lib/filebrowser/file_browser.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 /**
  20  * Utility class for browsing of files.
  21  *
  22  * @package    core
  23  * @subpackage filebrowser
  24  * @copyright  2008 Petr Skoda (http://skodak.org)
  25  * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
  26  */
  27
  28 defined('MOODLE_INTERNAL') || die();
  29
  30 require_once("$CFG->libdir/filebrowser/file_info.php");
  31
  32 // general area types
  33 require_once("$CFG->libdir/filebrowser/file_info_stored.php");
  34 require_once("$CFG->libdir/filebrowser/virtual_root_file.php");
  35
  36 // description of available areas in each context level
  37 require_once("$CFG->libdir/filebrowser/file_info_context_system.php");
  38 require_once("$CFG->libdir/filebrowser/file_info_context_user.php");
  39 require_once("$CFG->libdir/filebrowser/file_info_context_coursecat.php");
  40 require_once("$CFG->libdir/filebrowser/file_info_context_course.php");
  41 require_once("$CFG->libdir/filebrowser/file_info_context_module.php");
  42
  43 /**
  44  * This class provides the main entry point for other code wishing to get
  45  * information about files.
  46  *
  47  * The whole file storage for a Moodle site can be seen as a huge virtual tree.
  48  * The spine of the tree is the tree of contexts (system, course-categories,
  49  * courses, modules, also users). Then, within each context, there may be any number of
  50  * file areas, and a file area contains folders and files. The various file_info
  51  * subclasses return info about the things in this tree. They should be obtained
  52  * from an instance of this class.
  53  *
  54  * This virtual tree is different for each user depending of his/her current permissions.
  55  * Some branches such as draft areas are hidden, but accessible.
  56  *
  57  * Always use this abstraction when you need to access module files from core code.
  58   *
  59  * @package    core
  60  * @subpackage filebrowser
  61  * @copyright  2008 Petr Skoda (http://skodak.org)
  62  * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
  63 */
  64 class file_browser {
  65
  66     /**
  67      * Looks up file_info instance
  68      * @param object $context
  69      * @param string $component
  70      * @param string $filearea
  71      * @param int $itemid
  72      * @param string $filepath
  73      * @param string $filename
  74      * @return file_info instance or null if not found or access not allowed
  75      */
  76     public function get_file_info($context = NULL, $component = NULL, $filearea = NULL, $itemid = NULL, $filepath = NULL, $filename = NULL) {
  77         if (!$context) {
  78             $context = get_context_instance(CONTEXT_SYSTEM);
  79         }
  80         switch ($context->contextlevel) {
  81             case CONTEXT_SYSTEM:
  82                 return $this->get_file_info_context_system($context, $component, $filearea, $itemid, $filepath, $filename);
  83             case CONTEXT_USER:
  84                 return $this->get_file_info_context_user($context, $component, $filearea, $itemid, $filepath, $filename);
  85             case CONTEXT_COURSECAT:
  86                 return $this->get_file_info_context_coursecat($context, $component, $filearea, $itemid, $filepath, $filename);
  87             case CONTEXT_COURSE:
  88                 return $this->get_file_info_context_course($context, $component, $filearea, $itemid, $filepath, $filename);
  89             case CONTEXT_MODULE:
  90                 return $this->get_file_info_context_module($context, $component, $filearea, $itemid, $filepath, $filename);
  91         }
  92
  93         return null;
  94     }
  95
  96     /**
  97      * Returns info about the files at System context
  98      * @param object $context
  99      * @param string $component
 100      * @param string $filearea
 101      * @param int $itemid
 102      * @param string $filepath
 103      * @param string $filename
 104      * @return file_info instance or null if not found or access not allowed
 105      */
 106     private function get_file_info_context_system($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      * @param object $context
 115      * @param string $component
 116      * @param string $filearea
 117      * @param int $itemid
 118      * @param string $filepath
 119      * @param string $filename
 120      * @return file_info instance or null if not found or access not allowed
 121      */
 122     private function get_file_info_context_user($context, $component, $filearea, $itemid, $filepath, $filename) {
 123         global $DB, $USER;
 124         if ($context->instanceid == $USER->id) {
 125             $user = $USER;
 126         } else {
 127             $user = $DB->get_record('user', array('id'=>$context->instanceid));
 128         }
 129
 130         if (isguestuser($user)) {
 131             // guests do not have any files
 132             return null;
 133         }
 134
 135         if ($user->deleted) {
 136             return null;
 137         }
 138
 139         $level = new file_info_context_user($this, $context, $user);
 140         return $level->get_file_info($component, $filearea, $itemid, $filepath, $filename);
 141     }
 142
 143     /**
 144      * Returns info about the files at Course category context
 145      * @param object $context
 146      * @param string $component
 147      * @param string $filearea
 148      * @param int $itemid
 149      * @param string $filepath
 150      * @param string $filename
 151      * @return file_info instance or null if not found or access not allowed
 152      */
 153     private function get_file_info_context_coursecat($context, $component, $filearea, $itemid, $filepath, $filename) {
 154         global $DB;
 155
 156         if (!$category = $DB->get_record('course_categories', array('id'=>$context->instanceid))) {
 157             return null;
 158         }
 159
 160         $level = new file_info_context_coursecat($this, $context, $category);
 161         return $level->get_file_info($component, $filearea, $itemid, $filepath, $filename);
 162     }
 163
 164     /**
 165      * Returns info about the files at Course category context
 166      * @param object $context
 167      * @param string $component
 168      * @param string $filearea
 169      * @param int $itemid
 170      * @param string $filepath
 171      * @param string $filename
 172      * @return file_info instance or null if not found or access not allowed
 173      */
 174     private function get_file_info_context_course($context, $component, $filearea, $itemid, $filepath, $filename) {
 175         global $DB, $COURSE;
 176
 177         if ($context->instanceid == $COURSE->id) {
 178             $course = $COURSE;
 179         } else if (!$course = $DB->get_record('course', array('id'=>$context->instanceid))) {
 180             return null;
 181         }
 182
 183         $level = new file_info_context_course($this, $context, $course);
 184         return $level->get_file_info($component, $filearea, $itemid, $filepath, $filename);
 185     }
 186
 187     /**
 188      * Returns info about the files at Course category context
 189      * @param object $context
 190      * @param string $component
 191      * @param string $filearea
 192      * @param int $itemid
 193      * @param string $filepath
 194      * @param string $filename
 195      * @return file_info instance or null if not found or access not allowed
 196      */
 197     private function get_file_info_context_module($context, $component, $filearea, $itemid, $filepath, $filename) {
 198         global $COURSE, $DB, $CFG;
 199
 200
 201         if (!$cm = get_coursemodule_from_id('', $context->instanceid)) {
 202             return null;
 203         }
 204
 205         if ($cm->course == $COURSE->id) {
 206             $course = $COURSE;
 207         } else if (!$course = $DB->get_record('course', array('id'=>$cm->course))) {
 208             return null;
 209         }
 210
 211         $modinfo = get_fast_modinfo($course);
 212         if (empty($modinfo->cms[$cm->id]->uservisible)) {
 213             return null;
 214         }
 215
 216         $modname = $modinfo->cms[$cm->id]->modname;
 217
 218         if (!file_exists("$CFG->dirroot/mod/$modname/lib.php")) {
 219             return null;
 220         }
 221
 222         // ok, we know that module exists, and user may access it
 223
 224         $level = new file_info_context_module($this, $context, $course, $cm, $modname);
 225         return $level->get_file_info($component, $filearea, $itemid, $filepath, $filename);
 226     }
 227
 228 }