lib/filebrowser/file_browser.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
  18 /**
  19  * Utility class for browsing of files.
  20  *
  21  * @package   core_files
  22  * @copyright 2008 Petr Skoda (http://skodak.org)
  23  * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
  24  */
  25
  26 defined('MOODLE_INTERNAL') || die();
  27
  28 require_once("$CFG->libdir/filebrowser/file_info.php");
  29
  30 // general area types
  31 require_once("$CFG->libdir/filebrowser/file_info_stored.php");
  32 require_once("$CFG->libdir/filebrowser/virtual_root_file.php");
  33
  34 // description of available areas in each context level
  35 require_once("$CFG->libdir/filebrowser/file_info_context_system.php");
  36 require_once("$CFG->libdir/filebrowser/file_info_context_user.php");
  37 require_once("$CFG->libdir/filebrowser/file_info_context_coursecat.php");
  38 require_once("$CFG->libdir/filebrowser/file_info_context_course.php");
  39 require_once("$CFG->libdir/filebrowser/file_info_context_module.php");
  40
  41 /**
  42  * This class provides the main entry point for other code wishing to get information about files.
  43  *
  44  * The whole file storage for a Moodle site can be seen as a huge virtual tree.
  45  * The spine of the tree is the tree of contexts (system, course-categories,
  46  * courses, modules, also users). Then, within each context, there may be any number of
  47  * file areas, and a file area contains folders and files. The various file_info
  48  * subclasses return info about the things in this tree. They should be obtained
  49  * from an instance of this class.
  50  *
  51  * This virtual tree is different for each user depending of his/her current permissions.
  52  * Some branches such as draft areas are hidden, but accessible.
  53  *
  54  * Always use this abstraction when you need to access module files from core code.
  55   *
  56  * @package   core_files
  57  * @category  files
  58  * @copyright 2008 Petr Skoda (http://skodak.org)
  59  * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
  60 */
  61 class file_browser {
  62
  63     /**
  64      * Looks up file_info instance
  65      *
  66      * @param stdClass $context context object
  67      * @param string $component component
  68      * @param string $filearea file area
  69      * @param int $itemid item ID
  70      * @param string $filepath file path
  71      * @param string $filename file name
  72      * @return file_info|null file_info instance or null if not found or access not allowed
  73      */
  74     public function get_file_info($context = NULL, $component = NULL, $filearea = NULL, $itemid = NULL, $filepath = NULL, $filename = NULL) {
  75         if (!$context) {
  76             $context = context_system::instance();
  77         }
  78         switch ($context->contextlevel) {
  79             case CONTEXT_SYSTEM:
  80                 return $this->get_file_info_context_system($context, $component, $filearea, $itemid, $filepath, $filename);
  81             case CONTEXT_USER:
  82                 return $this->get_file_info_context_user($context, $component, $filearea, $itemid, $filepath, $filename);
  83             case CONTEXT_COURSECAT:
  84                 return $this->get_file_info_context_coursecat($context, $component, $filearea, $itemid, $filepath, $filename);
  85             case CONTEXT_COURSE:
  86                 return $this->get_file_info_context_course($context, $component, $filearea, $itemid, $filepath, $filename);
  87             case CONTEXT_MODULE:
  88                 return $this->get_file_info_context_module($context, $component, $filearea, $itemid, $filepath, $filename);
  89         }
  90
  91         return null;
  92     }
  93
  94     /**
  95      * Returns info about the files at System context
  96      * @todo MDL-33372 - Provide a way of displaying recent files for blog entries.
  97      *
  98      * @param object $context context object
  99      * @param string $component component
 100      * @param string $filearea file area
 101      * @param int $itemid item ID
 102      * @param string $filepath file path
 103      * @param string $filename file name
 104      * @return file_info instance or null if not found or access not allowed
 105      */
 106     private function get_file_info_context_system($context, $component, $filearea, $itemid, $filepath, $filename) {
 107         $level = new file_info_context_system($this, $context);
 108         return $level->get_file_info($component, $filearea, $itemid, $filepath, $filename);
 109         // nothing supported at this context yet
 110     }
 111
 112     /**
 113      * Returns info about the files at User context
 114      *
 115      * @param stdClass $context context object
 116      * @param string $component component
 117      * @param string $filearea file area
 118      * @param int $itemid item ID
 119      * @param string $filepath file path
 120      * @param string $filename file name
 121      * @return file_info|null file_info instance or null if not found or access not allowed
 122      */
 123     private function get_file_info_context_user($context, $component, $filearea, $itemid, $filepath, $filename) {
 124         global $DB, $USER;
 125         if ($context->instanceid == $USER->id) {
 126             $user = $USER;
 127         } else {
 128             $user = $DB->get_record('user', array('id'=>$context->instanceid));
 129         }
 130
 131         if (isguestuser($user)) {
 132             // guests do not have any files
 133             return null;
 134         }
 135
 136         if ($user->deleted) {
 137             return null;
 138         }
 139
 140         $level = new file_info_context_user($this, $context, $user);
 141         return $level->get_file_info($component, $filearea, $itemid, $filepath, $filename);
 142     }
 143
 144     /**
 145      * Returns info about the files at Course category context
 146      *
 147      * @param stdClass $context context object
 148      * @param string $component component
 149      * @param string $filearea file area
 150      * @param int $itemid item ID
 151      * @param string $filepath file path
 152      * @param string $filename file name
 153      * @return file_info|null file_info instance or null if not found or access not allowed
 154      */
 155     private function get_file_info_context_coursecat($context, $component, $filearea, $itemid, $filepath, $filename) {
 156         global $DB;
 157
 158         if (!$category = $DB->get_record('course_categories', array('id'=>$context->instanceid))) {
 159             return null;
 160         }
 161
 162         $level = new file_info_context_coursecat($this, $context, $category);
 163         return $level->get_file_info($component, $filearea, $itemid, $filepath, $filename);
 164     }
 165
 166     /**
 167      * Returns info about the files at Course category context
 168      *
 169      * @param stdClass $context context object
 170      * @param string $component component
 171      * @param string $filearea file area
 172      * @param int $itemid item ID
 173      * @param string $filepath file path
 174      * @param string $filename file name
 175      * @return file_info|null file_info instance or null if not found or access not allowed
 176      */
 177     private function get_file_info_context_course($context, $component, $filearea, $itemid, $filepath, $filename) {
 178         global $DB, $COURSE;
 179
 180         if ($context->instanceid == $COURSE->id) {
 181             $course = $COURSE;
 182         } else if (!$course = $DB->get_record('course', array('id'=>$context->instanceid))) {
 183             return null;
 184         }
 185
 186         $level = new file_info_context_course($this, $context, $course);
 187         return $level->get_file_info($component, $filearea, $itemid, $filepath, $filename);
 188     }
 189
 190     /**
 191      * Returns info about the files at Course category context
 192      *
 193      * @param stdClass $context context object
 194      * @param string $component component
 195      * @param string $filearea file area
 196      * @param int $itemid item ID
 197      * @param string $filepath file path
 198      * @param string $filename file name
 199      * @return file_info|null file_info instance or null if not found or access not allowed
 200      */
 201     private function get_file_info_context_module($context, $component, $filearea, $itemid, $filepath, $filename) {
 202         global $COURSE, $DB, $CFG;
 203
 204         static $cachedmodules = array();
 205
 206         if (!array_key_exists($context->instanceid, $cachedmodules)) {
 207             $cachedmodules[$context->instanceid] = get_coursemodule_from_id('', $context->instanceid);
 208         }
 209
 210         if (!($cm = $cachedmodules[$context->instanceid])) {
 211             return null;
 212         }
 213
 214         if ($cm->course == $COURSE->id) {
 215             $course = $COURSE;
 216         } else if (!$course = $DB->get_record('course', array('id'=>$cm->course))) {
 217             return null;
 218         }
 219
 220         $modinfo = get_fast_modinfo($course);
 221         if (empty($modinfo->cms[$cm->id]->uservisible)) {
 222             return null;
 223         }
 224
 225         $modname = $modinfo->cms[$cm->id]->modname;
 226
 227         if (!file_exists("$CFG->dirroot/mod/$modname/lib.php")) {
 228             return null;
 229         }
 230
 231         // ok, we know that module exists, and user may access it
 232
 233         $level = new file_info_context_module($this, $context, $course, $cm, $modname);
 234         return $level->get_file_info($component, $filearea, $itemid, $filepath, $filename);
 235     }
 236
 237 }