PHP Secure URL String base64 Encoding and Decoding

If you use the base64_encode and base64_decode methods directly, the resulting string may not be applicable to the URL address. The following methods can solve this problem:

URL Secure String Encoding:

function urlsafe_b64encode($string) {

   $data = base64_encode($string);

   $data = str_replace(array('+','/','='),array('-','_',''),$data);

   return $data;

 }

URL Secure String Decoding:

function urlsafe_b64decode($string) {

   $data = str_replace(array('-','_'),array('+','/'),$string);

   $mod4 = strlen($data) % 4;

   if ($mod4) {

       $data .= substr('====', $mod4);

   }

   return base64_decode($data);

 }