1 common.inc valid_url($url, $absolute = FALSE)

Verifies the syntax of the given URL.

This function should only be used on actual URLs. It should not be used for Backdrop menu paths, which can contain arbitrary characters. Valid values per RFC 3986.


$url: The URL to verify.

$absolute: Whether the URL is absolute (beginning with a scheme such as "http:").

Return value

TRUE if the URL is in a valid format.:

Related topics


core/includes/common.inc, line 1427
Common functions that many Backdrop modules will need to reference.


function valid_url($url, $absolute = FALSE) {
  if ($absolute) {
    return (bool) preg_match("
      /^                                                      # Start at the beginning of the text
      (?:ftp|https?|feed):\/\/                                # Look for ftp, http, https or feed schemes
      (?:                                                     # Userinfo (optional) which is typically
        (?:(?:[\w\.\-\+!$&'\(\)*\+,;=]|%[0-9a-f]{2})+:)*      # a username or a username and password
        (?:[\w\.\-\+%!$&'\(\)*\+,;=]|%[0-9a-f]{2})+@          # combination
        (?:[a-z0-9\-\.]|%[0-9a-f]{2})+                        # A domain name or a IPv4 address
        |(?:\[(?:[0-9a-f]{0,4}:)*(?:[0-9a-f]{0,4})\])         # or a well formed IPv6 address
      (?::[0-9]+)?                                            # Server port number (optional)
        (?:[\w#!:\.\?\+=&@$'~*,;\/\(\)\[\]\-]|%[0-9a-f]{2})   # The path and query (optional)
    $/xi", $url);
  else {
    return (bool) preg_match("/^(?:[\w#!:\.\?\+=&@$'~*,;\/\(\)\[\]\-]|%[0-9a-f]{2})+$/i", $url);