Add cursor to updates RSS feed.

docs/api-reference/feeds.rst

@@ -21,6 +21,11 @@ Available at https://pypi.org/rss/updates.xml, this feed provides the latest
 newly created releases for individual projects on PyPI, including the project
 name and description, release version, and a link to the release page.
 
+Accepts an optional ``after`` integer cursor, which limits results to the
+releases after the given seconds since the UTC epoch (e.g., the
+``timestamp`` method to a ``datetime.datetime`` object). Note that this changes
+the ordering of the results from newest->oldest to oldest->newest.
+
 
 Project Releases Feed
 ---------------------

tests/unit/rss/test_views.py

@@ -46,6 +46,15 @@ def test_rss_updates(db_request):
     }
     assert db_request.response.content_type == "text/xml"
 
+    after_cursor = datetime.datetime(
+        release1.created.year, release1.created.month, release1.created.day
+    )
+    db_request.params["after"] = after_cursor.timestamp()
+    assert rss.rss_updates(db_request) == {
+        "latest_releases": tuple(zip((release2, release3), ("[email protected]", None)))
+    }
+    assert db_request.response.content_type == "text/xml"
+
 
 def test_rss_packages(db_request):
     db_request.find_service = pretend.call_recorder(

warehouse/rss/views.py

@@ -10,8 +10,10 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+from datetime import datetime
 from email.utils import getaddresses
 
+from pyramid.httpexceptions import HTTPBadRequest
 from pyramid.view import view_config
 from sqlalchemy.orm import joinedload
 
@@ -59,17 +61,34 @@ def _format_author(release):
     ],
 )
 def rss_updates(request):
+
+    after_timestamp = request.params.get("after")
+    if after_timestamp:
+        try:
+            after_timestamp = datetime.utcfromtimestamp(int(after_timestamp))
+        except ValueError:
+            raise HTTPBadRequest("'after' must be an integer") from None
+        latest_releases = (
+            request.db.query(Release)
+            .options(joinedload(Release.project))
+            .filter(Release.created > after_timestamp)
+            .order_by(Release.created.asc())
+            .limit(100)
+            .all()
+        )
+    else:
+        latest_releases = (
+            request.db.query(Release)
+            .options(joinedload(Release.project))
+            .order_by(Release.created.desc())
+            .limit(100)
+            .all()
+        )
+
     request.response.content_type = "text/xml"
 
     request.find_service(name="csp").merge(XML_CSP)
 
-    latest_releases = (
-        request.db.query(Release)
-        .options(joinedload(Release.project))
-        .order_by(Release.created.desc())
-        .limit(40)
-        .all()
-    )
     release_authors = [_format_author(release) for release in latest_releases]
 
     return {"latest_releases": tuple(zip(latest_releases, release_authors))}