pubsubhubbub/wordpress-pubsubhubbub

<?php
/**
 * The WebSub/PubSubHubbub publisher class
 */
class PubSubHubbub_Publisher {
    /**
     * Function that is called whenever a new post is published
     *
     * @param int $post_id the post-id
     * @return int the post-id
     */
    public static function publish_post( $post_id ) {
        // we want to notify the hub for every feed
        $feed_urls = self::get_feed_urls_by_post_id( $post_id );

        // publish them
        self::publish_to_hub( $feed_urls );
    }

    /**
     * Function that is called whenever a new comment is published
     *
     * @param int $comment_id the comment-id
     * @return int the comment-id
     */
    public static function publish_comment( $comment_id ) {
        // get default comment-feeds
        $feed_urls   = array();
        $feed_urls[] = get_bloginfo( 'comments_atom_url' );
        $feed_urls[] = get_bloginfo( 'comments_rss2_url' );

        $feed_urls = apply_filters( 'pubsubhubbub_comment_feed_urls', $feed_urls, $comment_id );

        // publish them
        self::publish_to_hub( $feed_urls );
    }

    /**
     * Accepts either a single url or an array of urls
     *
     * @param string|array $topic_urls a single topic url or an array of topic urls
     */
    public static function publish_update( $topic_urls, $hub_url ) {
        if ( ! isset( $hub_url ) ) {
            return new WP_Error( 'missing_hub_url', __( 'Please specify a hub url', 'pubsubhubbub' ) );
        }

        if ( ! preg_match( '|^https?://|i', $hub_url ) ) {
            /* translators: %s is the $hub_url */
            return new WP_Error( 'invalid_hub_url', sprintf( __( 'The specified hub url does not appear to be valid: %s', 'pubsubhubbub' ), esc_url( $hub_url ) ) );
        }

        if ( ! isset( $topic_urls ) ) {
            return new WP_Error( 'missing_topic_url', __( 'Please specify a topic url', 'pubsubhubbub' ) );
        }

        // check that we're working with an array
        if ( ! is_array( $topic_urls ) ) {
            $topic_urls = array( $topic_urls );
        }

        // set the mode to publish
        $post_string = 'hub.mode=publish';
        // loop through each topic url
        foreach ( $topic_urls as $topic_url ) {
            // lightweight check that we're actually working w/ a valid url
            if ( preg_match( '|^https?://|i', $topic_url ) ) {
                // append the topic url parameters
                $post_string .= '&hub.url=' . esc_url( $topic_url );
            }
        }

        $wp_version = get_bloginfo( 'version' );
        $user_agent = apply_filters( 'http_headers_useragent', 'WordPress/' . $wp_version . '; ' . get_bloginfo( 'url' ) );

        $args = array(
            'timeout' => 100,
            'limit_response_size' => 1048576,
            'redirection' => 20,
            'user-agent' => "$user_agent; PubSubHubbub/WebSub",
            'headers' => array(
                'content-type' => 'application/x-www-form-urlencoded'
            ),
            'body' => $post_string,
        );

        // make the http post request
        return wp_remote_post( $hub_url, $args );
    }

    /**
     * The ability for other plugins to hook into the PuSH code
     *
     * @param array $feed_urls a list of feed urls you want to publish
     */
    public static function publish_to_hub( $feed_urls ) {
        // remove dups (ie. they all point to feedburner)
        $feed_urls = array_unique( $feed_urls );

        // get the list of hubs
        $hub_urls = self::get_hubs();

        // loop through each hub
        foreach ( $hub_urls as $hub_url ) {
            // publish the update to each hub
            $response = self::publish_update( $feed_urls, $hub_url );

            do_action( 'pubsubhubbub_publish_update_response', $response );
        }
    }

    /**
     * Get the endpoints from the WordPress options table
     * valid parameters are "publish" or "subscribe"
     *
     * @uses apply_filters() Calls 'pubsubhubbub_hub_urls' filter
     */
    public static function get_hubs() {
        $endpoints = get_option( 'pubsubhubbub_endpoints' );

        // Fail with an empty array when option retrieval fails
        if ( ! $endpoints ) {
            $hub_urls = Pubsubhubbub::DEFAULT_HUBS;
        } else {
            $hub_urls = explode( PHP_EOL, $endpoints );
        }

        return apply_filters( 'pubsubhubbub_hub_urls', $hub_urls );
    }

    /**
     * Returns a list of feed URLs for a given Post
     *
     * @param int $post_id The post ID
     *
     * @return array An array of feed URLs
     */
    public static function get_feed_urls_by_post_id( $post_id ) {
        $post = get_post( $post_id );

        $feed_types = pubsubhubbub_get_supported_feed_types();

        foreach ( $feed_types as $feed_type ) {
            $feed_urls[] = get_feed_link( $feed_type );

            // add tag-feeds
            $tags = wp_get_post_tags( $post_id );

            foreach ( $tags as $tag ) {
                $feed_urls[] = get_term_feed_link( $tag->term_id, 'post_tag', $feed_type );
            }

            // add category-feeds
            $categories = wp_get_post_categories( $post_id );

            foreach ( $categories as $category ) {
                $feed_urls[] = get_term_feed_link( $category, 'category', $feed_type );
            }

            // add author-feeds
            $feed_urls[] = get_author_feed_link( $post->post_author, $feed_type );
        }

        if ( current_theme_supports( 'microformats2' ) ) {
            $feed_urls[] = site_url( '/' );
        }

        $feed_urls = apply_filters( 'pubsubhubbub_feed_urls', $feed_urls, $post_id );

        return $feed_urls;
    }
}