Alternative zu RewriteEngine On

<?php
if (preg_match('#^http://www.#i',$_SERVER['REQUEST_URI'])
{
$url = preg_replace('#^http://www.#i','#^http://#i',$_SERVER['REQUEST_URI']);
header("Status: 301");
header('Location: '.$url);
}
?>

<?php
header('Location: http://www.'.$_SERVER['SERVER_NAME'].$_SERVER['PHP_SELF'],true,301);
?>

<?php
//Duplicate Content per PHP verhindern
//Von ohne www. nach www. umleiten
if (!strstr($_SERVER['HTTP_HOST'],'www'))
{
     header('Location: http://www.'.$_SERVER['HOST'].$_SERVER['REQUEST_URI'],true,301);
}
//Von www. nach ohne umleiten
if (strstr($_SERVER['HTTP_HOST'],'www'))
{
    $host = str_replace('www.','',$_SERVER['HTTP_HOST']);
    header('Location: http://$host.$_SERVER['REQUEST_URI'],true,301);
}
?>

<?php
if (!strstr($_SERVER['HTTP_HOST'],'www'))
{
echo '<link rel="canonical" href="http://www.'.$_SERVER['HOST'].$_SERVER['REQUEST_URI'].'" / >',
}
?>

<?php
if(substr($_SERVER['HTTP_HOST'], 0, 4)!=='www.'){
  // wenn der Host kein "www." vorne dran hat, dann:
  echo '<link rel="canonical" href="http://www.',$_SERVER['HTTP_HOST'],$_SERVER['REQUEST_URI'],'" />';
}
?>