protected function Markdown::encodeEntityObfuscatedAttribute in Markdown 7

* Input: some text to obfuscate, e.g. "mailto:foo@example.com" * * Output: the same text but with most characters encoded as either a * decimal or hex entity, in the hopes of foiling most address * harvesting spam bots. E.g.: * * mailto:foo * @example.co * m * * Note: the additional output $tail is assigned the same value as the * ouput, minus the number of characters specified by $head_length. * * Based by a filter by Matthew Wickline, posted to BBEdit-Talk. * With some optimizations by Milian Wolff. Forced encoding of HTML * attribute special characters by Allan Odgaard. * *

Parameters

string $text: * @param string &$tail * @param integer $head_length * @return string

1 call to Markdown::encodeEntityObfuscatedAttribute()

Markdown::encodeURLAttribute in includes/Markdown.php

* Encode text for a double-quoted HTML attribute containing a URL, * applying the URL filter if set. Also generates the textual * representation for the URL (removing mailto: or tel:) storing it in $text. * This function is *not* suitable for…

File

includes/Markdown.php, line 1687

Class

Markdown

Markdown Parser Class

Namespace

Michelf

Code

protected function encodeEntityObfuscatedAttribute($text, &$tail = null, $head_length = 0) {
  if ($text == "") {
    return $tail = "";
  }
  $chars = preg_split('/(?<!^)(?!$)/', $text);
  $seed = (int) abs(crc32($text) / strlen($text));

  // Deterministic seed.
  foreach ($chars as $key => $char) {
    $ord = ord($char);

    // Ignore non-ascii chars.
    if ($ord < 128) {
      $r = $seed * (1 + $key) % 100;

      // Pseudo-random function.
      // roughly 10% raw, 45% hex, 45% dec
      // '@' *must* be encoded. I insist.
      // '"' and '>' have to be encoded inside the attribute
      if ($r > 90 && strpos('@"&>', $char) === false) {

        /* do nothing */
      }
      else {
        if ($r < 45) {
          $chars[$key] = '&#x' . dechex($ord) . ';';
        }
        else {
          $chars[$key] = '&#' . $ord . ';';
        }
      }
    }
  }
  $text = implode('', $chars);
  $tail = $head_length ? implode('', array_slice($chars, $head_length)) : $text;
  return $text;
}