HTML Email Address Obfuscation (PHP)

Category: PHP

Small class, intended to be used as a callback for preg_replace_callback to obfuscate email addresses. You can also simply pass a string in rather than being obliged to use preg_replace_callback

Supports a number of obfuscation modes

  • part - e.g. test@
  • full - e.g.
  • none - e.g. test@example.com
  • htmlencode - Generates a javascript snippet to write the address in
document.write('test');
document.write('@');
document.write('example.com');

Although it's targetted with HTML output in mind, it can just as easily be used on plain text

Details

Snippet

class EmailObfusCallback {

    /** Constructor
    *
    * @arg obfustype - one of "part","full","none","htmlencode"
    * @return void
    */
    function __construct($obfustype="full"){
        $this->obfustype = $obfustype;
    }

    /** Function to obscure email addresses in a HTML page
    * Intended to be callaed from preg_replace_callback
    *
    * @arg str - the regex match 
    * @return str
    */
    function obscureEmail($match){
            global $conf;
            $parts = explode('@',$match[0]);
            switch (strtolower($this->obfustype)){
                    case 'part':
                            $str = "{$parts[0]}@<Domain Hidden>";
                            break;
                    case 'full':
                            $str = "<Email Hidden>";
                            break;
                    case 'none':
                            $str = $match[0];
                            break;
                    default:
                            $u = '';
                            for ($i = 0; $i < strlen($parts[0]); $i++){
                                    $u .= '&#' . ord($parts[0][$i]) . ';';
                            }
                            $d = '';
                            for ($i = 0; $i < strlen($parts[1]); $i++){
                                    $d .= '&#' . ord($parts[1][$i]) . ';';
                            }
                            $str = "<script type='text/javascript'>\n".
                                    "document.write('$u');\n" .
                                    "document.write('@');\n\n" .
                                    "document.write('$d');" .
                                    "</script>";
            }
            return $str;
    }

}

Usage Example

$str = "Email me at test@example.com for more info";
$callback = new EmailObfusCallback('part');
$regex = "/(([A-Z0-9._%-\+]+)@([A-Z0-9_%-]+)\.([A-Z\.]{2,20}))/i";
echo preg_replace_callback($regex,array($callback, 'obscureEmail'),$str) . "\n";

$callback = new EmailObfusCallback('full');
echo preg_replace_callback($regex,array($callback, 'obscureEmail'),$str) . "\n";

$callback = new EmailObfusCallback('none');
echo preg_replace_callback($regex,array($callback, 'obscureEmail'),$str) . "\n";

$callback = new EmailObfusCallback('htmlencode');
echo preg_replace_callback($regex,array($callback, 'obscureEmail'),$str) . "\n";