/filter/urltolink/filter.php
PHP | 177 lines | 72 code | 24 blank | 81 comment | 12 complexity | fc60cec1604f1e56fd49da0963419329 MD5 | raw file
- <?php
- // This file is part of Moodle - http://moodle.org/
- //
- // Moodle is free software: you can redistribute it and/or modify
- // it under the terms of the GNU General Public License as published by
- // the Free Software Foundation, either version 3 of the License, or
- // (at your option) any later version.
- //
- // Moodle is distributed in the hope that it will be useful,
- // but WITHOUT ANY WARRANTY; without even the implied warranty of
- // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- // GNU General Public License for more details.
- //
- // You should have received a copy of the GNU General Public License
- // along with Moodle. If not, see <http://www.gnu.org/licenses/>.
- /**
- * Filter converting URLs in the text to HTML links
- *
- * @package filter
- * @subpackage urltolink
- * @copyright 2010 David Mudrak <david@moodle.com>
- * @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
- */
- defined('MOODLE_INTERNAL') || die();
- class filter_urltolink extends moodle_text_filter {
- /**
- * @var array global configuration for this filter
- *
- * This might be eventually moved into parent class if we found it
- * useful for other filters, too.
- */
- protected static $globalconfig;
- /**
- * Apply the filter to the text
- *
- * @see filter_manager::apply_filter_chain()
- * @param string $text to be processed by the text
- * @param array $options filter options
- * @return string text after processing
- */
- public function filter($text, array $options = array()) {
- if (!isset($options['originalformat'])) {
- // if the format is not specified, we are probably called by {@see format_string()}
- // in that case, it would be dangerous to replace URL with the link because it could
- // be stripped. therefore, we do nothing
- return $text;
- }
- if (in_array($options['originalformat'], explode(',', get_config('filter_urltolink', 'formats')))) {
- $this->convert_urls_into_links($text);
- }
- return $text;
- }
- ////////////////////////////////////////////////////////////////////////////
- // internal implementation starts here
- ////////////////////////////////////////////////////////////////////////////
- /**
- * Given some text this function converts any URLs it finds into HTML links
- *
- * @param string $text Passed in by reference. The string to be searched for urls.
- */
- protected function convert_urls_into_links(&$text) {
- //I've added img tags to this list of tags to ignore.
- //See MDL-21168 for more info. A better way to ignore tags whether or not
- //they are escaped partially or completely would be desirable. For example:
- //<a href="blah">
- //<a href="blah">
- //<a href="blah">
- $filterignoretagsopen = array('<a\s[^>]+?>');
- $filterignoretagsclose = array('</a>');
- filter_save_ignore_tags($text,$filterignoretagsopen,$filterignoretagsclose,$ignoretags);
- // Check if we support unicode modifiers in regular expressions. Cache it.
- // TODO: this check should be a environment requirement in Moodle 2.0, as far as unicode
- // chars are going to arrive to URLs officially really soon (2010?)
- // Original RFC regex from: http://www.bytemycode.com/snippets/snippet/796/
- // Various ideas from: http://alanstorm.com/url_regex_explained
- // Unicode check, negative assertion and other bits from Moodle.
- static $unicoderegexp;
- if (!isset($unicoderegexp)) {
- $unicoderegexp = @preg_match('/\pL/u', 'a'); // This will fail silently, returning false,
- }
- // TODO MDL-21296 - use of unicode modifiers may cause a timeout
- $urlstart = '(?:http(s)?://|(?<!://)(www\.))';
- $domainsegment = '(?:[\pLl0-9][\pLl0-9-]*[\pLl0-9]|[\pLl0-9])';
- $numericip = '(?:(?:[0-9]{1,3}\.){3}[0-9]{1,3})';
- $port = '(?::\d*)';
- $pathchar = '(?:[\pL0-9\.!$&\'\(\)*+,;=_~:@-]|%[a-f0-9]{2})';
- $path = "(?:/$pathchar*)*";
- $querystring = '(?:\?(?:[\pL0-9\.!$&\'\(\)*+,;=_~:@/?-]|%[a-fA-F0-9]{2})*)';
- $fragment = '(?:\#(?:[\pL0-9\.!$&\'\(\)*+,;=_~:@/?-]|%[a-fA-F0-9]{2})*)';
- // Lookbehind assertions.
- // Is not HTML attribute or CSS URL property. Unfortunately legit text like "url(http://...)" will not be a link.
- $lookbehindend = "(?<![]),.;])";
- $regex = "$urlstart((?:$domainsegment\.)+$domainsegment|$numericip)" .
- "($port?$path$querystring?$fragment?)$lookbehindend";
- if ($unicoderegexp) {
- $regex = '#' . $regex . '#ui';
- } else {
- $regex = '#' . preg_replace(array('\pLl', '\PL'), 'a-z', $regex) . '#i';
- }
- // Locate any HTML tags.
- $matches = preg_split('/(<[^<|>]*>)/i', $text, -1, PREG_SPLIT_NO_EMPTY | PREG_SPLIT_DELIM_CAPTURE);
- // Iterate through the tokenized text to handle chunks (html and content).
- foreach ($matches as $idx => $chunk) {
- // Nothing to do. We skip completely any html chunk.
- if (strpos(trim($chunk), '<') === 0) {
- continue;
- }
- // Nothing to do. We skip any content chunk having any of these attributes.
- if (preg_match('#(background=")|(action=")|(style="background)|(href=")|(src=")|(url [(])#', $chunk)) {
- continue;
- }
- // Arrived here, we want to process every word in this chunk.
- $text = $chunk;
- $words = explode(' ', $text);
- foreach ($words as $idx2 => $word) {
- // ReDoS protection. Stop processing if a word is too large.
- if (strlen($word) < 4096) {
- $words[$idx2] = preg_replace($regex, '<a href="http$1://$2$3$4" class="_blanktarget">$0</a>', $word);
- }
- }
- $text = implode(' ', $words);
- // Copy the result back to the array.
- $matches[$idx] = $text;
- }
- $text = implode('', $matches);
- if (!empty($ignoretags)) {
- $ignoretags = array_reverse($ignoretags); /// Reversed so "progressive" str_replace() will solve some nesting problems.
- $text = str_replace(array_keys($ignoretags),$ignoretags,$text);
- }
- if (get_config('filter_urltolink', 'embedimages')) {
- // now try to inject the images, this code was originally in the mediapluing filter
- // this may be useful only if somebody relies on the fact the links in FORMAT_MOODLE get converted
- // to URLs which in turn change to real images
- $search = '/<a href="([^"]+\.(jpg|png|gif))" class="_blanktarget">([^>]*)<\/a>/is';
- $text = preg_replace_callback($search, 'filter_urltolink_img_callback', $text);
- }
- }
- }
- /**
- * Change links to images into embedded images.
- *
- * This plugin is intended for automatic conversion of image URLs when FORMAT_MOODLE used.
- *
- * @param $link
- * @return string
- */
- function filter_urltolink_img_callback($link) {
- if ($link[1] !== $link[3]) {
- // this is not a link created by this filter, because the url does not match the text
- return $link[0];
- }
- return '<img class="filter_urltolink_image" alt="" src="'.$link[1].'" />';
- }