htaccess Apache to Litespeed

Question

I'm using the following rewrite on my dev environment (Apache 2) and it works fine, I uploaded to my live environment (LiteSpeed) and it no longer works :(

Any ideas why given the following?

I'm using the "P" directive "mod_proxy" which my host doesn't support. How can I get around this?

<IfModule mod_rewrite.c>
  Options +FollowSymLinks
  RewriteEngine On

  RewriteBase /

  RewriteCond $1 !\.(gif|jpe?g|png)$ [NC]
  RewriteCond %{REQUEST_FILENAME} !-f
  RewriteCond %{REQUEST_FILENAME} !-d
  RewriteCond %{HTTP_HOST} !^www\. [NC]
  RewriteCond %{HTTP_HOST} ^([^.]+)\.example\.com
  RewriteRule ^(.*)$ http://example.com/folder/%1/$1 [QSA,NC,P]

  # Removes index.php
  RewriteCond $1 !\.(gif|jpe?g|png)$ [NC]
  RewriteCond %{REQUEST_FILENAME} !-f
  RewriteCond %{REQUEST_FILENAME} !-d
  RewriteRule ^(.*)$ index.php?/$1 [L]

</IfModule>

Answer 1

I took a different approach to this problem. Apparently the mod_proxy method is inefficient so I solved it in PHP using some simple code to determine the subdomain and apply a conditional to check that $subdomain is not an empty string.

$url_parts = explode('.', str_replace('.example.com', '', $_SERVER['HTTP_HOST']));
$subdomain = ($url_parts[0] !== '') ? $url_parts[0] : '';

I'm just redirecting to the correct page once I know that there is a subdomain.