lib/componentlib.class.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 library includes all the necessary stuff to use the one-click
  20  * download and install feature of Moodle, used to keep updated some
  21  * items like languages, pear, enviroment... i.e, components.
  22  *
  23  * It has been developed harcoding some important limits that are
  24  * explained below:
  25  *    - It only can check, download and install items under moodledata.
  26  *    - Every downloadeable item must be one zip file.
  27  *    - The zip file root content must be 1 directory, i.e, everything
  28  *      is stored under 1 directory.
  29  *    - Zip file name and root directory must have the same name (but
  30  *      the .zip extension, of course).
  31  *    - Every .zip file must be defined in one .md5 file that will be
  32  *      stored in the same remote directory than the .zip file.
  33  *    - The name of such .md5 file is free, although it's recommended
  34  *      to use the same name than the .zip (that's the default
  35  *      assumption if no specified).
  36  *    - Every remote .md5 file will be a comma separated (CVS) file where each
  37  *      line will follow this format:
  38  *        - Field 1: name of the zip file (without extension). Mandatory.
  39  *        - Field 2: md5 of the zip file. Mandatory.
  40  *        - Field 3: whatever you want (or need). Optional.
  41  *    -Every local .md5 file will:
  42  *        - Have the zip file name (without the extension) plus -md5
  43  *        - Will reside inside the expanded zip file dir
  44  *        - Will contain the md5 od the latest installed component
  45  * With all these details present, the process will perform this tasks:
  46  *    - Perform security checks. Only admins are allowed to use this for now.
  47  *    - Read the .md5 file from source (1).
  48  *    - Extract the correct line for the .zip being requested.
  49  *    - Compare it with the local .md5 file (2).
  50  *    - If different:
  51  *        - Download the newer .zip file from source.
  52  *        - Calculate its md5 (3).
  53  *        - Compare (1) and (3).
  54  *        - If equal:
  55  *            - Delete old directory.
  56  *            - Uunzip the newer .zip file.
  57  *            - Create the new local .md5 file.
  58  *            - Delete the .zip file.
  59  *        - If different:
  60  *            - ERROR. Old package won't be modified. We shouldn't
  61  *              reach here ever.
  62  *    - If component download is not possible, a message text about how to do
  63  *      the process manually (remotedownloaderror) must be displayed to explain it.
  64  *
  65  * General Usage:
  66  *
  67  * To install one component:
  68  * <code>
  69  *     require_once($CFG->libdir.'/componentlib.class.php');
  70  *     if ($cd = new component_installer('https://download.moodle.org', 'langpack/2.0',
  71  *                                       'es.zip', 'languages.md5', 'lang')) {
  72  *         $status = $cd->install(); //returns COMPONENT_(ERROR | UPTODATE | INSTALLED)
  73  *         switch ($status) {
  74  *             case COMPONENT_ERROR:
  75  *                 if ($cd->get_error() == 'remotedownloaderror') {
  76  *                     $a = new stdClass();
  77  *                     $a->url = 'https://download.moodle.org/langpack/2.0/es.zip';
  78  *                     $a->dest= $CFG->dataroot.'/lang';
  79  *                     print_error($cd->get_error(), 'error', '', $a);
  80  *                 } else {
  81  *                     print_error($cd->get_error(), 'error');
  82  *                 }
  83  *                 break;
  84  *             case COMPONENT_UPTODATE:
  85  *                 //Print error string or whatever you want to do
  86  *                 break;
  87  *             case COMPONENT_INSTALLED:
  88  *                 //Print/do whatever you want
  89  *                 break;
  90  *             default:
  91  *                 //We shouldn't reach this point
  92  *         }
  93  *     } else {
  94  *         //We shouldn't reach this point
  95  *     }
  96  * </code>
  97  *
  98  * To switch of component (maintaining the rest of settings):
  99  * <code>
 100  *     $status = $cd->change_zip_file('en.zip'); //returns boolean false on error
 101  * </code>
 102  *
 103  * To retrieve all the components in one remote md5 file
 104  * <code>
 105  *     $components = $cd->get_all_components_md5();  //returns boolean false on error, array instead
 106  * </code>
 107  *
 108  * To check if current component needs to be updated
 109  * <code>
 110  *     $status = $cd->need_upgrade();  //returns COMPONENT_(ERROR | UPTODATE | NEEDUPDATE)
 111  * </code>
 112  *
 113  * To get the 3rd field of the md5 file (optional)
 114  * <code>
 115  *     $field = $cd->get_extra_md5_field();  //returns string (empty if not exists)
 116  * </code>
 117  *
 118  * For all the error situations the $cd->get_error() method should return always the key of the
 119  * error to be retrieved by one standard get_string() call against the error.php lang file.
 120  *
 121  * That's all!
 122  *
 123  * @package   core
 124  * @copyright (C) 2001-3001 Eloy Lafuente (stronk7) {@link http://contiento.com}
 125  * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
 126  */
 127
 128 defined('MOODLE_INTERNAL') || die();
 129
 130  /**
 131   * @global object $CFG
 132   * @name $CFG
 133   */
 134 global $CFG;
 135 require_once($CFG->libdir.'/filelib.php');
 136
 137 // Some needed constants
 138 define('COMPONENT_ERROR',           0);
 139 define('COMPONENT_UPTODATE',        1);
 140 define('COMPONENT_NEEDUPDATE',      2);
 141 define('COMPONENT_INSTALLED',       3);
 142
 143 /**
 144  * This class is used to check, download and install items from
 145  * download.moodle.org to the moodledata directory.
 146  *
 147  * It always return true/false in all their public methods to say if
 148  * execution has ended succesfuly or not. If there is any problem
 149  * its getError() method can be called, returning one error string
 150  * to be used with the standard get/print_string() functions.
 151  *
 152  * @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
 153  * @package moodlecore
 154  */
 155 class component_installer {
 156     /**
 157      * @var string
 158      */
 159     var $sourcebase;   /// Full http URL, base for downloadable items
 160     var $zippath;      /// Relative path (from sourcebase) where the
 161                        /// downloadeable item resides.
 162     var $zipfilename;  /// Name of the .zip file to be downloaded
 163     var $md5filename;  /// Name of the .md5 file to be read
 164     var $componentname;/// Name of the component. Must be the zip name without
 165                        /// the extension. And it defines a lot of things:
 166                        /// the md5 line to search for, the default m5 file name
 167                        /// and the name of the root dir stored inside the zip file
 168     var $destpath;     /// Relative path (from moodledata) where the .zip
 169                        /// file will be expanded.
 170     var $errorstring;  /// Latest error produced. It will contain one lang string key.
 171     var $extramd5info; /// Contents of the optional third field in the .md5 file.
 172     var $requisitesok; /// Flag to see if requisites check has been passed ok.
 173     /**
 174      * @var array
 175      */
 176     var $cachedmd5components; /// Array of cached components to avoid to
 177                               /// download the same md5 file more than once per request.
 178
 179     /**
 180      * Standard constructor of the class. It will initialize all attributes.
 181      * without performing any check at all.
 182      *
 183      * @param string $sourcebase Full http URL, base for downloadeable items
 184      * @param string $zippath Relative path (from sourcebase) where the
 185      *               downloadeable item resides
 186      * @param string $zipfilename Name of the .zip file to be downloaded
 187      * @param string $md5filename Name of the .md5 file to be read (default '' = same
 188      *               than zipfilename)
 189      * @param string $destpath Relative path (from moodledata) where the .zip file will
 190      *               be expanded (default='' = moodledataitself)
 191      * @return object
 192      */
 193     function component_installer ($sourcebase, $zippath, $zipfilename, $md5filename='', $destpath='') {
 194
 195         $this->sourcebase   = $sourcebase;
 196         $this->zippath      = $zippath;
 197         $this->zipfilename  = $zipfilename;
 198         $this->md5filename  = $md5filename;
 199         $this->componentname= '';
 200         $this->destpath     = $destpath;
 201         $this->errorstring  = '';
 202         $this->extramd5info = '';
 203         $this->requisitesok = false;
 204         $this->cachedmd5components = array();
 205
 206         $this->check_requisites();
 207     }
 208
 209     /**
 210      * This function will check if everything is properly set to begin
 211      * one installation. Also, it will check for required settings
 212      * and will fill everything as needed.
 213      *
 214      * @global object
 215      * @return boolean true/false (plus detailed error in errorstring)
 216      */
 217     function check_requisites() {
 218         global $CFG;
 219
 220         $this->requisitesok = false;
 221
 222     /// Check that everything we need is present
 223         if (empty($this->sourcebase) || empty($this->zipfilename)) {
 224             $this->errorstring='missingrequiredfield';
 225             return false;
 226         }
 227     /// Check for correct sourcebase (this will be out in the future)
 228         if (!PHPUNIT_TEST and $this->sourcebase != 'https://download.moodle.org') {
 229             $this->errorstring='wrongsourcebase';
 230             return false;
 231         }
 232     /// Check the zip file is a correct one (by extension)
 233         if (stripos($this->zipfilename, '.zip') === false) {
 234             $this->errorstring='wrongzipfilename';
 235             return false;
 236         }
 237     /// Check that exists under dataroot
 238         if (!empty($this->destpath)) {
 239             if (!file_exists($CFG->dataroot.'/'.$this->destpath)) {
 240                 $this->errorstring='wrongdestpath';
 241                 return false;
 242             }
 243         }
 244     /// Calculate the componentname
 245         $pos = stripos($this->zipfilename, '.zip');
 246         $this->componentname = substr($this->zipfilename, 0, $pos);
 247     /// Calculate md5filename if it's empty
 248         if (empty($this->md5filename)) {
 249             $this->md5filename = $this->componentname.'.md5';
 250         }
 251     /// Set the requisites passed flag
 252         $this->requisitesok = true;
 253         return true;
 254     }
 255
 256     /**
 257      * This function will perform the full installation if needed, i.e.
 258      * compare md5 values, download, unzip, install and regenerate
 259      * local md5 file
 260      *
 261      * @global object
 262      * @uses COMPONENT_ERROR
 263      * @uses COMPONENT_UPTODATE
 264      * @uses COMPONENT_ERROR
 265      * @uses COMPONENT_INSTALLED
 266      * @return int COMPONENT_(ERROR | UPTODATE | INSTALLED)
 267      */
 268     function install() {
 269
 270         global $CFG;
 271
 272     /// Check requisites are passed
 273         if (!$this->requisitesok) {
 274             return COMPONENT_ERROR;
 275         }
 276     /// Confirm we need upgrade
 277         if ($this->need_upgrade() === COMPONENT_ERROR) {
 278             return COMPONENT_ERROR;
 279         } else if ($this->need_upgrade() === COMPONENT_UPTODATE) {
 280             $this->errorstring='componentisuptodate';
 281             return COMPONENT_UPTODATE;
 282         }
 283     /// Create temp directory if necesary
 284         if (!make_temp_directory('', false)) {
 285              $this->errorstring='cannotcreatetempdir';
 286              return COMPONENT_ERROR;
 287         }
 288     /// Download zip file and save it to temp
 289         if ($this->zippath) {
 290             $source = $this->sourcebase.'/'.$this->zippath.'/'.$this->zipfilename;
 291         } else {
 292             $source = $this->sourcebase.'/'.$this->zipfilename;
 293         }
 294
 295         $zipfile= $CFG->tempdir.'/'.$this->zipfilename;
 296
 297         if($contents = download_file_content($source)) {
 298             if ($file = fopen($zipfile, 'w')) {
 299                 if (!fwrite($file, $contents)) {
 300                     fclose($file);
 301                     $this->errorstring='cannotsavezipfile';
 302                     return COMPONENT_ERROR;
 303                 }
 304             } else {
 305                 $this->errorstring='cannotsavezipfile';
 306                 return COMPONENT_ERROR;
 307             }
 308             fclose($file);
 309         } else {
 310             $this->errorstring='cannotdownloadzipfile';
 311             return COMPONENT_ERROR;
 312         }
 313     /// Calculate its md5
 314         $new_md5 = md5($contents);
 315     /// Compare it with the remote md5 to check if we have the correct zip file
 316         if (!$remote_md5 = $this->get_component_md5()) {
 317             return COMPONENT_ERROR;
 318         }
 319         if ($new_md5 != $remote_md5) {
 320             $this->errorstring='downloadedfilecheckfailed';
 321             return COMPONENT_ERROR;
 322         }
 323     /// Move current revision to a safe place
 324         $destinationdir = $CFG->dataroot.'/'.$this->destpath;
 325         $destinationcomponent = $destinationdir.'/'.$this->componentname;
 326         @remove_dir($destinationcomponent.'_old');     // Deleting a possible old version.
 327
 328         // Moving to a safe place.
 329         @rename($destinationcomponent, $destinationcomponent.'_old');
 330
 331     /// Unzip new version
 332         if (!unzip_file($zipfile, $destinationdir, false)) {
 333         /// Error so, go back to the older
 334             @remove_dir($destinationcomponent);
 335             @rename ($destinationcomponent.'_old', $destinationcomponent);
 336             $this->errorstring='cannotunzipfile';
 337             return COMPONENT_ERROR;
 338         }
 339     /// Delete old component version
 340         @remove_dir($destinationcomponent.'_old');
 341     /// Create local md5
 342         if ($file = fopen($destinationcomponent.'/'.$this->componentname.'.md5', 'w')) {
 343             if (!fwrite($file, $new_md5)) {
 344                 fclose($file);
 345                 $this->errorstring='cannotsavemd5file';
 346                 return COMPONENT_ERROR;
 347             }
 348         } else  {
 349             $this->errorstring='cannotsavemd5file';
 350             return COMPONENT_ERROR;
 351         }
 352         fclose($file);
 353     /// Delete temp zip file
 354         @unlink($zipfile);
 355
 356         return COMPONENT_INSTALLED;
 357     }
 358
 359     /**
 360      * This function will detect if remote component needs to be installed
 361      * because it's different from the local one
 362      *
 363      * @uses COMPONENT_ERROR
 364      * @uses COMPONENT_UPTODATE
 365      * @uses COMPONENT_NEEDUPDATE
 366      * @return int COMPONENT_(ERROR | UPTODATE | NEEDUPDATE)
 367      */
 368     function need_upgrade() {
 369
 370     /// Check requisites are passed
 371         if (!$this->requisitesok) {
 372             return COMPONENT_ERROR;
 373         }
 374     /// Get local md5
 375         $local_md5 = $this->get_local_md5();
 376     /// Get remote md5
 377         if (!$remote_md5 = $this->get_component_md5()) {
 378             return COMPONENT_ERROR;
 379         }
 380     /// Return result
 381        if ($local_md5 == $remote_md5) {
 382            return COMPONENT_UPTODATE;
 383        } else {
 384            return COMPONENT_NEEDUPDATE;
 385        }
 386     }
 387
 388     /**
 389      * This function will change the zip file to install on the fly
 390      * to allow the class to process different components of the
 391      * same md5 file without intantiating more objects.
 392      *
 393      * @param string $newzipfilename New zip filename to process
 394      * @return boolean true/false
 395      */
 396     function change_zip_file($newzipfilename) {
 397
 398         $this->zipfilename = $newzipfilename;
 399         return $this->check_requisites();
 400     }
 401
 402     /**
 403      * This function will get the local md5 value of the installed
 404      * component.
 405      *
 406      * @global object
 407      * @return bool|string md5 of the local component (false on error)
 408      */
 409     function get_local_md5() {
 410         global $CFG;
 411
 412     /// Check requisites are passed
 413         if (!$this->requisitesok) {
 414             return false;
 415         }
 416
 417         $return_value = 'needtobeinstalled';   /// Fake value to force new installation
 418
 419     /// Calculate source to read
 420        $source = $CFG->dataroot.'/'.$this->destpath.'/'.$this->componentname.'/'.$this->componentname.'.md5';
 421     /// Read md5 value stored (if exists)
 422        if (file_exists($source)) {
 423            if ($temp = file_get_contents($source)) {
 424                $return_value = $temp;
 425            }
 426         }
 427         return $return_value;
 428     }
 429
 430     /**
 431      * This function will download the specified md5 file, looking for the
 432      * current componentname, returning its md5 field and storing extramd5info
 433      * if present. Also it caches results to cachedmd5components for better
 434      * performance in the same request.
 435      *
 436      * @return mixed md5 present in server (or false if error)
 437      */
 438     function get_component_md5() {
 439
 440     /// Check requisites are passed
 441         if (!$this->requisitesok) {
 442             return false;
 443         }
 444     /// Get all components of md5 file
 445         if (!$comp_arr = $this->get_all_components_md5()) {
 446             if (empty($this->errorstring)) {
 447                 $this->errorstring='cannotdownloadcomponents';
 448             }
 449             return false;
 450         }
 451     /// Search for the componentname component
 452         if (empty($comp_arr[$this->componentname]) || !$component = $comp_arr[$this->componentname]) {
 453              $this->errorstring='cannotfindcomponent';
 454              return false;
 455         }
 456     /// Check we have a valid md5
 457         if (empty($component[1]) || strlen($component[1]) != 32) {
 458             $this->errorstring='invalidmd5';
 459             return false;
 460         }
 461     /// Set the extramd5info field
 462         if (!empty($component[2])) {
 463             $this->extramd5info = $component[2];
 464         }
 465         return $component[1];
 466     }
 467
 468     /**
 469      * This function allows you to retrieve the complete array of components found in
 470      * the md5filename
 471      *
 472      * @return bool|array array of components in md5 file or false if error
 473      */
 474     function get_all_components_md5() {
 475
 476     /// Check requisites are passed
 477         if (!$this->requisitesok) {
 478             return false;
 479         }
 480
 481     /// Initialize components array
 482         $comp_arr = array();
 483
 484     /// Define and retrieve the full md5 file
 485         if ($this->zippath) {
 486             $source = $this->sourcebase.'/'.$this->zippath.'/'.$this->md5filename;
 487         } else {
 488             $source = $this->sourcebase.'/'.$this->md5filename;
 489         }
 490
 491     /// Check if we have downloaded the md5 file before (per request cache)
 492         if (!empty($this->cachedmd5components[$source])) {
 493             $comp_arr = $this->cachedmd5components[$source];
 494         } else {
 495         /// Not downloaded, let's do it now
 496             $availablecomponents = array();
 497
 498             if ($contents = download_file_content($source)) {
 499             /// Split text into lines
 500                 $lines=preg_split('/\r?\n/',$contents);
 501             /// Each line will be one component
 502                 foreach($lines as $line) {
 503                     $availablecomponents[] = explode(',', $line);
 504                 }
 505             /// If no components have been found, return error
 506                 if (empty($availablecomponents)) {
 507                     $this->errorstring='cannotdownloadcomponents';
 508                     return false;
 509                 }
 510             /// Build an associative array of components for easily search
 511             /// applying trim to avoid linefeeds and other...
 512                 $comp_arr = array();
 513                 foreach ($availablecomponents as $component) {
 514                 /// Avoid sometimes empty lines
 515                     if (empty($component[0])) {
 516                         continue;
 517                     }
 518                     $component[0]=trim($component[0]);
 519                     if (!empty($component[1])) {
 520                         $component[1]=trim($component[1]);
 521                     }
 522                     if (!empty($component[2])) {
 523                         $component[2]=trim($component[2]);
 524                     }
 525                     $comp_arr[$component[0]] = $component;
 526                 }
 527             /// Cache components
 528                 $this->cachedmd5components[$source] = $comp_arr;
 529             } else {
 530             /// Return error
 531                 $this->errorstring='remotedownloaderror';
 532                 return false;
 533             }
 534         }
 535     /// If there is no commponents or erros found, error
 536         if (!empty($this->errorstring)) {
 537              return false;
 538
 539         } else if (empty($comp_arr)) {
 540              $this->errorstring='cannotdownloadcomponents';
 541              return false;
 542         }
 543         return $comp_arr;
 544     }
 545
 546     /**
 547      * This function returns the errorstring
 548      *
 549      * @return string the error string
 550      */
 551     function get_error() {
 552         return $this->errorstring;
 553     }
 554
 555     /** This function returns the extramd5 field (optional in md5 file)
 556      *
 557      * @return string the extramd5 field
 558      */
 559     function get_extra_md5_field() {
 560         return $this->extramd5info;
 561     }
 562
 563 } /// End of component_installer class
 564
 565
 566 /**
 567  * Language packs installer
 568  *
 569  * This class wraps the functionality provided by {@link component_installer}
 570  * and adds support for installing a set of language packs.
 571  *
 572  * Given an array of required language packs, this class fetches them all
 573  * and installs them. It detects eventual dependencies and installs
 574  * all parent languages, too.
 575  *
 576  * @copyright 2011 David Mudrak <david@moodle.com>
 577  * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
 578  */
 579 class lang_installer {
 580
 581     /** lang pack was successfully downloaded and deployed */
 582     const RESULT_INSTALLED      = 'installed';
 583     /** lang pack was up-to-date so no download was needed */
 584     const RESULT_UPTODATE       = 'uptodate';
 585     /** there was a problem with downloading the lang pack */
 586     const RESULT_DOWNLOADERROR  = 'downloaderror';
 587
 588     /** @var array of languages to install */
 589     protected $queue = array();
 590     /** @var string the code of language being currently installed */
 591     protected $current;
 592     /** @var array of languages already installed by this instance */
 593     protected $done = array();
 594     /** @var string this Moodle major version */
 595     protected $version;
 596
 597     /**
 598      * Prepare the installer
 599      *
 600      * @param string|array $langcode a code of the language to install
 601      */
 602     public function __construct($langcode = '') {
 603         global $CFG;
 604
 605         $this->set_queue($langcode);
 606         $this->version = moodle_major_version(true);
 607
 608         if (!empty($CFG->langotherroot) and $CFG->langotherroot !== $CFG->dataroot . '/lang') {
 609             debugging('The in-built language pack installer does not support alternative location ' .
 610                 'of languages root directory. You are supposed to install and update your language '.
 611                 'packs on your own.');
 612         }
 613     }
 614
 615     /**
 616      * Sets the queue of language packs to be installed
 617      *
 618      * @param string|array $langcodes language code like 'cs' or a list of them
 619      */
 620     public function set_queue($langcodes) {
 621         if (is_array($langcodes)) {
 622             $this->queue = $langcodes;
 623         } else if (!empty($langcodes)) {
 624             $this->queue = array($langcodes);
 625         }
 626     }
 627
 628     /**
 629      * Runs the installer
 630      *
 631      * This method calls {@link self::install_language_pack} for every language in the
 632      * queue. If a dependency is detected, the parent language is added to the queue.
 633      *
 634      * @return array results, array of self::RESULT_xxx constants indexed by language code
 635      */
 636     public function run() {
 637
 638         $results = array();
 639
 640         while ($this->current = array_shift($this->queue)) {
 641
 642             if ($this->was_processed($this->current)) {
 643                 // do not repeat yourself
 644                 continue;
 645             }
 646
 647             if ($this->current === 'en') {
 648                 $this->mark_processed($this->current);
 649                 continue;
 650             }
 651
 652             $results[$this->current] = $this->install_language_pack($this->current);
 653
 654             if (in_array($results[$this->current], array(self::RESULT_INSTALLED, self::RESULT_UPTODATE))) {
 655                 if ($parentlang = $this->get_parent_language($this->current)) {
 656                     if (!$this->is_queued($parentlang) and !$this->was_processed($parentlang)) {
 657                         $this->add_to_queue($parentlang);
 658                     }
 659                 }
 660             }
 661
 662             $this->mark_processed($this->current);
 663         }
 664
 665         return $results;
 666     }
 667
 668     /**
 669      * Returns the URL where a given language pack can be downloaded
 670      *
 671      * Alternatively, if the parameter is empty, returns URL of the page with the
 672      * list of all available language packs.
 673      *
 674      * @param string $langcode language code like 'cs' or empty for unknown
 675      * @return string URL
 676      */
 677     public function lang_pack_url($langcode = '') {
 678
 679         if (empty($langcode)) {
 680             return 'https://download.moodle.org/langpack/'.$this->version.'/';
 681         } else {
 682             return 'https://download.moodle.org/download.php/langpack/'.$this->version.'/'.$langcode.'.zip';
 683         }
 684     }
 685
 686     /**
 687      * Returns the list of available language packs from download.moodle.org
 688      *
 689      * @return array|bool false if can not download
 690      */
 691     public function get_remote_list_of_languages() {
 692         $source = 'https://download.moodle.org/langpack/' . $this->version . '/languages.md5';
 693         $availablelangs = array();
 694
 695         if ($content = download_file_content($source)) {
 696             $alllines = explode("\n", $content);
 697             foreach($alllines as $line) {
 698                 if (!empty($line)){
 699                     $availablelangs[] = explode(',', $line);
 700                 }
 701             }
 702             return $availablelangs;
 703
 704         } else {
 705             return false;
 706         }
 707     }
 708
 709     // Internal implementation /////////////////////////////////////////////////
 710
 711     /**
 712      * Adds a language pack (or a list of them) to the queue
 713      *
 714      * @param string|array $langcodes code of the language to install or a list of them
 715      */
 716     protected function add_to_queue($langcodes) {
 717         if (is_array($langcodes)) {
 718             $this->queue = array_merge($this->queue, $langcodes);
 719         } else if (!empty($langcodes)) {
 720             $this->queue[] = $langcodes;
 721         }
 722     }
 723
 724     /**
 725      * Checks if the given language is queued or if the queue is empty
 726      *
 727      * @example $installer->is_queued('es');    // is Spanish going to be installed?
 728      * @example $installer->is_queued();        // is there a language queued?
 729      *
 730      * @param string $langcode language code or empty string for "any"
 731      * @return boolean
 732      */
 733     protected function is_queued($langcode = '') {
 734
 735         if (empty($langcode)) {
 736             return !empty($this->queue);
 737
 738         } else {
 739             return in_array($langcode, $this->queue);
 740         }
 741     }
 742
 743     /**
 744      * Checks if the given language has already been processed by this instance
 745      *
 746      * @see self::mark_processed()
 747      * @param string $langcode
 748      * @return boolean
 749      */
 750     protected function was_processed($langcode) {
 751         return isset($this->done[$langcode]);
 752     }
 753
 754     /**
 755      * Mark the given language pack as processed
 756      *
 757      * @see self::was_processed()
 758      * @param string $langcode
 759      */
 760     protected function mark_processed($langcode) {
 761         $this->done[$langcode] = 1;
 762     }
 763
 764     /**
 765      * Returns a parent language of the given installed language
 766      *
 767      * @param string $langcode
 768      * @return string parent language's code
 769      */
 770     protected function get_parent_language($langcode) {
 771         return get_parent_language($langcode);
 772     }
 773
 774     /**
 775      * Perform the actual language pack installation
 776      *
 777      * @uses component_installer
 778      * @param string $langcode
 779      * @return int return status
 780      */
 781     protected function install_language_pack($langcode) {
 782
 783         // initialise new component installer to process this language
 784         $installer = new component_installer('https://download.moodle.org', 'download.php/direct/langpack/' . $this->version,
 785             $langcode . '.zip', 'languages.md5', 'lang');
 786
 787         if (!$installer->requisitesok) {
 788             throw new lang_installer_exception('installer_requisites_check_failed');
 789         }
 790
 791         $status = $installer->install();
 792
 793         if ($status == COMPONENT_ERROR) {
 794             if ($installer->get_error() === 'remotedownloaderror') {
 795                 return self::RESULT_DOWNLOADERROR;
 796             } else {
 797                 throw new lang_installer_exception($installer->get_error(), $langcode);
 798             }
 799
 800         } else if ($status == COMPONENT_UPTODATE) {
 801             return self::RESULT_UPTODATE;
 802
 803         } else if ($status == COMPONENT_INSTALLED) {
 804             return self::RESULT_INSTALLED;
 805
 806         } else {
 807             throw new lang_installer_exception('unexpected_installer_result', $status);
 808         }
 809     }
 810 }
 811
 812
 813 /**
 814  * Exception thrown by {@link lang_installer}
 815  *
 816  * @copyright 2011 David Mudrak <david@moodle.com>
 817  * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
 818  */
 819 class lang_installer_exception extends moodle_exception {
 820
 821     public function __construct($errorcode, $debuginfo = null) {
 822         parent::__construct($errorcode, 'error', '', null, $debuginfo);
 823     }
 824 }