pluginfile.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  * This script delegates file serving to individual plugins
  20  *
  21  * @package    core
  22  * @subpackage file
  23  * @copyright  2008 Petr Skoda (http://skodak.org)
  24  * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
  25  */
  26
  27 // disable moodle specific debug messages and any errors in output
  28 //define('NO_DEBUG_DISPLAY', true);
  29 //TODO: uncomment this once the file api stabilises a bit more
  30
  31 require_once('config.php');
  32 require_once('lib/filelib.php');
  33
  34 $relativepath = get_file_argument();
  35 $forcedownload = optional_param('forcedownload', 0, PARAM_BOOL);
  36
  37 // relative path must start with '/'
  38 if (!$relativepath) {
  39     print_error('invalidargorconf');
  40 } else if ($relativepath[0] != '/') {
  41     print_error('pathdoesnotstartslash');
  42 }
  43
  44 // extract relative path components
  45 $args = explode('/', ltrim($relativepath, '/'));
  46
  47 if (count($args) < 3) { // always at least context, component and filearea
  48     print_error('invalidarguments');
  49 }
  50
  51 $contextid = (int)array_shift($args);
  52 $component = clean_param(array_shift($args), PARAM_COMPONENT);
  53 $filearea  = clean_param(array_shift($args), PARAM_AREA);
  54
  55 list($context, $course, $cm) = get_context_info_array($contextid);
  56
  57 $fs = get_file_storage();
  58
  59 // ========================================================================================================================
  60 if ($component === 'blog') {
  61     // Blog file serving
  62     if ($context->contextlevel != CONTEXT_SYSTEM) {
  63         send_file_not_found();
  64     }
  65     if ($filearea !== 'attachment' and $filearea !== 'post') {
  66         send_file_not_found();
  67     }
  68
  69     if (empty($CFG->bloglevel)) {
  70         print_error('siteblogdisable', 'blog');
  71     }
  72
  73     if ($CFG->bloglevel < BLOG_GLOBAL_LEVEL) {
  74         require_login();
  75         if (isguestuser()) {
  76             print_error('noguest');
  77         }
  78         if ($CFG->bloglevel == BLOG_USER_LEVEL) {
  79             if ($USER->id != $entry->userid) {
  80                 send_file_not_found();
  81             }
  82         }
  83     }
  84     $entryid = (int)array_shift($args);
  85     if (!$entry = $DB->get_record('post', array('module'=>'blog', 'id'=>$entryid))) {
  86         send_file_not_found();
  87     }
  88
  89     if ('publishstate' === 'public') {
  90         if ($CFG->forcelogin) {
  91             require_login();
  92         }
  93
  94     } else if ('publishstate' === 'site') {
  95         require_login();
  96         //ok
  97     } else if ('publishstate' === 'draft') {
  98         require_login();
  99         if ($USER->id != $entry->userid) {
 100             send_file_not_found();
 101         }
 102     }
 103
 104     $filename = array_pop($args);
 105     $filepath = $args ? '/'.implode('/', $args).'/' : '/';
 106
 107     if (!$file = $fs->get_file($context->id, $component, $filearea, $entryid, $filepath, $filename) or $file->is_directory()) {
 108         send_file_not_found();
 109     }
 110
 111     send_stored_file($file, 10*60, 0, true); // download MUST be forced - security!
 112
 113 // ========================================================================================================================
 114 } else if ($component === 'grade') {
 115     if (($filearea === 'outcome' or $filearea === 'scale') and $context->contextlevel == CONTEXT_SYSTEM) {
 116         // Global gradebook files
 117         if ($CFG->forcelogin) {
 118             require_login();
 119         }
 120
 121         $fullpath = "/$context->id/$component/$filearea/".implode('/', $args);
 122
 123         if (!$file = $fs->get_file_by_hash(sha1($fullpath)) or $file->is_directory()) {
 124             send_file_not_found();
 125         }
 126
 127         session_get_instance()->write_close(); // unlock session during fileserving
 128         send_stored_file($file, 60*60, 0, $forcedownload);
 129
 130     } else if ($filearea === 'feedback' and $context->contextlevel == CONTEXT_COURSE) {
 131         //TODO: nobody implemented this yet in grade edit form!!
 132         send_file_not_found();
 133
 134         if ($CFG->forcelogin || $course->id != SITEID) {
 135             require_login($course);
 136         }
 137
 138         $fullpath = "/$context->id/$component/$filearea/".implode('/', $args);
 139
 140         if (!$file = $fs->get_file_by_hash(sha1($fullpath)) or $file->is_directory()) {
 141             send_file_not_found();
 142         }
 143
 144         session_get_instance()->write_close(); // unlock session during fileserving
 145         send_stored_file($file, 60*60, 0, $forcedownload);
 146     } else {
 147         send_file_not_found();
 148     }
 149
 150 // ========================================================================================================================
 151 } else if ($component === 'tag') {
 152     if ($filearea === 'description' and $context->contextlevel == CONTEXT_SYSTEM) {
 153
 154         // All tag descriptions are going to be public but we still need to respect forcelogin
 155         if ($CFG->forcelogin) {
 156             require_login();
 157         }
 158
 159         $fullpath = "/$context->id/tag/description/".implode('/', $args);
 160
 161         if (!$file = $fs->get_file_by_hash(sha1($fullpath)) or $file->is_directory()) {
 162             send_file_not_found();
 163         }
 164
 165         session_get_instance()->write_close(); // unlock session during fileserving
 166         send_stored_file($file, 60*60, 0, true);
 167
 168     } else {
 169         send_file_not_found();
 170     }
 171
 172 // ========================================================================================================================
 173 } else if ($component === 'calendar') {
 174     if ($filearea === 'event_description'  and $context->contextlevel == CONTEXT_SYSTEM) {
 175
 176         // All events here are public the one requirement is that we respect forcelogin
 177         if ($CFG->forcelogin) {
 178             require_login();
 179         }
 180
 181         // Get the event if from the args array
 182         $eventid = array_shift($args);
 183
 184         // Load the event from the database
 185         if (!$event = $DB->get_record('event', array('id'=>(int)$eventid, 'eventtype'=>'site'))) {
 186             send_file_not_found();
 187         }
 188         // Check that we got an event and that it's userid is that of the user
 189
 190         // Get the file and serve if successful
 191         $filename = array_pop($args);
 192         $filepath = $args ? '/'.implode('/', $args).'/' : '/';
 193         if (!$file = $fs->get_file($context->id, $component, $filearea, $eventid, $filepath, $filename) or $file->is_directory()) {
 194             send_file_not_found();
 195         }
 196
 197         session_get_instance()->write_close(); // unlock session during fileserving
 198         send_stored_file($file, 60*60, 0, $forcedownload);
 199
 200     } else if ($filearea === 'event_description' and $context->contextlevel == CONTEXT_USER) {
 201
 202         // Must be logged in, if they are not then they obviously can't be this user
 203         require_login();
 204
 205         // Don't want guests here, potentially saves a DB call
 206         if (isguestuser()) {
 207             send_file_not_found();
 208         }
 209
 210         // Get the event if from the args array
 211         $eventid = array_shift($args);
 212
 213         // Load the event from the database - user id must match
 214         if (!$event = $DB->get_record('event', array('id'=>(int)$eventid, 'userid'=>$USER->id, 'eventtype'=>'user'))) {
 215             send_file_not_found();
 216         }
 217
 218         // Get the file and serve if successful
 219         $filename = array_pop($args);
 220         $filepath = $args ? '/'.implode('/', $args).'/' : '/';
 221         if (!$file = $fs->get_file($context->id, $component, $filearea, $eventid, $filepath, $filename) or $file->is_directory()) {
 222             send_file_not_found();
 223         }
 224
 225         session_get_instance()->write_close(); // unlock session during fileserving
 226         send_stored_file($file, 60*60, 0, $forcedownload);
 227
 228     } else if ($filearea === 'event_description' and $context->contextlevel == CONTEXT_COURSE) {
 229
 230         // Respect forcelogin and require login unless this is the site.... it probably
 231         // should NEVER be the site
 232         if ($CFG->forcelogin || $course->id != SITEID) {
 233             require_login($course);
 234         }
 235
 236         // Must be able to at least view the course
 237         if (!is_enrolled($context) and !is_viewing($context)) {
 238             //TODO: hmm, do we really want to block guests here?
 239             send_file_not_found();
 240         }
 241
 242         // Get the event id
 243         $eventid = array_shift($args);
 244
 245         // Load the event from the database we need to check whether it is
 246         // a) valid course event
 247         // b) a group event
 248         // Group events use the course context (there is no group context)
 249         if (!$event = $DB->get_record('event', array('id'=>(int)$eventid, 'courseid'=>$course->id))) {
 250             send_file_not_found();
 251         }
 252
 253         // If its a group event require either membership of view all groups capability
 254         if ($event->eventtype === 'group') {
 255             if (!has_capability('moodle/site:accessallgroups', $context) && !groups_is_member($event->groupid, $USER->id)) {
 256                 send_file_not_found();
 257             }
 258         } else if ($event->eventtype === 'course') {
 259             //ok
 260         } else {
 261             // some other type
 262             send_file_not_found();
 263         }
 264
 265         // If we get this far we can serve the file
 266         $filename = array_pop($args);
 267         $filepath = $args ? '/'.implode('/', $args).'/' : '/';
 268         if (!$file = $fs->get_file($context->id, $component, $filearea, $eventid, $filepath, $filename) or $file->is_directory()) {
 269             send_file_not_found();
 270         }
 271
 272         session_get_instance()->write_close(); // unlock session during fileserving
 273         send_stored_file($file, 60*60, 0, $forcedownload);
 274
 275     } else {
 276         send_file_not_found();
 277     }
 278
 279 // ========================================================================================================================
 280 } else if ($component === 'user') {
 281     if ($filearea === 'icon' and $context->contextlevel == CONTEXT_USER) {
 282         $redirect = false;
 283         if (count($args) == 1) {
 284             $themename = theme_config::DEFAULT_THEME;
 285             $filename = array_shift($args);
 286         } else {
 287             $themename = array_shift($args);
 288             $filename = array_shift($args);
 289         }
 290         if ((!empty($CFG->forcelogin) and !isloggedin())) {
 291             // protect images if login required and not logged in;
 292             // do not use require_login() because it is expensive and not suitable here anyway
 293             $redirect = true;
 294         }
 295         if (!$redirect and ($filename !== 'f1' and $filename !== 'f2')) {
 296             $filename = 'f1';
 297             $redirect = true;
 298         }
 299         if (!$redirect && !$file = $fs->get_file($context->id, 'user', 'icon', 0, '/', $filename.'/.png')) {
 300             if (!$file = $fs->get_file($context->id, 'user', 'icon', 0, '/', $filename.'/.jpg')) {
 301                 $redirect = true;
 302             }
 303         }
 304         if ($redirect) {
 305             $theme = theme_config::load($themename);
 306             redirect($theme->pix_url('u/'.$filename, 'moodle'));
 307         }
 308         send_stored_file($file, 60*60*24); // enable long caching, there are many images on each page
 309
 310     } else if ($filearea === 'private' and $context->contextlevel == CONTEXT_USER) {
 311         require_login();
 312
 313         if (isguestuser()) {
 314             send_file_not_found();
 315         }
 316
 317         if ($USER->id !== $context->instanceid) {
 318             send_file_not_found();
 319         }
 320
 321         $filename = array_pop($args);
 322         $filepath = $args ? '/'.implode('/', $args).'/' : '/';
 323         if (!$file = $fs->get_file($context->id, $component, $filearea, 0, $filepath, $filename) or $file->is_directory()) {
 324             send_file_not_found();
 325         }
 326
 327         session_get_instance()->write_close(); // unlock session during fileserving
 328         send_stored_file($file, 0, 0, true); // must force download - security!
 329
 330     } else if ($filearea === 'profile' and $context->contextlevel == CONTEXT_USER) {
 331
 332         if ($CFG->forcelogin) {
 333             require_login();
 334         }
 335
 336         $userid = $context->instanceid;
 337
 338         if ($USER->id == $userid) {
 339             // always can access own
 340
 341         } else if (!empty($CFG->forceloginforprofiles)) {
 342             require_login();
 343
 344             if (isguestuser()) {
 345                 send_file_not_found();
 346             }
 347
 348             // we allow access to site profile of all course contacts (usually teachers)
 349             if (!has_coursecontact_role($userid) && !has_capability('moodle/user:viewdetails', $context)) {
 350                 send_file_not_found();
 351             }
 352
 353             $canview = false;
 354             if (has_capability('moodle/user:viewdetails', $context)) {
 355                 $canview = true;
 356             } else {
 357                 $courses = enrol_get_my_courses();
 358             }
 359
 360             while (!$canview && count($courses) > 0) {
 361                 $course = array_shift($courses);
 362                 if (has_capability('moodle/user:viewdetails', get_context_instance(CONTEXT_COURSE, $course->id))) {
 363                     $canview = true;
 364                 }
 365             }
 366         }
 367
 368         $filename = array_pop($args);
 369         $filepath = $args ? '/'.implode('/', $args).'/' : '/';
 370         if (!$file = $fs->get_file($context->id, $component, $filearea, 0, $filepath, $filename) or $file->is_directory()) {
 371             send_file_not_found();
 372         }
 373
 374         session_get_instance()->write_close(); // unlock session during fileserving
 375         send_stored_file($file, 0, 0, true); // must force download - security!
 376
 377     } else if ($filearea === 'profile' and $context->contextlevel == CONTEXT_COURSE) {
 378         $userid = (int)array_shift($args);
 379         $usercontext = get_context_instance(CONTEXT_USER, $userid);
 380
 381         if ($CFG->forcelogin) {
 382             require_login();
 383         }
 384
 385         if (!empty($CFG->forceloginforprofiles)) {
 386             require_login();
 387             if (isguestuser()) {
 388                 print_error('noguest');
 389             }
 390
 391             //TODO: review this logic of user profile access prevention
 392             if (!has_coursecontact_role($userid) and !has_capability('moodle/user:viewdetails', $usercontext)) {
 393                 print_error('usernotavailable');
 394             }
 395             if (!has_capability('moodle/user:viewdetails', $context) && !has_capability('moodle/user:viewdetails', $usercontext)) {
 396                 print_error('cannotviewprofile');
 397             }
 398             if (!is_enrolled($context, $userid)) {
 399                 print_error('notenrolledprofile');
 400             }
 401             if (groups_get_course_groupmode($course) == SEPARATEGROUPS and !has_capability('moodle/site:accessallgroups', $context)) {
 402                 print_error('groupnotamember');
 403             }
 404         }
 405
 406         $filename = array_pop($args);
 407         $filepath = $args ? '/'.implode('/', $args).'/' : '/';
 408         if (!$file = $fs->get_file($usercontext->id, 'user', 'profile', 0, $filepath, $filename) or $file->is_directory()) {
 409             send_file_not_found();
 410         }
 411
 412         session_get_instance()->write_close(); // unlock session during fileserving
 413         send_stored_file($file, 0, 0, true); // must force download - security!
 414
 415     } else if ($filearea === 'backup' and $context->contextlevel == CONTEXT_USER) {
 416         require_login();
 417
 418         if (isguestuser()) {
 419             send_file_not_found();
 420         }
 421         $userid = $context->instanceid;
 422
 423         if ($USER->id != $userid) {
 424             send_file_not_found();
 425         }
 426
 427         $filename = array_pop($args);
 428         $filepath = $args ? '/'.implode('/', $args).'/' : '/';
 429         if (!$file = $fs->get_file($context->id, 'user', 'backup', 0, $filepath, $filename) or $file->is_directory()) {
 430             send_file_not_found();
 431         }
 432
 433         session_get_instance()->write_close(); // unlock session during fileserving
 434         send_stored_file($file, 0, 0, true); // must force download - security!
 435
 436     } else {
 437         send_file_not_found();
 438     }
 439
 440 // ========================================================================================================================
 441 } else if ($component === 'coursecat') {
 442     if ($context->contextlevel != CONTEXT_COURSECAT) {
 443         send_file_not_found();
 444     }
 445
 446     if ($filearea === 'description') {
 447         if ($CFG->forcelogin) {
 448             // no login necessary - unless login forced everywhere
 449             require_login();
 450         }
 451
 452         $filename = array_pop($args);
 453         $filepath = $args ? '/'.implode('/', $args).'/' : '/';
 454         if (!$file = $fs->get_file($context->id, 'coursecat', 'description', 0, $filepath, $filename) or $file->is_directory()) {
 455             send_file_not_found();
 456         }
 457
 458         session_get_instance()->write_close(); // unlock session during fileserving
 459         send_stored_file($file, 60*60, 0, $forcedownload);
 460     } else {
 461         send_file_not_found();
 462     }
 463
 464 // ========================================================================================================================
 465 } else if ($component === 'course') {
 466     if ($context->contextlevel != CONTEXT_COURSE) {
 467         send_file_not_found();
 468     }
 469
 470     if ($filearea === 'summary') {
 471         if ($CFG->forcelogin) {
 472             require_login();
 473         }
 474
 475         $filename = array_pop($args);
 476         $filepath = $args ? '/'.implode('/', $args).'/' : '/';
 477         if (!$file = $fs->get_file($context->id, 'course', 'summary', 0, $filepath, $filename) or $file->is_directory()) {
 478             send_file_not_found();
 479         }
 480
 481         session_get_instance()->write_close(); // unlock session during fileserving
 482         send_stored_file($file, 60*60, 0, $forcedownload);
 483
 484     } else if ($filearea === 'section') {
 485         if ($CFG->forcelogin) {
 486             require_login($course);
 487         } else if ($course->id != SITEID) {
 488             require_login($course);
 489         }
 490
 491         $sectionid = (int)array_shift($args);
 492
 493         if (!$section = $DB->get_record('course_sections', array('id'=>$sectionid, 'course'=>$course->id))) {
 494             send_file_not_found();
 495         }
 496
 497         if ($course->numsections < $section->section) {
 498             if (!has_capability('moodle/course:update', $context)) {
 499                 // block access to unavailable sections if can not edit course
 500                 send_file_not_found();
 501             }
 502         }
 503
 504         $filename = array_pop($args);
 505         $filepath = $args ? '/'.implode('/', $args).'/' : '/';
 506         if (!$file = $fs->get_file($context->id, 'course', 'section', $sectionid, $filepath, $filename) or $file->is_directory()) {
 507             send_file_not_found();
 508         }
 509
 510         session_get_instance()->write_close(); // unlock session during fileserving
 511         send_stored_file($file, 60*60, 0, $forcedownload);
 512
 513     } else {
 514         send_file_not_found();
 515     }
 516
 517 } else if ($component === 'group') {
 518     if ($context->contextlevel != CONTEXT_COURSE) {
 519         send_file_not_found();
 520     }
 521
 522     require_course_login($course, true, null, false);
 523
 524     $groupid = (int)array_shift($args);
 525
 526     $group = $DB->get_record('groups', array('id'=>$groupid, 'courseid'=>$course->id), '*', MUST_EXIST);
 527     if (($course->groupmodeforce and $course->groupmode == SEPARATEGROUPS) and !has_capability('moodle/site:accessallgroups', $context) and !groups_is_member($group->id, $USER->id)) {
 528         // do not allow access to separate group info if not member or teacher
 529         send_file_not_found();
 530     }
 531
 532     if ($filearea === 'description') {
 533
 534         require_login($course);
 535
 536         $filename = array_pop($args);
 537         $filepath = $args ? '/'.implode('/', $args).'/' : '/';
 538         if (!$file = $fs->get_file($context->id, 'group', 'description', $group->id, $filepath, $filename) or $file->is_directory()) {
 539             send_file_not_found();
 540         }
 541
 542         session_get_instance()->write_close(); // unlock session during fileserving
 543         send_stored_file($file, 60*60, 0, $forcedownload);
 544
 545     } else if ($filearea === 'icon') {
 546         $filename = array_pop($args);
 547
 548         if ($filename !== 'f1' and $filename !== 'f2') {
 549             send_file_not_found();
 550         }
 551         if (!$file = $fs->get_file($context->id, 'group', 'icon', $group->id, '/', $filename.'.png')) {
 552             if (!$file = $fs->get_file($context->id, 'group', 'icon', $group->id, '/', $filename.'.jpg')) {
 553                 send_file_not_found();
 554             }
 555         }
 556
 557         session_get_instance()->write_close(); // unlock session during fileserving
 558         send_stored_file($file, 60*60);
 559
 560     } else {
 561         send_file_not_found();
 562     }
 563
 564 } else if ($component === 'grouping') {
 565     if ($context->contextlevel != CONTEXT_COURSE) {
 566         send_file_not_found();
 567     }
 568
 569     require_login($course);
 570
 571     $groupingid = (int)array_shift($args);
 572
 573     // note: everybody has access to grouping desc images for now
 574     if ($filearea === 'description') {
 575
 576         $filename = array_pop($args);
 577         $filepath = $args ? '/'.implode('/', $args).'/' : '/';
 578         if (!$file = $fs->get_file($context->id, 'grouping', 'description', $groupingid, $filepath, $filename) or $file->is_directory()) {
 579             send_file_not_found();
 580         }
 581
 582         session_get_instance()->write_close(); // unlock session during fileserving
 583         send_stored_file($file, 60*60, 0, $forcedownload);
 584
 585     } else {
 586         send_file_not_found();
 587     }
 588
 589 // ========================================================================================================================
 590 } else if ($component === 'backup') {
 591     if ($filearea === 'course' and $context->contextlevel == CONTEXT_COURSE) {
 592         require_login($course);
 593         require_capability('moodle/backup:downloadfile', $context);
 594
 595         $filename = array_pop($args);
 596         $filepath = $args ? '/'.implode('/', $args).'/' : '/';
 597         if (!$file = $fs->get_file($context->id, 'backup', 'course', 0, $filepath, $filename) or $file->is_directory()) {
 598             send_file_not_found();
 599         }
 600
 601         session_get_instance()->write_close(); // unlock session during fileserving
 602         send_stored_file($file, 0, 0, $forcedownload);
 603
 604     } else if ($filearea === 'section' and $context->contextlevel == CONTEXT_COURSE) {
 605         require_login($course);
 606         require_capability('moodle/backup:downloadfile', $context);
 607
 608         $sectionid = (int)array_shift($args);
 609
 610         $filename = array_pop($args);
 611         $filepath = $args ? '/'.implode('/', $args).'/' : '/';
 612         if (!$file = $fs->get_file($context->id, 'backup', 'section', $sectionid, $filepath, $filename) or $file->is_directory()) {
 613             send_file_not_found();
 614         }
 615
 616         session_get_instance()->write_close();
 617         send_stored_file($file, 60*60, 0, $forcedownload);
 618
 619     } else if ($filearea === 'activity' and $context->contextlevel == CONTEXT_MODULE) {
 620         require_login($course, false, $cm);
 621         require_capability('moodle/backup:downloadfile', $context);
 622
 623         $filename = array_pop($args);
 624         $filepath = $args ? '/'.implode('/', $args).'/' : '/';
 625         if (!$file = $fs->get_file($context->id, 'backup', 'activity', 0, $filepath, $filename) or $file->is_directory()) {
 626             send_file_not_found();
 627         }
 628
 629         session_get_instance()->write_close();
 630         send_stored_file($file, 60*60, 0, $forcedownload);
 631
 632     } else if ($filearea === 'automated' and $context->contextlevel == CONTEXT_COURSE) {
 633         // Backup files that were generated by the automated backup systems.
 634
 635         require_login($course);
 636         require_capability('moodle/site:config', $context);
 637
 638         $filename = array_pop($args);
 639         $filepath = $args ? '/'.implode('/', $args).'/' : '/';
 640         if (!$file = $fs->get_file($context->id, 'backup', 'automated', 0, $filepath, $filename) or $file->is_directory()) {
 641             send_file_not_found();
 642         }
 643
 644         session_get_instance()->write_close(); // unlock session during fileserving
 645         send_stored_file($file, 0, 0, $forcedownload);
 646
 647     } else {
 648         send_file_not_found();
 649     }
 650
 651 // ========================================================================================================================
 652 } else if ($component === 'question') {
 653     require_once($CFG->libdir . '/questionlib.php');
 654     question_pluginfile($course, $context, 'question', $filearea, $args, $forcedownload);
 655     send_file_not_found();
 656
 657 // ========================================================================================================================
 658 } else if ($component === 'grading') {
 659     if ($filearea === 'description') {
 660         // files embedded into the form definition description
 661
 662         if ($context->contextlevel == CONTEXT_SYSTEM) {
 663             require_login();
 664
 665         } else if ($context->contextlevel >= CONTEXT_COURSE) {
 666             require_login($course, false, $cm);
 667
 668         } else {
 669             send_file_not_found();
 670         }
 671
 672         $formid = (int)array_shift($args);
 673
 674         $sql = "SELECT ga.id
 675                   FROM {grading_areas} ga
 676                   JOIN {grading_definitions} gd ON (gd.areaid = ga.id)
 677                  WHERE gd.id = ? AND ga.contextid = ?";
 678         $areaid = $DB->get_field_sql($sql, array($formid, $context->id), IGNORE_MISSING);
 679
 680         if (!$areaid) {
 681             send_file_not_found();
 682         }
 683
 684         $fullpath = "/$context->id/$component/$filearea/$formid/".implode('/', $args);
 685
 686         if (!$file = $fs->get_file_by_hash(sha1($fullpath)) or $file->is_directory()) {
 687             send_file_not_found();
 688         }
 689
 690         session_get_instance()->write_close(); // unlock session during fileserving
 691         send_stored_file($file, 60*60, 0, $forcedownload);
 692     }
 693
 694 // ========================================================================================================================
 695 } else if (strpos($component, 'mod_') === 0) {
 696     $modname = substr($component, 4);
 697     if (!file_exists("$CFG->dirroot/mod/$modname/lib.php")) {
 698         send_file_not_found();
 699     }
 700     require_once("$CFG->dirroot/mod/$modname/lib.php");
 701
 702     if ($context->contextlevel == CONTEXT_MODULE) {
 703         if ($cm->modname !== $modname) {
 704             // somebody tries to gain illegal access, cm type must match the component!
 705             send_file_not_found();
 706         }
 707     }
 708
 709     if ($filearea === 'intro') {
 710         if (!plugin_supports('mod', $modname, FEATURE_MOD_INTRO, true)) {
 711             send_file_not_found();
 712         }
 713         require_course_login($course, true, $cm);
 714
 715         // all users may access it
 716         $filename = array_pop($args);
 717         $filepath = $args ? '/'.implode('/', $args).'/' : '/';
 718         if (!$file = $fs->get_file($context->id, 'mod_'.$modname, 'intro', 0, $filepath, $filename) or $file->is_directory()) {
 719             send_file_not_found();
 720         }
 721
 722         $lifetime = isset($CFG->filelifetime) ? $CFG->filelifetime : 86400;
 723
 724         // finally send the file
 725         send_stored_file($file, $lifetime, 0);
 726     }
 727
 728     $filefunction = $component.'_pluginfile';
 729     $filefunctionold = $modname.'_pluginfile';
 730     if (function_exists($filefunction)) {
 731         // if the function exists, it must send the file and terminate. Whatever it returns leads to "not found"
 732         $filefunction($course, $cm, $context, $filearea, $args, $forcedownload);
 733     } else if (function_exists($filefunctionold)) {
 734         // if the function exists, it must send the file and terminate. Whatever it returns leads to "not found"
 735         $filefunctionold($course, $cm, $context, $filearea, $args, $forcedownload);
 736     }
 737
 738     send_file_not_found();
 739
 740 // ========================================================================================================================
 741 } else if (strpos($component, 'block_') === 0) {
 742     $blockname = substr($component, 6);
 743     // note: no more class methods in blocks please, that is ....
 744     if (!file_exists("$CFG->dirroot/blocks/$blockname/lib.php")) {
 745         send_file_not_found();
 746     }
 747     require_once("$CFG->dirroot/blocks/$blockname/lib.php");
 748
 749     if ($context->contextlevel == CONTEXT_BLOCK) {
 750         $birecord = $DB->get_record('block_instances', array('id'=>$context->instanceid), '*',MUST_EXIST);
 751         if ($birecord->blockname !== $blockname) {
 752             // somebody tries to gain illegal access, cm type must match the component!
 753             send_file_not_found();
 754         }
 755     } else {
 756         $birecord = null;
 757     }
 758
 759     $filefunction = $component.'_pluginfile';
 760     if (function_exists($filefunction)) {
 761         // if the function exists, it must send the file and terminate. Whatever it returns leads to "not found"
 762         $filefunction($course, $birecord, $context, $filearea, $args, $forcedownload);
 763     }
 764
 765     send_file_not_found();
 766
 767 } else if (strpos($component, '_') === false) {
 768     // all core subsystems have to be specified above, no more guessing here!
 769     send_file_not_found();
 770
 771 } else {
 772     // try to serve general plugin file in arbitrary context
 773     $dir = get_component_directory($component);
 774     if (!file_exists("$dir/lib.php")) {
 775         send_file_not_found();
 776     }
 777     include_once("$dir/lib.php");
 778
 779     $filefunction = $component.'_pluginfile';
 780     if (function_exists($filefunction)) {
 781         // if the function exists, it must send the file and terminate. Whatever it returns leads to "not found"
 782         $filefunction($course, $cm, $context, $filearea, $args, $forcedownload);
 783     }
 784
 785     send_file_not_found();
 786 }