Custom Feeds in WordPress

There are many reason’s you might need to create a custom feed in WordPress. You may need a feed in an unusual or non-standard format, or you may want to add or edit the content of your feeds. Setting up a custom feed is pretty easy, but poorly documented.

Everything revolves around the add_feed function. This function takes two arguments: a name for your feed and a function to call to create the feed:

add_feed('myFeed', 'myPlugin_create_feed');

The function from the latter argument will handle all of the work of creating your feed. It will have access to the WordPress loop, so after calling have_posts() and the_post(), you can take advantage of all the template tags available.

When to call add_feed

For add_feed to work, you have to wait until WordPress has completely initialized before you call it. You can use the init action hook to accomplish this at the right time.

add_action('init', 'myPlugin_add_feed');
 
function myPlugin_add_feed(  ) {
  add_feed('myFeed', 'myPlugin_create_feed');
}

Changing Rewrite Rules

If you stopped there, WordPress would call myPlugin_create_feed() whenever you go to a page and add the query string feed=myFeed to the end of the URL. Example: http://example.com/?feed=myFeed or http://example.com/?s=foo&feed=myFeed.

If you want to make the URL for your feed look like the other feeds in WordPress (e.g., http://example.com/feed/atom), you have to change the rewrite rules.

To tell WordPress to add new rules, use the generate_rewrite_rules action hook. It will call your function just before it finishes building its rules, with the $wp_rewrite object as an argument. Simply add your new rule to the pre-existing $wp_rewrite->rules array.

function myPlugin_rewrite_rules( $wp_rewrite ) {
  $new_rules = array(
    'feed/(.+)' => 'index.php?feed='.$wp_rewrite->preg_index(1)
  );
  $wp_rewrite->rules = $new_rules + $wp_rewrite->rules;
}

You can add this action hook into your myPlugin_add_feedfunction. Finally, you need to tell WordPress to rebuild its rewrite rules now that it has your additions, using $wp_rewrite->flush_rules().

function myPlugin_add_feed(  ) {
  global $wp_rewrite;
  add_feed('myFeed', 'myPlugin_create_feed');
  add_action('generate_rewrite_rules', 'myPlugin_rewrite_rules');
  $wp_rewrite->flush_rules();
}

Now your customized feed should be accessible at http://example.com/feed/myFeed.

jQuery and Ajax in WordPress Plugins – Public Pages

My previous post teaches you how to use jQuery and Ajax for the administration pages in your WordPress plugins. To use them in your user-facing pages requires a few changes.

We’ll use here a simlarly contrived example. Let’s say you use <!--more--> in your longer posts so they don’t fill up too much of your page. Normally, clicking the “Read more…” (or whatever text you use) link takes the user to a separate page with the complete post. In our example, rather than sending the reader to a new page, we’ll make an Ajax request to get the rest of the post and insert it directly into the current page. Continue reading “jQuery and Ajax in WordPress Plugins – Public Pages”