title: If rewrite map doesn't exist got to 404
body: <p>I've created a rewrite map that's working well:</p>
  
  <p>.htaccess</p>
  
  <p><code>RewriteRule ^([^/\.]+)/?$ index.php?page=${mymap:$1} [L]</code></p>
  
  <p>mymap.txt</p>
  
  <pre><code>home 1
  about 2
  contact 3
  </code></pre>
  
  <p>So www.myurl/home works fine, but www.myurl/nonexistant_page doesn't exist in mymap.txt so I get an SQL error. Is there a way to check if the map exist and if not got to 404 page?</p>