Show WordPress Media Attachments in Insert/Edit Link dialog

show-media-attachments-in-link-dialog.php

<?php

/**
 * Main plugin file.
 *
 * @package    Show Media Attachments in Link Dialog
 * @license    GPL2
 * Author: Adam Taylor <hello@adamtaylor.dev>
 */

/**
 * Plugin Name:     Show Media Attachments in Link Dialog
 * Description:     Adds media attachments with specific extensions to the search window in the Insert/Edit Link dialog. If chosen, a download link to the attachment will be inserted. Filters are available to decide which media attachments are shown.
 * Plugin URI:      https://gist.github.com/IAmAdamTaylor/81b92080dce7ba95fe2a10f96f69f124
 * Version:         1.0.0
 * Author:          Adam Taylor <hello@adamtaylor.dev>
 * Author URI:      https://adamtaylor.dev
 * License:         GPL2
 */

/*  Copyright 2020 Adam Taylor  (email : hello@adamtaylor.dev)

    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License, version 2, as 
    published by the Free Software Foundation.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with this program; if not, write to the Free Software
    Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
*/

add_filter('wp_link_query_args', 'smalg_modify_link_query_args');
function smalg_modify_link_query_args( $query ) {
    // include 'inherit' post statuses so attachments are returned
    $query['post_status'] = (array) $query['post_status'];
    $query['post_status'][] = 'inherit';
    
    // use post query filters
    $query['suppress_filters'] = false;

    // use custom query arg detectable in other filters
    $query['smalg__media_last'] = apply_filters('smalg_show_media_last', true);

    $allowed_exts = apply_filters('smalg_allowed_extensions', array('pdf'));
    $meta_query = array(
        'relation' => 'OR',
        'meta_not_exists' => array(
            'key' => '_wp_attached_file',
            'compare' => 'NOT EXISTS',
        ),
        'ext_like' => array(),
    );

    foreach ($allowed_exts as $key => $ext) {
        $meta_query['ext_like'][] = array(
            'key' => '_wp_attached_file',
            'value' => '.'.$ext,
            'compare' => 'LIKE',
        );
    }

    if ( isset($query['meta_query']) && $query->meta_query ) {
        // merge meta queries
        $query['meta_query'] = array(
            'relation' => 'AND',
            $query['meta_query'],
            $meta_query
        );
    } else {
        $query['meta_query'] = $meta_query;
    }
    
    return $query;
}

// link to media file's permalink instead of attachment page
add_filter( 'wp_link_query', 'smalg_modify_link_query_results', 10, 2 );
function smalg_modify_link_query_results( $results, $query ) {
    return array_map(function($r) {
        if ( 'Media' === $r['info'] ) {
            $permalink = wp_get_attachment_url( $r['ID'] );
            $path = parse_url( $permalink, PHP_URL_PATH );
            $ext = pathinfo( $path, PATHINFO_EXTENSION );

            $r['title'] = $r['title'].'.'.$ext;
            $r['permalink'] = wp_get_attachment_url($r['ID']);
        }

        return $r;
    }, $results);
}

// high priority to ensure it runs after some plugins like Post Types Order
add_filter('posts_orderby', 'smalg_order_search_by_posttype', 900, 2);
function smalg_order_search_by_posttype( $orderby, $wp_query ){
    if( 
        $wp_query->is_admin && 
        isset($wp_query->query['smalg__media_last']) &&
        $wp_query->query['smalg__media_last']
    ) {
        global $wpdb;
        // order as: not attachments by post date DESC -> attachments
        $orderby = "
            CASE WHEN {$wpdb->prefix}posts.post_type = 'attachment' THEN '__'
            ELSE {$wpdb->prefix}posts.post_date END DESC";
    }

    return $orderby;
}

One of the things that's always annoyed me about WordPress's Insert Link dialog window is that you can't search for PDFs and other attachments in your media library. The workaround to upload the file to the Media Library, open it and copy-paste the URL has always felt clunky to me.

This plugin makes that issue go away by adding media attachments with specific extensions into that search window! It also works with ACF Link fields as they use the same Insert Link dialog.

By default only PDFs are shown, however you can filter this to include others such as .docx if needed.

To install

1. Create a new file in /wp-content/mu-plugins/ and add the code from the Gist.
2. Save the file.
3. Done! Since the file was placed in mu-plugins WordPress will start using it straight away, no need to activate.

Filters

There are 2 filters available to use in this plugin:

smalg_allowed_extensions

Filter the list of file extensions that decide which media attachments are shown in the search dialog.
Defaults to: array('pdf')

When filtering, make sure to return an array and do not include the period before the extension, i.e. 'docx' instead of '.docx'.

/**
 * @param  array $extensions A list of file extensions to show in the search dialog.
 * @return array
 */
add_filter('smalg_allowed_extensions', 'gistiaat_smalg_allowed_extensions');
function gistiaat_smalg_allowed_extensions( $extensions ) {
    $extensions = array('pdf', 'docx');
    return $extensions;
} 

smalg_show_media_last

To keep the search dialog window clean, media attachments are shown last by default. You can use this filter to turn off that behaviour and show the search dialog list in newest to oldest posts order (the WordPress default).
Defaults to: true

// Use WordPress's quick return false function to disable it globally with one line...
add_filter('smalg_show_media_last', '__return_false');

// ... or use a separate function if you need fine grained control.

/**
 * @param  boolean $show_media_last True to show media attachments at the end of the search dialog list.
 * @return boolean
 */
add_filter('smalg_show_media_last', 'gistiaat_smalg_show_media_last');
function gistiaat_smalg_show_media_last( $show_media_last ) {
    // ... some condition
    return $show_media_last;
}