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<?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 nothingreturn $text;}if (in_array($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">$filterignoretagsopen = array('<a\s[^>]+?>', '<span[^>]+?class="nolink"[^>]*?>');$filterignoretagsclose = array('</a>', '</span>');$ignoretags = [];filter_save_ignore_tags($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 textreturn $link[0];}return '<img class="filter_urltolink_image" alt="" src="'.$link[1].'" />';}