My latest WordPress extension adds support for feed delta updates to feeds generated by WordPress. Delta updates is a more bandwidth efficient way of delivering feed updates to subscribers that removes feed entries already fetched by the client.
You can download the Delta Feed Updates plugin from the WordPress Plugin Directory.
The sets the appropriate HTTP response headers and reacts to delta update request headers, as described in my earlier piece on feed delta updates. All the appropriate caching headers are also taken care of.
Technically speaking, the plugin rewrites the main WP_Query when feed readers pull your feeds to insert a WP_Date_Query that corresponds to the date of the last feed update as communicated through the request headers. Feed entries published since the last pull date, along with entries that have been published in the last seven days that have been modified since the last pull. The timestamps are normalized somewhat to improve SQL query caching.
You can download the Feed Delta Updates plugin from the WordPress Plugin Directory. No configuration is required: install, activate, and you’ve begun distributing delta updates to your feeds.
You can improve your feed delivery further by combining the Feed Delta Updates plugin with some of my other WordPress plugins:
- The Minor Edits plugin can reduce the number of feed entries that are pushed out for insignificant edits to already published entries. (Required to be fully compliant with the Atom syndication standard.)
- The Cache-Control plugin lets you specify the max-age (client caches) and s-maxage (shared caches) of the Cache-Control header for all types of feeds and pages in WordPress. This can be especially useful to configure the caching of a WordPress instance that’s delivered via a reverse-proxy or another HTTP caching mechanism.
The Feed Delta Updates plugin for WordPress is licensed under a GNU GPLv3 license; see the plugin page for details. WordPress and the WordPress circled-W logo are trademarks of WordPress Foundation.