How to Create Shortener URL Wordpress Plugins

Go to your \wp-content\plugins path, create new folder with name shortener.

Create new PHP file in shortener folder with name shortener.php.

Write this code:

<?php 
/*
Plugin Name: URL Shortener
Plugin URI: http://inochisoftware.com
Description: Create shortener URL
Author: Novian Agung
Version: 1.0
Author URI: http://inochisoftware.com
*/

global $shortener_db_version;
global $shortener_table_name;

$shortener_db_version = '1.0';

/* Create new table in your Wordpress database */
if ( ! function_exists( 'shortener_install' ) ) :
function shortener_install() {
    global $wpdb;
    global $shortener_db_version;

    $table_name = $wpdb->prefix . 'direct_url';
    $shortener_table_name = $table_name;
    
    $charset_collate = $wpdb->get_charset_collate();

    $sql = "CREATE TABLE $table_name (
        intId MEDIUMINT(9) NOT NULL AUTO_INCREMENT,
        strName VARCHAR(20) NOT NULL,
        strUrl VARCHAR(250) DEFAULT '' NOT NULL,
        PRIMARY KEY (intId)
    ) $charset_collate;";
    
    require_once( ABSPATH . 'wp-admin/includes/upgrade.php' );
    
    dbDelta( $sql );
    
    /* Add new option/saving key on meta Wordpress */
    add_option( 'shortener_db_version', $shortener_db_version );
    add_option( 'shortener_table_name', $shortener_table_name );
    
    update_option( "shortener_db_version", $shortener_db_version );
}
endif;

/* Register function "shortener_install" to Wordpress platform */
register_activation_hook( __FILE__, 'shortener_install' );

/* Check for plugin update */
if ( ! function_exists( 'shortener_update_db_check' ) ) :
function shortener_update_db_check() {
    global $shortener_db_version;
    if ( get_site_option( 'shortener_db_version' ) != $shortener_db_version ) {
        shortener_install();
    }
}
endif;

/* Add new action to Wordpress platform when plugin loaded */
add_action( 'plugins_loaded', 'shortener_update_db_check' );

/* CORE FUNCTION */

/* Create randoming key for URL id */
if ( ! function_exists( 'shortener_generate_key' ) ) :
    function shortener_generate_key($length = 12) {
        $pool = array_merge(range(0,9), range('a', 'z'), range('A', 'Z'));
        $key = "";
        for ($i=0; $i < $length; $i++) {
            $key .= $pool[mt_rand(0, count($pool) - 1)];
        }
        return $key;
    }
endif;

/* Saving key to database (new table) */
if ( ! function_exists( 'shortener_generate_url' ) ) :
function shortener_generate_url($url) {
    global $wpdb;
    $table_name = get_site_option( 'shortener_table_name' );
    
    $name = '';
    
    /* Checking for key has already exist */
    $sql = $wpdb->prepare("SELECT `strName` FROM $table_name WHERE `strUrl` = %s", $url);
    $last_name = $wpdb->get_var($sql);
    
    if (empty($last_name)){
        /* Generate a key */
        $name = shortener_generate_key();
        
        /* Insert when key not exist */
        $sql = $wpdb->prepare("INSERT INTO $table_name (`strName`,`strUrl`) values (%s, %s)", $name, $url);
        $wpdb->query($sql);
    } else {
       $name = $last_name;
    }
    
    return $name;
}
endif;

/* Create a new Wordpress short code */
if ( ! function_exists( 'shortener_url_func' ) ) :
function shortener_url_func( $atts, $text = "" ){
    $atts = shortcode_atts( 
        array(
            'url' => ''
        ), 
        $atts, 'short' );
    
    $url = $atts['url'];
    
    /* Get your blog/web URL */
    $main_url = get_site_url();
    
    /* Generate key for URL input */
    $key = shortener_generate_url($url);
    
    /* Generate new URL */
    $shortener_url = $main_url . '/goto/' . $key;
    
    return ' . $shortener_url . '" title="' . $text . '" target="_blank">' . $text . '';
}
endif;

/* Add a new short code to Wordpress */
add_shortcode( 'short', 'shortener_url_func' ); 

/* Create a redirect URL function */
if ( ! function_exists( 'shortener_redirect_url' ) ) :
function shortener_redirect_url(){
    global $wpdb;
    global $wp_query;
    
    /* When error 404 found */
    if(is_404()){
        /* Get Wordpress query */
        $query = $wp_query->query;
        
        if ($query){
            /* Get attachment field */
            $attachment = $query["attachment"];
            
            /* If attachment not found then name field */
            if (!$attachment){
                $attachment = $query["name"];
            }
            
            /* If name not found then pagename field */
            if (!$attachment){
                $pagename = $query["pagename"];
                
                /* If pagename found */
                if ($pagename){
                    /* Explode pagename value then get attachment key */
                    $arr_pagename = explode("goto/", $pagename);
                    
                    if (count($arr_pagename) == 2){
                        $attachment = $arr_pagename[1];
                    }
                }
            }
            
            /* If attachment found then name field */
            if ($attachment){
                /* Make sure length $attachment is 12 */
                if (strlen($attachment) == 12){
                    $table_name = get_site_option( 'shortener_table_name' );
                    
                    /* Get attachment key from database */
                    $sql = $wpdb->prepare("SELECT `strUrl` FROM $table_name WHERE `strName` = %s", $attachment);
                    $url_redirect = $wpdb->get_var($sql);
                    
                    if ($url_redirect){
                        /* Redirect page */
                        if ( wp_redirect( $url_redirect ) ) {
                            exit;
                        }
                    }
                }
            }
        }
    }
}
endif;

/* Add a new action to Wordpress */
add_action('template_redirect', 'shortener_redirect_url' );
?>

Save your code. Open your Wordpress dashboard, go to Plugins page option. Activate your plugin.

Create a new Post. For example, write this:

Visit my [short url="http://www.facebook.com/"]Facebook[/short] to ... ...

Save and publish your post then visit your post.

See, your link in post (http://www.facebook.com) will convert to shorten URL. Try to clik the link.