moodle/lib/filebrowser/file_browser.php
2012-02-15 12:48:57 +08:00

232 lines
8.9 KiB
PHP

<?php
// This file is part of Moodle - http://moodle.org/
//
// Moodle is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// Moodle is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with Moodle. If not, see <http://www.gnu.org/licenses/>.
/**
* Utility class for browsing of files.
*
* @package core_files
* @copyright 2008 Petr Skoda (http://skodak.org)
* @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
*/
defined('MOODLE_INTERNAL') || die();
require_once("$CFG->libdir/filebrowser/file_info.php");
// general area types
require_once("$CFG->libdir/filebrowser/file_info_stored.php");
require_once("$CFG->libdir/filebrowser/virtual_root_file.php");
// description of available areas in each context level
require_once("$CFG->libdir/filebrowser/file_info_context_system.php");
require_once("$CFG->libdir/filebrowser/file_info_context_user.php");
require_once("$CFG->libdir/filebrowser/file_info_context_coursecat.php");
require_once("$CFG->libdir/filebrowser/file_info_context_course.php");
require_once("$CFG->libdir/filebrowser/file_info_context_module.php");
/**
* This class provides the main entry point for other code wishing to get information about files.
*
* The whole file storage for a Moodle site can be seen as a huge virtual tree.
* The spine of the tree is the tree of contexts (system, course-categories,
* courses, modules, also users). Then, within each context, there may be any number of
* file areas, and a file area contains folders and files. The various file_info
* subclasses return info about the things in this tree. They should be obtained
* from an instance of this class.
*
* This virtual tree is different for each user depending of his/her current permissions.
* Some branches such as draft areas are hidden, but accessible.
*
* Always use this abstraction when you need to access module files from core code.
*
* @package core_files
* @category files
* @copyright 2008 Petr Skoda (http://skodak.org)
* @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
*/
class file_browser {
/**
* Looks up file_info instance
*
* @param stdClass $context context object
* @param string $component component
* @param string $filearea file area
* @param int $itemid item ID
* @param string $filepath file path
* @param string $filename file name
* @return file_info|null file_info instance or null if not found or access not allowed
*/
public function get_file_info($context = NULL, $component = NULL, $filearea = NULL, $itemid = NULL, $filepath = NULL, $filename = NULL) {
if (!$context) {
$context = get_context_instance(CONTEXT_SYSTEM);
}
switch ($context->contextlevel) {
case CONTEXT_SYSTEM:
return $this->get_file_info_context_system($context, $component, $filearea, $itemid, $filepath, $filename);
case CONTEXT_USER:
return $this->get_file_info_context_user($context, $component, $filearea, $itemid, $filepath, $filename);
case CONTEXT_COURSECAT:
return $this->get_file_info_context_coursecat($context, $component, $filearea, $itemid, $filepath, $filename);
case CONTEXT_COURSE:
return $this->get_file_info_context_course($context, $component, $filearea, $itemid, $filepath, $filename);
case CONTEXT_MODULE:
return $this->get_file_info_context_module($context, $component, $filearea, $itemid, $filepath, $filename);
}
return null;
}
/**
* Returns info about the files at System context
*
* @param object $context context object
* @param string $component component
* @param string $filearea file area
* @param int $itemid item ID
* @param string $filepath file path
* @param string $filename file name
* @return file_info instance or null if not found or access not allowed
*/
private function get_file_info_context_system($context, $component, $filearea, $itemid, $filepath, $filename) {
$level = new file_info_context_system($this, $context);
return $level->get_file_info($component, $filearea, $itemid, $filepath, $filename);
// nothing supported at this context yet
}
/**
* Returns info about the files at User context
*
* @param stdClass $context context object
* @param string $component component
* @param string $filearea file area
* @param int $itemid item ID
* @param string $filepath file path
* @param string $filename file name
* @return file_info|null file_info instance or null if not found or access not allowed
*/
private function get_file_info_context_user($context, $component, $filearea, $itemid, $filepath, $filename) {
global $DB, $USER;
if ($context->instanceid == $USER->id) {
$user = $USER;
} else {
$user = $DB->get_record('user', array('id'=>$context->instanceid));
}
if (isguestuser($user)) {
// guests do not have any files
return null;
}
if ($user->deleted) {
return null;
}
$level = new file_info_context_user($this, $context, $user);
return $level->get_file_info($component, $filearea, $itemid, $filepath, $filename);
}
/**
* Returns info about the files at Course category context
*
* @param stdClass $context context object
* @param string $component component
* @param string $filearea file area
* @param int $itemid item ID
* @param string $filepath file path
* @param string $filename file name
* @return file_info|null file_info instance or null if not found or access not allowed
*/
private function get_file_info_context_coursecat($context, $component, $filearea, $itemid, $filepath, $filename) {
global $DB;
if (!$category = $DB->get_record('course_categories', array('id'=>$context->instanceid))) {
return null;
}
$level = new file_info_context_coursecat($this, $context, $category);
return $level->get_file_info($component, $filearea, $itemid, $filepath, $filename);
}
/**
* Returns info about the files at Course category context
*
* @param stdClass $context context object
* @param string $component component
* @param string $filearea file area
* @param int $itemid item ID
* @param string $filepath file path
* @param string $filename file name
* @return file_info|null file_info instance or null if not found or access not allowed
*/
private function get_file_info_context_course($context, $component, $filearea, $itemid, $filepath, $filename) {
global $DB, $COURSE;
if ($context->instanceid == $COURSE->id) {
$course = $COURSE;
} else if (!$course = $DB->get_record('course', array('id'=>$context->instanceid))) {
return null;
}
$level = new file_info_context_course($this, $context, $course);
return $level->get_file_info($component, $filearea, $itemid, $filepath, $filename);
}
/**
* Returns info about the files at Course category context
*
* @param stdClass $context context object
* @param string $component component
* @param string $filearea file area
* @param int $itemid item ID
* @param string $filepath file path
* @param string $filename file name
* @return file_info|null file_info instance or null if not found or access not allowed
*/
private function get_file_info_context_module($context, $component, $filearea, $itemid, $filepath, $filename) {
global $COURSE, $DB, $CFG;
if (!$cm = get_coursemodule_from_id('', $context->instanceid)) {
return null;
}
if ($cm->course == $COURSE->id) {
$course = $COURSE;
} else if (!$course = $DB->get_record('course', array('id'=>$cm->course))) {
return null;
}
$modinfo = get_fast_modinfo($course);
if (empty($modinfo->cms[$cm->id]->uservisible)) {
return null;
}
$modname = $modinfo->cms[$cm->id]->modname;
if (!file_exists("$CFG->dirroot/mod/$modname/lib.php")) {
return null;
}
// ok, we know that module exists, and user may access it
$level = new file_info_context_module($this, $context, $course, $cm, $modname);
return $level->get_file_info($component, $filearea, $itemid, $filepath, $filename);
}
}