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     /** @var array cached list of enrolled courses.  */
  64     protected $enrolledcourses = null;
  65
  66     /**
  67      * Looks up file_info instance
  68      *
  69      * @param stdClass $context context object
  70      * @param string $component component
  71      * @param string $filearea file area
  72      * @param int $itemid item ID
  73      * @param string $filepath file path
  74      * @param string $filename file name
  75      * @return file_info|null file_info instance or null if not found or access not allowed
  76      */
  77     public function get_file_info($context = NULL, $component = NULL, $filearea = NULL, $itemid = NULL, $filepath = NULL, $filename = NULL) {
  78         if (!$context) {
  79             $context = context_system::instance();
  80         }
  81         switch ($context->contextlevel) {
  82             case CONTEXT_SYSTEM:
  83                 return $this->get_file_info_context_system($context, $component, $filearea, $itemid, $filepath, $filename);
  84             case CONTEXT_USER:
  85                 return $this->get_file_info_context_user($context, $component, $filearea, $itemid, $filepath, $filename);
  86             case CONTEXT_COURSECAT:
  87                 return $this->get_file_info_context_coursecat($context, $component, $filearea, $itemid, $filepath, $filename);
  88             case CONTEXT_COURSE:
  89                 return $this->get_file_info_context_course($context, $component, $filearea, $itemid, $filepath, $filename);
  90             case CONTEXT_MODULE:
  91                 return $this->get_file_info_context_module($context, $component, $filearea, $itemid, $filepath, $filename);
  92         }
  93
  94         return null;
  95     }
  96
  97     /**
  98      * Returns info about the files at System context
  99      * @todo MDL-33372 - Provide a way of displaying recent files for blog entries.
 100      *
 101      * @param object $context context object
 102      * @param string $component component
 103      * @param string $filearea file area
 104      * @param int $itemid item ID
 105      * @param string $filepath file path
 106      * @param string $filename file name
 107      * @return file_info instance or null if not found or access not allowed
 108      */
 109     private function get_file_info_context_system($context, $component, $filearea, $itemid, $filepath, $filename) {
 110         $level = new file_info_context_system($this, $context);
 111         return $level->get_file_info($component, $filearea, $itemid, $filepath, $filename);
 112         // nothing supported at this context yet
 113     }
 114
 115     /**
 116      * Returns info about the files at User context
 117      *
 118      * @param stdClass $context context object
 119      * @param string $component component
 120      * @param string $filearea file area
 121      * @param int $itemid item ID
 122      * @param string $filepath file path
 123      * @param string $filename file name
 124      * @return file_info|null file_info instance or null if not found or access not allowed
 125      */
 126     private function get_file_info_context_user($context, $component, $filearea, $itemid, $filepath, $filename) {
 127         global $DB, $USER;
 128         if ($context->instanceid == $USER->id) {
 129             $user = $USER;
 130         } else {
 131             $user = $DB->get_record('user', array('id'=>$context->instanceid));
 132         }
 133
 134         if (isguestuser($user)) {
 135             // guests do not have any files
 136             return null;
 137         }
 138
 139         if ($user->deleted) {
 140             return null;
 141         }
 142
 143         $level = new file_info_context_user($this, $context, $user);
 144         return $level->get_file_info($component, $filearea, $itemid, $filepath, $filename);
 145     }
 146
 147     /**
 148      * Returns info about the files at Course category context
 149      *
 150      * @param stdClass $context context object
 151      * @param string $component component
 152      * @param string $filearea file area
 153      * @param int $itemid item ID
 154      * @param string $filepath file path
 155      * @param string $filename file name
 156      * @return file_info|null file_info instance or null if not found or access not allowed
 157      */
 158     private function get_file_info_context_coursecat($context, $component, $filearea, $itemid, $filepath, $filename) {
 159         global $DB;
 160
 161         if (!$category = $DB->get_record('course_categories', array('id'=>$context->instanceid))) {
 162             return null;
 163         }
 164
 165         $level = new file_info_context_coursecat($this, $context, $category);
 166         return $level->get_file_info($component, $filearea, $itemid, $filepath, $filename);
 167     }
 168
 169     /**
 170      * Returns info about the files at Course category context
 171      *
 172      * @param stdClass $context context object
 173      * @param string $component component
 174      * @param string $filearea file area
 175      * @param int $itemid item ID
 176      * @param string $filepath file path
 177      * @param string $filename file name
 178      * @return file_info|null file_info instance or null if not found or access not allowed
 179      */
 180     private function get_file_info_context_course($context, $component, $filearea, $itemid, $filepath, $filename) {
 181         global $DB, $COURSE;
 182
 183         if ($context->instanceid == $COURSE->id) {
 184             $course = $COURSE;
 185         } else if (!$course = $DB->get_record('course', array('id'=>$context->instanceid))) {
 186             return null;
 187         }
 188
 189         $level = new file_info_context_course($this, $context, $course);
 190         return $level->get_file_info($component, $filearea, $itemid, $filepath, $filename);
 191     }
 192
 193     /**
 194      * Returns info about the files at Course category context
 195      *
 196      * @param context $context context object
 197      * @param string $component component
 198      * @param string $filearea file area
 199      * @param int $itemid item ID
 200      * @param string $filepath file path
 201      * @param string $filename file name
 202      * @return file_info|null file_info instance or null if not found or access not allowed
 203      */
 204     private function get_file_info_context_module($context, $component, $filearea, $itemid, $filepath, $filename) {
 205         if (!($context instanceof context_module)) {
 206             return null;
 207         }
 208         $coursecontext = $context->get_course_context();
 209         $modinfo = get_fast_modinfo($coursecontext->instanceid);
 210         $cm = $modinfo->get_cm($context->instanceid);
 211
 212         if (empty($cm->uservisible)) {
 213             return null;
 214         }
 215
 216         $level = new file_info_context_module($this, $context, $cm->get_course(), $cm, $cm->modname);
 217         return $level->get_file_info($component, $filearea, $itemid, $filepath, $filename);
 218     }
 219
 220     /**
 221      * Check if user is enrolled into the course
 222      *
 223      * This function keeps a cache of enrolled courses because it may be called multiple times for many courses in one request
 224      *
 225      * @param int $courseid
 226      * @return bool
 227      */
 228     public function is_enrolled($courseid) {
 229         if ($this->enrolledcourses === null || PHPUNIT_TEST) {
 230             // Since get_file_browser() returns a statically cached object we can't rely on cache
 231             // inside the file_browser class in the unittests.
 232             // TODO MDL-59964 remove this caching when it's implemented inside enrol_get_my_courses().
 233             $this->enrolledcourses = enrol_get_my_courses(['id']);
 234         }
 235         return array_key_exists($courseid, $this->enrolledcourses);
 236     }
 237 }