Should PHP header locations be encoded?

Question

Should PHP header locations be encoded?

header("Location: ".$_SERVER["REQUEST_URI"]);
header("Location: ".rawurlencode($_SERVER["REQUEST_URI"]));

If so, why, when, and how?

Answer 1

You only need to encode it, if you have some special chars (defined in RFC1806) in your URL. Especially you should encode all URLs with the following characters: {}|\^~[]` (as of RFC1738)