source: moodle/trunk/fuentes/filter/urltolink/filter.php @ 136

Last change on this file since 136 was 136, checked in by mabarracus, 3 years ago

Ported code to xenial

File size: 7.1 KB
Line 
1<?php
2
3// This file is part of Moodle - http://moodle.org/
4//
5// Moodle is free software: you can redistribute it and/or modify
6// it under the terms of the GNU General Public License as published by
7// the Free Software Foundation, either version 3 of the License, or
8// (at your option) any later version.
9//
10// Moodle is distributed in the hope that it will be useful,
11// but WITHOUT ANY WARRANTY; without even the implied warranty of
12// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
13// GNU General Public License for more details.
14//
15// You should have received a copy of the GNU General Public License
16// along with Moodle.  If not, see <http://www.gnu.org/licenses/>.
17
18/**
19 * Filter converting URLs in the text to HTML links
20 *
21 * @package    filter
22 * @subpackage urltolink
23 * @copyright  2010 David Mudrak <david@moodle.com>
24 * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
25 */
26
27defined('MOODLE_INTERNAL') || die();
28
29class filter_urltolink extends moodle_text_filter {
30
31    /**
32     * @var array global configuration for this filter
33     *
34     * This might be eventually moved into parent class if we found it
35     * useful for other filters, too.
36     */
37    protected static $globalconfig;
38
39    /**
40     * Apply the filter to the text
41     *
42     * @see filter_manager::apply_filter_chain()
43     * @param string $text to be processed by the text
44     * @param array $options filter options
45     * @return string text after processing
46     */
47    public function filter($text, array $options = array()) {
48        if (!isset($options['originalformat'])) {
49            // if the format is not specified, we are probably called by {@see format_string()}
50            // in that case, it would be dangerous to replace URL with the link because it could
51            // be stripped. therefore, we do nothing
52            return $text;
53        }
54        if (in_array($options['originalformat'], explode(',', $this->get_global_config('formats')))) {
55            $this->convert_urls_into_links($text);
56        }
57        return $text;
58    }
59
60    ////////////////////////////////////////////////////////////////////////////
61    // internal implementation starts here
62    ////////////////////////////////////////////////////////////////////////////
63
64    /**
65     * Returns the global filter setting
66     *
67     * If the $name is provided, returns single value. Otherwise returns all
68     * global settings in object. Returns null if the named setting is not
69     * found.
70     *
71     * @param mixed $name optional config variable name, defaults to null for all
72     * @return string|object|null
73     */
74    protected function get_global_config($name=null) {
75        $this->load_global_config();
76        if (is_null($name)) {
77            return self::$globalconfig;
78
79        } elseif (array_key_exists($name, self::$globalconfig)) {
80            return self::$globalconfig->{$name};
81
82        } else {
83            return null;
84        }
85    }
86
87    /**
88     * Makes sure that the global config is loaded in $this->globalconfig
89     *
90     * @return void
91     */
92    protected function load_global_config() {
93        if (is_null(self::$globalconfig)) {
94            self::$globalconfig = get_config('filter_urltolink');
95        }
96    }
97
98    /**
99     * Given some text this function converts any URLs it finds into HTML links
100     *
101     * @param string $text Passed in by reference. The string to be searched for urls.
102     */
103    protected function convert_urls_into_links(&$text) {
104        //I've added img tags to this list of tags to ignore.
105        //See MDL-21168 for more info. A better way to ignore tags whether or not
106        //they are escaped partially or completely would be desirable. For example:
107        //<a href="blah">
108        //&lt;a href="blah"&gt;
109        //&lt;a href="blah">
110        $filterignoretagsopen  = array('<a\s[^>]+?>');
111        $filterignoretagsclose = array('</a>');
112        filter_save_ignore_tags($text,$filterignoretagsopen,$filterignoretagsclose,$ignoretags);
113
114        // Check if we support unicode modifiers in regular expressions. Cache it.
115        // TODO: this check should be a environment requirement in Moodle 2.0, as far as unicode
116        // chars are going to arrive to URLs officially really soon (2010?)
117        // Original RFC regex from: http://www.bytemycode.com/snippets/snippet/796/
118        // Various ideas from: http://alanstorm.com/url_regex_explained
119        // Unicode check, negative assertion and other bits from Moodle.
120        static $unicoderegexp;
121        if (!isset($unicoderegexp)) {
122            $unicoderegexp = @preg_match('/\pL/u', 'a'); // This will fail silently, returning false,
123        }
124
125        // TODO MDL-21296 - use of unicode modifiers may cause a timeout
126        $urlstart = '(?:http(s)?://|(?<!://)(www\.))';
127        $domainsegment = '(?:[\pLl0-9][\pLl0-9-]*[\pLl0-9]|[\pLl0-9])';
128        $numericip = '(?:(?:[0-9]{1,3}\.){3}[0-9]{1,3})';
129        $port = '(?::\d*)';
130        $pathchar = '(?:[\pL0-9\.!$&\'\(\)*+,;=_~:@-]|%[a-f0-9]{2})';
131        $path = "(?:/$pathchar*)*";
132        $querystring = '(?:\?(?:[\pL0-9\.!$&\'\(\)*+,;=_~:@/?-]|%[a-fA-F0-9]{2})*)';
133        $fragment = '(?:\#(?:[\pL0-9\.!$&\'\(\)*+,;=_~:@/?-]|%[a-fA-F0-9]{2})*)';
134
135        // Lookbehind assertions.
136        // Is not HTML attribute or CSS URL property. Unfortunately legit text like "url(http://...)" will not be a link.
137        $lookbehindstart = "(?<!=[\"']|\burl\([\"' ]|\burl\()";
138        $lookbehindend = "(?<![]),.;])";
139
140        $regex = "$lookbehindstart$urlstart((?:$domainsegment\.)+$domainsegment|$numericip)" .
141                "($port?$path$querystring?$fragment?)$lookbehindend";
142        if ($unicoderegexp) {
143            $regex = '#' . $regex . '#ui';
144        } else {
145            $regex = '#' . preg_replace(array('\pLl', '\PL'), 'a-z', $regex) . '#i';
146        }
147
148        $text = preg_replace($regex, '<a href="http$1://$2$3$4" class="_blanktarget">$0</a>', $text);
149
150        if (!empty($ignoretags)) {
151            $ignoretags = array_reverse($ignoretags); /// Reversed so "progressive" str_replace() will solve some nesting problems.
152            $text = str_replace(array_keys($ignoretags),$ignoretags,$text);
153        }
154
155        if ($this->get_global_config('embedimages')) {
156            // now try to inject the images, this code was originally in the mediapluing filter
157            // this may be useful only if somebody relies on the fact the links in FORMAT_MOODLE get converted
158            // to URLs which in turn change to real images
159            $search = '/<a href="([^"]+\.(jpg|png|gif))" class="_blanktarget">([^>]*)<\/a>/is';
160            $text = preg_replace_callback($search, 'filter_urltolink_img_callback', $text);
161        }
162    }
163}
164
165
166/**
167 * Change links to images into embedded images.
168 *
169 * This plugin is intended for automatic conversion of image URLs when FORMAT_MOODLE used.
170 *
171 * @param  $link
172 * @return string
173 */
174function filter_urltolink_img_callback($link) {
175    if ($link[1] !== $link[3]) {
176        // this is not a link created by this filter, because the url does not match the text
177        return $link[0];
178    }
179    return '<img class="filter_urltolink_image" alt="" src="'.$link[1].'" />';
180}
181
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