Example of using a URL shortener since leenk.me v2.10.0

leenkme-shortener.php

<?php
/*
 * Add this file to the wp-content/mu-plugins/ directory
 */
	
function my_leenkme_shortener( $permalink, $post_id) {
	if ( $existing = get_post_meta( $post_id, '_leenkme_short_url', true ) ) {
		
		$permalink = $existing;
	
	} else {
		
		$bitly_api = "http://api.bitly.com/v3/shorten"; 
		$bitly_args = array(  
			'login' => 'YOUR_BITLY_USERNAME',  //CHANGEME
			'apiKey' => 'YOUR_BITLY_API_KEY',  //CHANGEME
			'longURL' => $permalink,  
			'format' => 'txt',  
			'domain' => 'bit.ly' // either bit.ly or j.mp  
		);  

    $bitly_query = $bitly_api . '?' .  http_build_query( $bitly_args );
	    
		$result = wp_remote_request( $bitly_query );
		
		if ( is_wp_error( $result ) ) { //if we get an error just us the normal permalink URL
		
			return $permalink;
		
		} else if ( !empty( $result ) && !empty( $result['body'] ) ) {
			
			update_post_meta( $post_id, '_leenkme_short_url', trim( $result['body'] ) );
			return trim( $result['body'] ); 
			
		}
		
	}
	return $permalink;
}
add_filter( 'leenkme_get_permalink', 'my_leenkme_shortener', 10, 2 );