filter/emailprotect/classes/text_filter.php

   1 <?php
   2 // This file is part of Moodle - http://moodle.org/
   3 //
   4 // Moodle is free software: you can redistribute it and/or modify
   5 // it under the terms of the GNU General Public License as published by
   6 // the Free Software Foundation, either version 3 of the License, or
   7 // (at your option) any later version.
   8 //
   9 // Moodle is distributed in the hope that it will be useful,
  10 // but WITHOUT ANY WARRANTY; without even the implied warranty of
  11 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12 // GNU General Public License for more details.
  13 //
  14 // You should have received a copy of the GNU General Public License
  15 // along with Moodle.  If not, see <http://www.gnu.org/licenses/>.
  16
  17 namespace filter_emailprotect;
  18
  19 /**
  20  * Basic email protection filter.
  21  *
  22  * This class looks for email addresses in Moodle text and hides them using the Moodle obfuscate_text function.
  23  *
  24  * @package    filter_emailprotect
  25  * @subpackage emailprotect
  26  * @copyright  2004 Mike Churchward
  27  * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
  28  */
  29 class text_filter extends \core_filters\text_filter {
  30     #[\Override]
  31     public function filter($text, array $options = []) {
  32         // Do a quick check using stripos to avoid unnecessary work.
  33         if (strpos($text, '@') === false) {
  34             return $text;
  35         }
  36
  37         // Regular expression to define a standard email string.
  38         $emailregex = '((?:[\w\.\-])+\@(?:(?:[a-zA-Z\d\-])+\.)+(?:[a-zA-Z\d]{2,4}))';
  39
  40         // Pattern to find a mailto link with the linked text.
  41         $pattern = '|(<a\s+href\s*=\s*[\'"]?mailto:)' . $emailregex . '([\'"]?\s*>)' . '(.*)' . '(</a>)|iU';
  42         $text = preg_replace_callback($pattern, [self::class, 'alter_mailto'], $text);
  43
  44         // Pattern to find any other email address in the text.
  45         $pattern = '/(^|\s+|>)' . $emailregex . '($|\s+|\.\s+|\.$|<)/i';
  46         $text = preg_replace_callback($pattern, [self::class, 'alter_email'], $text);
  47
  48         return $text;
  49     }
  50
  51     /**
  52      * Obfuscate the email address.
  53      *
  54      * @param mixed $matches
  55      * @return string
  56      */
  57     private function alter_email($matches) {
  58         return $matches[1] . obfuscate_text($matches[2]) . $matches[3];
  59     }
  60
  61     /**
  62      * Obfuscate the mailto link.
  63      *
  64      * @param mixed $matches
  65      * @return string
  66      */
  67     private function alter_mailto($matches) {
  68         return obfuscate_mailto($matches[2], $matches[4]);
  69     }
  70 }