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Peter J. Herrel edited this page Jan 30, 2015 · 7 revisions
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What does the plugin do?

WP What Links Here implements "what links here" functionality in WordPress, like seen on e.g. Wikipedia.

How does it work?

Whenever a page or post is published or edited, it is added to a background queue. At regular intervals this queue is processed by a cron job, updating the relations between posts linking and linked to.

How do I display the list?

(a) Use the [wp_what_links_here] shortcode to display the list in your post content.

(b) Echo the list in a template file:

$wlh = do_shortcode( '[wp_what_links_here]' );
if( '' !== $wlh )
{
    echo '<h2>What links here</h2>';
    echo $wlh;
}

(c) Append the list to the post content using a filter, e.g.:

add_filter( 'the_content', 'my_wp_wlh_the_content', 10, 1 );
function my_wp_wlh_the_content( $content )
{
    $wlh = do_shortcode( '[wp_what_links_here]' );

    if( '' !== $wlh )
        return $content . $wlh;

    return $content;
}

(d) To get a list of IDs, use wp_what_links_here( get_the_ID() ).

Are custom post types supported?

Yes. By default, the plugin works with all public post types. WordPress' built-in public post types are: post, page, and attachment.

To whitelist a specific set of post types (e.g. only interlink pages and posts, but exclude the product post type), use the wp_wlh_post_types filter:

<?php
add_filter( 'wp_wlh_post_types', 'config_wp_wlh_post_types', 0, 1 );
function config_wp_wlh_post_types( $post_types )
{
    return array( 'post', 'some_post_type', 'another_post_type' );
}

How do I change the cron interval?

You can change the default interval of two hours by defining the WP_WLH_CRON_INTERVAL constant in the wp-config.php file of your WordPress installation. Use an integer value representing seconds, e.g.:

define( 'WP_WLH_CRON_INTERVAL', 1800 ); // every 30 minutes

To ensure the background queue does not grow too large, choose a value in correlation to the degree of editing activity on your site.

Tip: You can use the WP Crontrol plugin to run the cron job at any time.

Any hooks I can use?

action hooks

  • wp_wlh_loaded
  • wp_wlh_queue_add
  • wp_wlh_queue_remove
  • wp_wlh_do_cron

filter hooks

  • wp_wlh_post_types
  • wp_wlh_cron_schedules
  • wp_wlh_queue_add
  • wp_wlh_queue_remove
  • wp_wlh_check_link
  • wp_wlh_shortcode_query_args
  • wp_wlh_shortcode_output_open
  • wp_wlh_shortcode_output_item
  • wp_wlh_shortcode_output_close
  • wp_wlh_shortcode_output
  • wp_wlh_linking_here
  • wp_wlh_linking_to
  • wp_wlh_the_content
  • wp_wlh_get_links

Code Snippets

Order posts by name

To sort the posts by title, put the following in a custom plugin or in the functions.php file of your (child) theme:

add_filter( 'wp_wlh_shortcode_query_args', 'my_wp_wlh_shortcode_query_args', 10, 1 );
function my_wp_wlh_shortcode_query_args( $query_args )
{
    $query_args['order'] = 'ASC';
    $query_args['orderby'] = 'title';

    return $query_args;
}