Yii2 で .htaccess を使用してフロントエンドとバックエンドのパスを非表示にする方法は?

Options +FollowSymlinks
RewriteEngine On

# Admin
RewriteCond %{REQUEST_URI} ^/(admin)
RewriteRule ^admin/assets/(.*)$ backend/web/assets/ [L]
RewriteRule ^admin/css/(.*)$ backend/web/css/ [L]

RewriteCond %{REQUEST_URI} !^/backend/web/(assets|css)/
RewriteCond %{REQUEST_URI} ^/(admin)
RewriteRule ^.*$ backend/web/index.php [L]

# Frontend
RewriteCond %{REQUEST_URI} ^/(assets|css)
RewriteRule ^assets/(.*)$ frontend/web/assets/ [L]
RewriteRule ^css/(.*)$ frontend/web/css/ [L]
RewriteRule ^js/(.*)$ frontend/web/js/ [L]
RewriteRule ^images/(.*)$ frontend/web/images/ [L]

RewriteCond %{REQUEST_URI} !^/(frontend|backend)/web/(assets|css)/
RewriteCond %{REQUEST_URI} !index.php
RewriteCond %{REQUEST_FILENAME} !-f [OR]
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule ^.*$ frontend/web/index.php

<code class="php">namespace common\components;

class Request extends \yii\web\Request {
    public $web;
    public $adminUrl;

    public function getBaseUrl(){
        return str_replace($this->web, "", parent::getBaseUrl()) . $this->adminUrl;
    }

    public function resolvePathInfo(){
        if($this->getUrl() === $this->adminUrl){
            return "";
        }else{
            return parent::resolvePathInfo();
        }
    }
}</code>

<code class="php">'request' => [
    'class' => 'common\components\Request',
    'web' => '/frontend/web'
],

'urlManager' => [
    'enablePrettyUrl' => true,
    'showScriptName' => false,
],</code>

<code class="php">'request' => [
    'class' => 'common\components\Request',
    'web' => '/backend/web',
    'adminUrl' => '/admin'
],

'urlManager' => [
    'enablePrettyUrl' => true,
    'showScriptName' => false,
],</code>

RewriteEngine On
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule ^(.*)$ /index.php?/ [L]