WordPress Plugin: T5 Editor Shortlink

t5-editor-shortlink.php

<?php # -*- coding: utf-8 -*-
/**
 * Plugin Name: T5 Editor Shortlink
 * Plugin URI:  https://gist.github.com/toscho/e5a189d6715e57c7cdf2
 * Description: Show the shortlink in the editor. Requires at least PHP 5.3.
 * Version:     08.05.15
 * Required:    4.0
 * Author:      Thomas Scholz <[email protected]>
 * Author URI:  http://toscho.de
 * License:     MIT
 * License URI: http://www.opensource.org/licenses/mit-license.php
 */

if ( is_admin() ) {
	add_action( 'load-post.php', function () {

		add_action( 'post_submitbox_misc_actions', function () {

			$post = get_post();

			if ( ! $post )
				return;

			$url = wp_get_shortlink( $post->ID );

			if ( ! $url )
				return;

			$url = esc_url( $url );

			printf(
				'
<div class="misc-pub-section">
	<label>
		Shortlink:
		<input type="text" value="%1$s" onclick="this.select()" class="widefat code" readonly>
	</label>
</div>',
				$url
			);
		} );
	});
}