Change Wordpress Admin URL

Here's an article from wordpress's site.

http://wordpress.org/support/topic/how-to-change-the-admin-url-or-wp-admin-to-secure-login

1. Add constant to wp-config.php

   define('WP_ADMIN_DIR', 'secret-folder');  define( 'ADMIN_COOKIE_PATH', SITECOOKIEPATH . WP_ADMIN_DIR);  

2. Add below filter to functions.php

   add_filter('site_url',  'wpadmin_filter', 10, 3);  function wpadmin_filter( $url, $path, $orig_scheme ) {      $old  = array( "/(wp-admin)/");      $admin_dir = WP_ADMIN_DIR;      $new  = array($admin_dir);      return preg_replace( $old, $new, $url, 1);  }

3. Add below line to .htaccess file

   RewriteRule ^secret-folder/(.*) wp-admin/$1?%{QUERY_STRING} [L]

I played around with this and there is a much simpler way to do this all in this one simple function below without having to muck around with anything else (create unnecessary folders, redirects, pages, etc.).

// Simple Query String Login page protectionfunction example_simple_query_string_protection_for_login_page() {$QS = '?mySecretString=foobar';$theRequest = 'http://' . $_SERVER['SERVER_NAME'] . '/' . 'wp-login.php' . '?'. $_SERVER['QUERY_STRING'];// these are for testing// echo $theRequest . '<br>';// echo site_url('/wp-login.php').$QS.'<br>';       if ( site_url('/wp-login.php').$QS == $theRequest ) {        echo 'Query string matches';    } else {        header( 'Location: http://' . $_SERVER['SERVER_NAME'] . '/' );    }}add_action('login_head', 'example_simple_query_string_protection_for_login_page');

This is very helpful topic. I made some little correction in the function and this is my version:

add_filter('site_url',  'wpadmin_filter', 10, 3); function wpadmin_filter( $url, $path, $orig_scheme ) {    $request_url = $_SERVER['REQUEST_URI'];    $check_wp_admin = stristr($request_url, 'wp-admin');    if($check_wp_admin){        wp_redirect( home_url( '404' ), 302 );        exit();    }    $old  = array( "/(wp-admin)/");    $admin_dir = WP_ADMIN_DIR;    $new  = array($admin_dir);    return preg_replace( $old, $new, $url, 1); }

Mainly for redirecting of wp-admin.

And most important part:

add_rewrite_rule( '^' . 'backend/(.*)','wp-admin/$1?%{QUERY_STRING}' );

To updates .htaccess rule.