backup/moodle2/backup_xml_transformer.class.php

   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  * Defines backup_xml_transformer class
  20  *
  21  * @package     core_backup
  22  * @subpackage  moodle2
  23  * @category    backup
  24  * @copyright   2010 onwards Eloy Lafuente (stronk7) {@link http://stronk7.com}
  25  * @license     http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
  26  */
  27
  28 defined('MOODLE_INTERNAL') || die();
  29
  30 // Cache for storing link encoders, so that we don't need to call
  31 // register_link_encoders each time backup_xml_transformer is constructed
  32 // TODO MDL-25290 replace global with MUC code.
  33 global $LINKS_ENCODERS_CACHE;
  34
  35 $LINKS_ENCODERS_CACHE = array();
  36
  37 /**
  38  * Class implementing the @xml_contenttransformed logic to be applied in moodle2 backups
  39  *
  40  * TODO: Finish phpdocs
  41  */
  42 class backup_xml_transformer extends xml_contenttransformer {
  43
  44     private $absolute_links_encoders; // array of static methods to be called in order to
  45                                       // perform the encoding of absolute links to all the
  46                                       // contents sent to xml
  47     private $courseid;                // courseid this content belongs to
  48     private $unicoderegexp;           // to know if the site supports unicode regexp
  49
  50     public function __construct($courseid) {
  51         $this->absolute_links_encoders = array();
  52         $this->courseid = $courseid;
  53         // Check if we support unicode modifiers in regular expressions
  54         $this->unicoderegexp = @preg_match('/\pL/u', 'a'); // This will fail silently, returning false,
  55                                                            // if regexp libraries don't support unicode
  56         // Register all the available content link encoders
  57         $this->absolute_links_encoders = $this->register_link_encoders();
  58     }
  59
  60     public function process($content) {
  61
  62         // Array or object, debug and try our best recursively, shouldn't happen but...
  63         if (is_array($content)) {
  64             debugging('Backup XML transformer should not process arrays but plain content only', DEBUG_DEVELOPER);
  65             foreach($content as $key => $plaincontent) {
  66                 $content[$key] = $this->process($plaincontent);
  67             }
  68             return $content;
  69         } else if (is_object($content)) {
  70             debugging('Backup XML transformer should not process objects but plain content only', DEBUG_DEVELOPER);
  71             foreach((array)$content as $key => $plaincontent) {
  72                 $content[$key] = $this->process($plaincontent);
  73             }
  74             return (object)$content;
  75         }
  76
  77         if (is_null($content)) {  // Some cases we know we can skip complete processing
  78             return '$@NULL@$';
  79         } else if ($content === '') {
  80             return '';
  81         } else if (is_numeric($content)) {
  82             return $content;
  83         } else if (strlen($content) < 32) { // Impossible to have one link in 32cc
  84             return $content;                // (http://10.0.0.1/file.php/1/1.jpg, http://10.0.0.1/mod/url/view.php?id=)
  85         }
  86
  87         $content = $this->process_filephp_links($content); // Replace all calls to file.php by $@FILEPHP@$ in a normalised way
  88
  89         // Replace all calls to h5p/embed.php by $@H5PEMBED@$.
  90         $content = $this->process_h5pembedphp_links($content);
  91
  92         $content = $this->encode_absolute_links($content); // Pass the content against all the found encoders
  93
  94         return $content;
  95     }
  96
  97     private function process_filephp_links($content) {
  98         global $CFG;
  99
 100         if (strpos($content, 'file.php') === false) { // No file.php, nothing to convert
 101             return $content;
 102         }
 103
 104         //First, we check for every call to file.php inside the course
 105         $search = array($CFG->wwwroot.'/file.php/' . $this->courseid,
 106                         $CFG->wwwroot.'/file.php?file=/' . $this->courseid,
 107                         $CFG->wwwroot.'/file.php?file=%2f' . $this->courseid,
 108                         $CFG->wwwroot.'/file.php?file=%2F' . $this->courseid);
 109         $replace = array('$@FILEPHP@$', '$@FILEPHP@$', '$@FILEPHP@$', '$@FILEPHP@$');
 110         $content = str_replace($search, $replace, $content);
 111
 112         // Now we look for any '$@FILEPHP@$' URLs, replacing:
 113         //     - slashes and %2F by $@SLASH@$
 114         //     - &forcedownload=1 &amp;forcedownload=1 and ?forcedownload=1 by $@FORCEDOWNLOAD@$
 115         // This way, backup contents will be neutral and independent of slasharguments configuration. MDL-18799
 116         // Based in $this->unicoderegexp, decide the regular expression to use
 117         if ($this->unicoderegexp) { //We can use unicode modifiers
 118             $search = '/(\$@FILEPHP@\$)((?:(?:\/|%2f|%2F))(?:(?:\([-;:@#&=\pL0-9\$~_.+!*\',]*?\))|[-;:@#&=\pL0-9\$~_.+!*\',]|%[a-fA-F0-9]{2}|\/)*)?(\?(?:(?:(?:\([-;:@#&=\pL0-9\$~_.+!*\',]*?\))|[-;:@#&=?\pL0-9\$~_.+!*\',]|%[a-fA-F0-9]{2}|\/)*))?(?<![,.;])/u';
 119         } else { //We cannot ue unicode modifiers
 120             $search = '/(\$@FILEPHP@\$)((?:(?:\/|%2f|%2F))(?:(?:\([-;:@#&=a-zA-Z0-9\$~_.+!*\',]*?\))|[-;:@#&=a-zA-Z0-9\$~_.+!*\',]|%[a-fA-F0-9]{2}|\/)*)?(\?(?:(?:(?:\([-;:@#&=a-zA-Z0-9\$~_.+!*\',]*?\))|[-;:@#&=?a-zA-Z0-9\$~_.+!*\',]|%[a-fA-F0-9]{2}|\/)*))?(?<![,.;])/';
 121         }
 122         $content = preg_replace_callback($search, array('backup_xml_transformer', 'process_filephp_uses'), $content);
 123
 124         return $content;
 125     }
 126
 127     /**
 128      * Replace all calls to /h5p/embed.php by $@H5PEMBED@$
 129      * to allow restore the /h5p/embed.php url in
 130      * other domains.
 131      *
 132      * @param  string $content
 133      * @return string
 134      */
 135     private function process_h5pembedphp_links($content) {
 136         global $CFG;
 137
 138         // No /h5p/embed.php, nothing to convert.
 139         if (strpos($content, '/h5p/embed.php') === false) {
 140             return $content;
 141         }
 142
 143         return str_replace($CFG->wwwroot.'/h5p/embed.php', '$@H5PEMBED@$', $content);
 144     }
 145
 146     private function encode_absolute_links($content) {
 147         foreach ($this->absolute_links_encoders as $classname => $methodname) {
 148             $content = call_user_func(array($classname, $methodname), $content);
 149         }
 150         return $content;
 151     }
 152
 153     static private function process_filephp_uses($matches) {
 154
 155         // Replace slashes (plain and encoded) and forcedownload=1 parameter
 156         $search = array('/', '%2f', '%2F', '?forcedownload=1', '&forcedownload=1', '&amp;forcedownload=1');
 157         $replace = array('$@SLASH@$', '$@SLASH@$', '$@SLASH@$', '$@FORCEDOWNLOAD@$', '$@FORCEDOWNLOAD@$', '$@FORCEDOWNLOAD@$');
 158
 159         $result = $matches[1] . (isset($matches[2]) ? str_replace($search, $replace, $matches[2]) : '') . (isset($matches[3]) ? str_replace($search, $replace, $matches[3]) : '');
 160
 161         return $result;
 162     }
 163
 164     /**
 165      * Register all available content link encoders
 166      *
 167      * @return array encoder
 168      * @todo MDL-25290 replace LINKS_ENCODERS_CACHE global with MUC code
 169      */
 170     private function register_link_encoders() {
 171         global $LINKS_ENCODERS_CACHE;
 172         // If encoder is linked, then return cached encoder.
 173         if (!empty($LINKS_ENCODERS_CACHE)) {
 174             return $LINKS_ENCODERS_CACHE;
 175         }
 176
 177         $encoders = array();
 178
 179         // Add the course encoder
 180         $encoders['backup_course_task'] = 'encode_content_links';
 181
 182         // Add the module ones. Each module supporting moodle2 backups MUST have it
 183         $mods = core_component::get_plugin_list('mod');
 184         foreach ($mods as $mod => $moddir) {
 185             if (plugin_supports('mod', $mod, FEATURE_BACKUP_MOODLE2) && class_exists('backup_' . $mod . '_activity_task')) {
 186                 $encoders['backup_' . $mod . '_activity_task'] = 'encode_content_links';
 187             }
 188         }
 189
 190         // Add the block encoders
 191         $blocks = core_component::get_plugin_list('block');
 192         foreach ($blocks as $block => $blockdir) {
 193             if (class_exists('backup_' . $block . '_block_task')) {
 194                 $encoders['backup_' . $block . '_block_task'] = 'encode_content_links';
 195             }
 196         }
 197
 198         // Add the course format encodes
 199         // TODO: Same than blocks, need to know how courseformats are going to handle backup
 200         //       (1.9 was based in backuplib function, see code)
 201
 202         // Add local encodes
 203         // TODO: Any interest? 1.9 never had that.
 204
 205         $LINKS_ENCODERS_CACHE = $encoders;
 206         return $encoders;
 207     }
 208 }