Fixed #13110 -- Added support for multiple enclosures in Atom feeds.

The ``item_enclosures`` hook returns a list of ``Enclosure`` objects which is
then used by the feed builder. If the feed is a RSS feed, an exception is
raised as RSS feeds don't allow multiple enclosures per feed item.

The ``item_enclosures`` hook defaults to an empty list or, if the
``item_enclosure_url`` hook is defined, to a list with a single ``Enclosure``
built from the ``item_enclosure_url``, ``item_enclosure_length``, and
``item_enclosure_mime_type`` hooks.

2 files changed, 50 insertions, 24 deletions

diff --git a/django/contrib/syndication/views.py b/django/contrib/syndication/views.py
index 7bcc951611..2e5e5f3ef9 100644
--- a/django/contrib/syndication/views.py
+++ b/django/contrib/syndication/views.py
@@ -64,6 +64,17 @@ class Feed(object):
                 'item_link() method in your Feed class.' % item.__class__.__name__
             )
 
+    def item_enclosures(self, item):
+        enc_url = self.__get_dynamic_attr('item_enclosure_url', item)
+        if enc_url:
+            enc = feedgenerator.Enclosure(
+                url=smart_text(enc_url),
+                length=smart_text(self.__get_dynamic_attr('item_enclosure_length', item)),
+                mime_type=smart_text(self.__get_dynamic_attr('item_enclosure_mime_type', item)),
+            )
+            return [enc]
+        return []
+
     def __get_dynamic_attr(self, attname, obj, default=None):
         try:
             attr = getattr(self, attname)
@@ -171,14 +182,7 @@ class Feed(object):
                 self.__get_dynamic_attr('item_link', item),
                 request.is_secure(),
             )
-            enc = None
-            enc_url = self.__get_dynamic_attr('item_enclosure_url', item)
-            if enc_url:
-                enc = feedgenerator.Enclosure(
-                    url=smart_text(enc_url),
-                    length=smart_text(self.__get_dynamic_attr('item_enclosure_length', item)),
-                    mime_type=smart_text(self.__get_dynamic_attr('item_enclosure_mime_type', item))
-                )
+            enclosures = self.__get_dynamic_attr('item_enclosures', item)
             author_name = self.__get_dynamic_attr('item_author_name', item)
             if author_name is not None:
                 author_email = self.__get_dynamic_attr('item_author_email', item)
@@ -203,7 +207,7 @@ class Feed(object):
                 unique_id=self.__get_dynamic_attr('item_guid', item, link),
                 unique_id_is_permalink=self.__get_dynamic_attr(
                     'item_guid_is_permalink', item),
-                enclosure=enc,
+                enclosures=enclosures,
                 pubdate=pubdate,
                 updateddate=updateddate,
                 author_name=author_name,
diff --git a/django/utils/feedgenerator.py b/django/utils/feedgenerator.py
index 9b1421160b..c67fedb277 100644
--- a/django/utils/feedgenerator.py
+++ b/django/utils/feedgenerator.py
@@ -118,11 +118,13 @@ class SyndicationFeed(object):
     def add_item(self, title, link, description, author_email=None,
             author_name=None, author_link=None, pubdate=None, comments=None,
             unique_id=None, unique_id_is_permalink=None, enclosure=None,
-            categories=(), item_copyright=None, ttl=None, updateddate=None, **kwargs):
+            categories=(), item_copyright=None, ttl=None, updateddate=None,
+            enclosures=None, **kwargs):
         """
         Adds an item to the feed. All args are expected to be Python Unicode
         objects except pubdate and updateddate, which are datetime.datetime
-        objects, and enclosure, which is an instance of the Enclosure class.
+        objects, and enclosures, which is an iterable of instances of the
+        Enclosure class.
         """
         to_unicode = lambda s: force_text(s, strings_only=True)
         if categories:
@@ -130,6 +132,16 @@ class SyndicationFeed(object):
         if ttl is not None:
             # Force ints to unicode
             ttl = force_text(ttl)
+        if enclosure is None:
+            enclosures = [] if enclosures is None else enclosures
+        else:
+            warnings.warn(
+                "The enclosure keyword argument is deprecated, "
+                "use enclosures instead.",
+                RemovedInDjango20Warning,
+                stacklevel=2,
+            )
+            enclosures = [enclosure]
         item = {
             'title': to_unicode(title),
             'link': iri_to_uri(link),
@@ -142,7 +154,7 @@ class SyndicationFeed(object):
             'comments': to_unicode(comments),
             'unique_id': to_unicode(unique_id),
             'unique_id_is_permalink': unique_id_is_permalink,
-            'enclosure': enclosure,
+            'enclosures': enclosures,
             'categories': categories or (),
             'item_copyright': to_unicode(item_copyright),
             'ttl': ttl,
@@ -317,10 +329,19 @@ class Rss201rev2Feed(RssFeed):
             handler.addQuickElement("ttl", item['ttl'])
 
         # Enclosure.
-        if item['enclosure'] is not None:
-            handler.addQuickElement("enclosure", '',
-                {"url": item['enclosure'].url, "length": item['enclosure'].length,
-                    "type": item['enclosure'].mime_type})
+        if item['enclosures']:
+            enclosures = list(item['enclosures'])
+            if len(enclosures) > 1:
+                raise ValueError(
+                    "RSS feed items may only have one enclosure, see "
+                    "http://www.rssboard.org/rss-profile#element-channel-item-enclosure"
+                )
+            enclosure = enclosures[0]
+            handler.addQuickElement('enclosure', '', {
+                'url': enclosure.url,
+                'length': enclosure.length,
+                'type': enclosure.mime_type,
+            })
 
         # Categories.
         for cat in item['categories']:
@@ -328,7 +349,7 @@ class Rss201rev2Feed(RssFeed):
 
 
 class Atom1Feed(SyndicationFeed):
-    # Spec: http://atompub.org/2005/07/11/draft-ietf-atompub-format-10.html
+    # Spec: https://tools.ietf.org/html/rfc4287
     content_type = 'application/atom+xml; charset=utf-8'
     ns = "http://www.w3.org/2005/Atom"
 
@@ -405,13 +426,14 @@ class Atom1Feed(SyndicationFeed):
         if item['description'] is not None:
             handler.addQuickElement("summary", item['description'], {"type": "html"})
 
-        # Enclosure.
-        if item['enclosure'] is not None:
-            handler.addQuickElement("link", '',
-                {"rel": "enclosure",
-                 "href": item['enclosure'].url,
-                 "length": item['enclosure'].length,
-                 "type": item['enclosure'].mime_type})
+        # Enclosures.
+        for enclosure in item.get('enclosures') or []:
+            handler.addQuickElement('link', '', {
+                'rel': 'enclosure',
+                'href': enclosure.url,
+                'length': enclosure.length,
+                'type': enclosure.mime_type,
+            })
 
         # Categories.
         for cat in item['categories']: