对于基础知识，我遵循了我在Google上找到的以下指南：

• http://www.wpbeginner.com/wp-tutorials/how-to-create-custom-rss-feeds-in-wordpress/

由于您必须自己收集和过滤多个博客中的帖子，因此多站点提要很复杂。为了简化一些命名，假设我想收集所有标记的帖子foo.

我写了几个类来管理这个：

FooTagFeed的代码太长，不雅观，无法包含在这里，但我将删除代码，以指导任何面临类似问题的人。

将此添加到我的主题的底部functions.php 文件：

# content/themes/main-theme/functions.php

/***************************************************
* Multi-Site Feed
* Based on http://www.wpbeginner.com/wp-tutorials/how-to-create-custom-rss-feeds-in-wordpress/
***************************************************/
add_action(\'init\', \'add_multisite_foo_feed\');
function add_multisite_foo_feed() {
  // Args: path (/feed/foo), callback (function below)
  add_feed(\'foo\', \'build_foo_tag_feed\');
}
function build_foo_tag_feed() {
  header(\'Content-Type: \' . feed_content_type(\'rss2\') . \'; charset=\' . get_option(\'blog_charset\'), true);
  get_template_part(\'foo_tag_feed\');
}

然后是我的feed类：

# content/themes/main-theme/foo_tag_feed.php

Class FooFeedPost {
    function __construct($wp_post) {}

    function as_rss_item() {}
}


class FooTagFeed {
    function __construct($wpdb) {
        $this->db = $wpdb;
    }

    function as_rss2() {
        $feed_posts = $this->fetch_posts_tagged_foo();

        // Sort by post date in DESC order.
        // Source: https://stackoverflow.com/a/10159521/6763239
        // Sorts in place and returns boolean.
        usort($feed_posts, function($a, $b) {
            return $a->timestamp < $b->timestamp;
        });
        $feed_posts = array_slice($feed_posts, 0, $this->item_limit);

        return $this->format_as_rss2($feed_posts);
    }

    function fetch_posts_tagged_foo() {
      $feed_posts = array();
      $blog_ids = $this->fetch_blog_ids();

      foreach ( $blog_ids as $blog_id ) {
          switch_to_blog($blog_id);
          $site_posts = $this->fetch_posts_tagged_foo_by_blog($blog_id);

          foreach ( $site_posts as $wp_post ) {
            $feed_posts[] = new FooFeedPost($wp_post);
          }

          restore_current_blog();
      }

      return $feed_posts;
    }

    function format_as_rss2($feed_posts) {}

    function fetch_blog_ids() {}

    function fetch_posts_tagged_foo_by_blog($blog_id) {}
}


$foo_feed = new FooFeedPost($wpdb);
echo $foo_feed->as_rss2();

饲料将在以下地点供应：https://my-multisite-blog.com/feed/foo

如果您想看到更多的代码，请点击我，我将尝试包含指向要点或其他内容的链接。