
             instance).
             """
 
-        stylesheet = "/link/to/stylesheet.xsl"
-        stylesheet = feedgenerator.Stylesheet("/link/to/stylesheet.xsl")
+        # Hardcoded stylesheets (can be a single stylesheet or a list)
+        stylesheets = "/link/to/stylesheet.xsl"
+        stylesheets = feedgenerator.Stylesheet("/link/to/stylesheet.xsl")
+        stylesheets = ["/stylesheet1.xsl", "stylesheet2.xls"]
+        stylesheets = [
+            feedgenerator.Stylesheet("/stylesheet1.xsl"),
+            feedgenerator.Stylesheet("/stylesheet2.xsl"),
+        ]
 
         # ITEMS -- One of the following three is required. The framework looks
         # for them in this order.
@@ -979,15 +985,21 @@ They share this interface:
     * ``feed_copyright``
     * ``feed_guid``
     * ``ttl``
-    * ``stylesheet``
+    * ``stylesheets``
 
     Any extra keyword arguments you pass to ``__init__`` will be stored in
     ``self.feed`` for use with `custom feed generators`_.
 
-    All parameters should be strings, except ``categories``, which should be a
-    sequence of strings. Beware that some control characters
-    are `not allowed <https://www.w3.org/International/questions/qa-controls>`_
-    in XML documents. If your content has some of them, you might encounter a
+    All parameters should be strings, except for two:
+
+        - ``categories`` should be a sequence of strings.
+        - ``stylesheets`` can be a single string, an instance of
+        :class:`~django.utils.feedgenerator.Stylesheets`, or a list of either
+        strings or ``Stylesheet`` instances.
+
+    Beware that some control characters are
+    `not allowed <https://www.w3.org/International/questions/qa-controls>`_ in
+    XML documents. If your content has some of them, you might encounter a
     :exc:`ValueError` when producing the feed.
 
 :meth:`.SyndicationFeed.add_item`
@@ -1121,7 +1133,7 @@ Feed stylesheets
 .. versionadded:: 5.1
 
 You can add styling to your RSS feed using a stylesheet (typically in the XSLT_
-or CSS formats) by setting the ``stylesheet`` attribute on the feed class.
+or CSS formats) by setting the ``stylesheets`` attribute on the feed class.
 
 This can be a hardcoded URL::
 
@@ -1130,7 +1142,7 @@ This can be a hardcoded URL::
 
     class FeedWithHardcodedStylesheet(Feed):
         ...  # author, etc.
-        stylesheet = "https://example.com/rss_stylesheet.xslt"
+        stylesheets = "https://example.com/rss_stylesheet.xslt"
 
 You can also use Django's static files system::
 
@@ -1140,7 +1152,7 @@ You can also use Django's static files system::
 
     class FeedWithStaticFileStylesheet(Feed):
         ...  # author, etc.
-        stylesheet = static("rss_styles.xslt")
+        stylesheets = static("rss_styles.xslt")
 
 Another option is to have a view in your project that renders the XSLT document.
 You can then link it like so::
@@ -1151,7 +1163,7 @@ You can then link it like so::
 
     class FeedWithStylesheetView(Feed):
         ...  # author, etc.
-        stylesheet = reverse_lazy("your-custom-view-name")
+        stylesheets = reverse_lazy("your-custom-view-name")
 
 Django will normally try to guess the MIME type of the given URL based on its
 extension, but if that fails you can specify it using the
@@ -1163,7 +1175,7 @@ extension, but if that fails you can specify it using the
 
     class FeedWithHardcodedStylesheet(Feed):
         ...  # author, etc.
-        stylesheet = Stylesheet("https://example.com/rss_stylesheet", mimetype="text/xsl")
+        stylesheets = Stylesheet("https://example.com/rss_stylesheet", mimetype="text/xsl")
 
 Similarly, if you'd like to use a different ``media`` attribute than ``screen``
 (Django's default), you can use the
@@ -1175,6 +1187,20 @@ Similarly, if you'd like to use a different ``media`` attribute than ``screen``
 
     class FeedWithHardcodedStylesheet(Feed):
         ...  # author, etc.
-        stylesheet = Stylesheet("https://example.com/rss_stylesheet.xslt", media="print")
+        stylesheets = Stylesheet("https://example.com/rss_stylesheet.xslt", media="print")
+
+Finally, if you need support for multiple stylesheets you can pass a list of
+stylesheets (either as strings or as ``Stylesheet`` objects as shown above)::
+
+    from django.contrib.syndication.views import Feed
+    from django.utils.feedgenerator import Stylesheet
+
+
+    class MultiStylesheetFeed(Feed):
+        ...  # author, etc.
+        stylesheets = [
+            "/stylesheet1.xsl",
+            Stylesheet("/stylesheet2.xsl"),
+        ]
 
 .. _xslt: https://developer.mozilla.org/en-US/docs/Web/XSLT/Transforming_XML_with_XSLT

docs/ref/utils.txt

@@ -336,21 +336,25 @@ https://web.archive.org/web/20110718035220/http://diveintomark.org/archives/2004
 
 .. versionadded:: 5.1
 
-.. class:: Stylesheet
+.. class:: Stylesheet(url, mimetype="", media="screen")
 
     Represents an RSS stylesheet
 
-    .. method:: __init__(url, mimetype, media="screen")
+    .. attribute:: url
 
-        ``url`` is the URL of the stylesheet. This argument is required.
+        Required argument. The URL where the stylesheet is located.
 
-        ``mimetype`` is the MIME type of the stylesheet. This argument is
-        optional. If not provided, Django will attempt to guess it by using
-        Python's :py:func:`mimetypes.guess_type()`. Use ``mimetype=None`` if you don't
+    .. attribute:: mimetype
+
+        An optional string containing the MIME type of the stylesheet. If not
+        specified, Django will attempt to guess it by using Python's
+        :py:func:`mimetypes.guess_type()`. Use ``mimetype=None`` if you don't
         want your stylesheet to have a MIME type specified.
 
-        ``media`` will be used as the ``media`` attribute of the stylesheet.
-        Django uses ``media="screen"`` by default. Use ``media=None`` if you
+    .. attribute:: media
+
+        An optional string which will be used as the ``media`` attribute of
+        the stylesheet. Defaults to ``"screen"`. Use ``media=None`` if you
         don't want your stylesheet to have a ``media`` attribute.
 
 ``SyndicationFeed``
@@ -361,21 +365,24 @@ https://web.archive.org/web/20110718035220/http://diveintomark.org/archives/2004
     Base class for all syndication feeds. Subclasses should provide
     ``write()``.
 
-    .. method:: __init__(title, link, description, language=None, author_email=None, author_name=None, author_link=None, subtitle=None, categories=None, feed_url=None, feed_copyright=None, feed_guid=None, ttl=None, stylesheet=None, **kwargs)
+    .. method:: __init__(title, link, description, language=None, author_email=None, author_name=None, author_link=None, subtitle=None, categories=None, feed_url=None, feed_copyright=None, feed_guid=None, ttl=None, stylesheets=None, **kwargs)
 
         Initialize the feed with the given dictionary of metadata, which applies
         to the entire feed.
 
         Any extra keyword arguments you pass to ``__init__`` will be stored in
         ``self.feed``.
 
-        All parameters should be strings, except ``categories``, which should
-        be a sequence of strings. The ``stylesheet`` argument can be a string
-        or an instance of :class:`Stylesheet`.
+        All parameters should be strings, except for two:
+
+            - ``categories`` should be a sequence of strings.
+            - ``stylesheets`` can be a single string, an instance of
+            :class:`Stylesheets`, or a list of either strings or ``Stylesheet``
+            instances.
 
         .. versionchanged:: 5.1
 
-            The ``stylesheet`` argument was added.
+            The ``stylesheets`` argument was added.
 
     .. method:: add_item(title, link, description, author_email=None, author_name=None, author_link=None, pubdate=None, comments=None, unique_id=None, categories=(), item_copyright=None, ttl=None, updateddate=None, enclosures=None, **kwargs)
 

tests/syndication_tests/feeds.py

@@ -237,7 +237,14 @@ def item_title(self, item):
 
 
 class TestFeedWithStylesheet(TestRss2Feed):
-    stylesheet = "/stylesheet.xsl"
+    stylesheets = "/stylesheet.xsl"
+
+
+class TestFeedWithMultipleStylesheets(TestRss2Feed):
+    stylesheets = [
+        "/stylesheet1.xsl",
+        feedgenerator.Stylesheet("/stylesheet2.xsl"),
+    ]
 
 
 class NaiveDatesFeed(TestAtomFeed):

tests/syndication_tests/tests.py

@@ -569,7 +569,7 @@ def test_stylesheet_none(self):
             title="test",
             link="https://example.com",
             description="test",
-            stylesheet=None,
+            stylesheets=None,
         )
         self.assertNotIn("xml-stylesheet", feed.writeString("utf-8"))
 
@@ -623,12 +623,18 @@ def test_stylesheet(self):
                 'href="/test.xsl" type="text/xml" media="screen"',
             ),
         ]
-        for stylesheet, expected in testdata:
+        # any accepted single argument should also be accepted when in a list/tuple
+        testdata = (
+            testdata
+            + [([s], expected) for s, expected in testdata]
+            + [((s,), expected) for s, expected in testdata]
+        )
+        for stylesheets, expected in testdata:
             feed = Rss201rev2Feed(
                 title="test",
                 link="https://example.com",
                 description="test",
-                stylesheet=stylesheet,
+                stylesheets=stylesheets,
             )
             doc = feed.writeString("utf-8")
             with self.subTest(expected=expected):
@@ -643,6 +649,20 @@ def test_stylesheet_instruction_is_at_the_top(self):
             'href="/stylesheet.xsl" type="text/xsl" media="screen"',
         )
 
+    def test_multiple_stylesheets(self):
+        response = self.client.get("/syndication/stylesheet/multi/")
+        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"',
+        )
+
     @requires_tz_support
     def test_feed_last_modified_time_naive_date(self):
         """

tests/syndication_tests/urls.py

@@ -37,6 +37,7 @@
     path("syndication/template/", feeds.TemplateFeed()),
     path("syndication/template_context/", feeds.TemplateContextFeed()),
     path("syndication/stylesheet/", feeds.TestFeedWithStylesheet()),
+    path("syndication/stylesheet/multi/", feeds.TestFeedWithMultipleStylesheets()),
     path("syndication/rss2/single-enclosure/", feeds.TestSingleEnclosureRSSFeed()),
     path("syndication/rss2/multiple-enclosure/", feeds.TestMultipleEnclosureRSSFeed()),
     path("syndication/atom/single-enclosure/", feeds.TestSingleEnclosureAtomFeed()),