Proyectos de Subversion Moodle

<?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/>.

/**

 * This plugin is used to access equella repositories.

 *

 * @since Moodle 2.3

 * @package    repository_equella

 * @copyright  2012 Dongsheng Cai {@link http://dongsheng.org}

 * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later

 */

defined('MOODLE_INTERNAL') || die();

require_once($CFG->dirroot . '/repository/lib.php');

/**

 * repository_equella class implements equella_client

 *

 * @since Moodle 2.3

 * @package    repository_equella

 * @copyright  2012 Dongsheng Cai {@link http://dongsheng.org}

 * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later

 */

class repository_equella extends repository {

    /** @var array mimetype filter */

    private $mimetypes = array();

    /**

     * Constructor

     *

     * @param int $repositoryid repository instance id

     * @param int|stdClass $context a context id or context object

     * @param array $options repository options

     */

    public function __construct($repositoryid, $context = SYSCONTEXTID, $options = array()) {

        parent::__construct($repositoryid, $context, $options);

        if (isset($this->options['mimetypes'])) {

            $mt = $this->options['mimetypes'];

            if (!empty($mt) && is_array($mt) && !in_array('*', $mt)) {

                $this->mimetypes = array_unique(array_map(array($this, 'to_mime_type'), $mt));

            }

        }

    }

    /**

     * Display embedded equella interface

     *

     * @param string $path

     * @param mixed $page

     * @return array

     */

    public function get_listing($path = null, $page = null) {

        global $COURSE;

        $callbackurl = new moodle_url('/repository/equella/callback.php', array('repo_id'=>$this->id));

        $mimetypesstr = '';

        $restrict = '';

        if (!empty($this->mimetypes)) {

            $mimetypesstr = '&mimeTypes=' . implode(',', $this->mimetypes);

            // We're restricting to a mime type, so we always restrict to selecting resources only.

            $restrict = '&attachmentonly=true';

        } else if ($this->get_option('equella_select_restriction') != 'none') {

            // The option value matches the EQUELLA paramter name.

            $restrict = '&' . $this->get_option('equella_select_restriction') . '=true';

        }

        $url = $this->get_option('equella_url')

                . '?method=lms'

                . '&returnurl='.urlencode($callbackurl)

                . '&returnprefix=tle'

                . '&template=standard'

                . '&token='.urlencode($this->getssotoken('write'))

                . '&courseId='.urlencode($COURSE->idnumber)

                . '&courseCode='.urlencode($COURSE->shortname)

                . '&action=searchThin'

                . '&forcePost=true'

                . '&cancelDisabled=true'

                . '&attachmentUuidUrls=true'

                . '&options='.urlencode($this->get_option('equella_options') . $mimetypesstr)

                . $restrict;

        $manageurl = $this->get_option('equella_url');

        $manageurl = str_ireplace('signon.do', 'logon.do', $manageurl);

        $manageurl = $this->appendtoken($manageurl);

        $list = array();

        $list['object'] = array();

        $list['object']['type'] = 'text/html';

        $list['object']['src'] = $url;

        $list['nologin']  = true;

        $list['nosearch'] = true;

        $list['norefresh'] = true;

        $list['manage'] = $manageurl;

        return $list;

    }

    /**

     * Supported equella file types

     *

     * @return int

     */

    public function supported_returntypes() {

        return (FILE_INTERNAL | FILE_REFERENCE);

    }

    /**

     * Prepare file reference information

     *

     * @param string $source

     * @return string file referece

     */

    public function get_file_reference($source) {

        // Internally we store serialized value but user input is json-encoded for security reasons.

        $ref = json_decode(base64_decode($source));

        $filename  = clean_param($ref->filename, PARAM_FILE);

        $url = clean_param($ref->url, PARAM_URL);

        return base64_encode(serialize((object)array('url' => $url, 'filename' => $filename)));

    }

    /**

     * Counts the number of failed connections.

     *

     * If we received the connection timeout more than 3 times in a row, we don't attemt to

     * connect to the server any more during this request.

     *

     * This function is used by {@link repository_equella::sync_reference()} that

     * synchronises the file size of referenced files.

     *

     * @param int $errno omit if we just want to know the return value, the last curl_errno otherwise

     * @return bool true if we had less than 3 failed connections, false if no more connections

     * attempts recommended

     */

    private function connection_result($errno = null) {

        static $countfailures = array();

        $sess = sesskey();

        if (!array_key_exists($sess, $countfailures)) {

            $countfailures[$sess] = 0;

        }

        if ($errno !== null) {

            if ($errno == 0) {

                // reset count of failed connections

                $countfailures[$sess] = 0;

            } else if ($errno == 7 /*CURLE_COULDNT_CONNECT*/ || $errno == 9 /*CURLE_REMOTE_ACCESS_DENIED*/) {

                // problems with server

                $countfailures[$sess]++;

            }

        }

        return ($countfailures[$sess] < 3);

    }

    /**

     * Returned unserialized object from base64 encoded file reference data

     *

     * @param string $reference

     * @return stdClass

     */

    private function unserialize_reference(string $reference): stdClass {

        $decoded = base64_decode($reference);

        return unserialize_object($decoded);

    }

    /**

     * Download a file, this function can be overridden by subclass. {@link curl}

     *

     * @param string $reference the source of the file

     * @param string $filename filename (without path) to save the downloaded file in the

     * temporary directory

     * @return null|array null if download failed or array with elements:

     *   path: internal location of the file

     *   url: URL to the source (from parameters)

     */

    public function get_file($reference, $filename = '') {

        global $USER, $CFG;

        $ref = $this->unserialize_reference($reference);

        if (!isset($ref->url) || !($url = $this->appendtoken($ref->url))) {

            // Occurs when the user isn't known..

            return null;

        }

        $path = $this->prepare_file($filename);

        $cookiepathname = $this->prepare_file($USER->id. '_'. uniqid('', true). '.cookie');

        $c = new curl(array('cookie'=>$cookiepathname));

        $result = $c->download_one($url, null, array('filepath' => $path, 'followlocation' => true, 'timeout' => $CFG->repositorygetfiletimeout));

        // Delete cookie jar.

        if (file_exists($cookiepathname)) {

            unlink($cookiepathname);

        }

        if ($result !== true) {

            throw new moodle_exception('errorwhiledownload', 'repository', '', $result);

        }

        return array('path'=>$path, 'url'=>$url);

    }

    public function sync_reference(stored_file $file) {

        global $USER, $CFG;

        if ($file->get_referencelastsync() + DAYSECS > time() || !$this->connection_result()) {

            // Synchronise not more often than once a day.

            // if we had several unsuccessfull attempts to connect to server - do not try any more.

            return false;

        }

        $ref = $this->unserialize_reference($file->get_reference());

        if (!isset($ref->url) || !($url = $this->appendtoken($ref->url))) {

            // Occurs when the user isn't known..

            $file->set_missingsource();

            return true;

        }

        $cookiepathname = $this->prepare_file($USER->id. '_'. uniqid('', true). '.cookie');

        $c = new curl(array('cookie' => $cookiepathname));

        if (file_extension_in_typegroup($ref->filename, 'web_image')) {

            $path = $this->prepare_file('');

            $result = $c->download_one($url, null, array('filepath' => $path, 'followlocation' => true, 'timeout' => $CFG->repositorysyncimagetimeout));

            if ($result === true) {

                $file->set_synchronised_content_from_file($path);

                return true;

            }

        } else {

            $result = $c->head($url, array('followlocation' => true, 'timeout' => $CFG->repositorysyncfiletimeout));

        }

        // Delete cookie jar.

        if (file_exists($cookiepathname)) {

            unlink($cookiepathname);

        }

        $this->connection_result($c->get_errno());

        $curlinfo = $c->get_info();

        if (isset($curlinfo['http_code']) && $curlinfo['http_code'] == 200

                && array_key_exists('download_content_length', $curlinfo)

                && $curlinfo['download_content_length'] >= 0) {

            // we received a correct header and at least can tell the file size

            $file->set_synchronized(null, $curlinfo['download_content_length']);

            return true;

        }

        $file->set_missingsource();

        return true;

    }

    /**

     * Repository method to serve the referenced file

     *

     * @param stored_file $storedfile the file that contains the reference

     * @param int $lifetime Number of seconds before the file should expire from caches (null means $CFG->filelifetime)

     * @param int $filter 0 (default)=no filtering, 1=all files, 2=html files only

     * @param bool $forcedownload If true (default false), forces download of file rather than view in browser/plugin

     * @param array $options additional options affecting the file serving

     */

    public function send_file($stored_file, $lifetime=null , $filter=0, $forcedownload=false, ?array $options = null) {

        $ref = $this->unserialize_reference($stored_file->get_reference());

        if (isset($ref->url) && $url = $this->appendtoken($ref->url)) {

            header('Location: ' . $url);

        } else {

            send_file_not_found();

        }

    }

    /**

     * Add Instance settings input to Moodle form

     *

     * @param MoodleQuickForm $mform

     */

    public static function instance_config_form($mform) {

        global $CFG;

        require_once("{$CFG->dirroot}/user/profile/lib.php");

        $mform->addElement('text', 'equella_url', get_string('equellaurl', 'repository_equella'));

        $mform->setType('equella_url', PARAM_URL);

        $strrequired = get_string('required');

        $mform->addRule('equella_url', $strrequired, 'required', null, 'client');

        $userfieldoptions = ['default' => get_string('equellausername', 'repository_equella')];

        foreach (profile_get_custom_fields() as $field) {

            if ($field->datatype != 'text') {

                continue;

            }

            $userfieldoptions[$field->shortname] = format_string($field->name, true, ['context' => context_system::instance()]);

        }

        $mform->addElement('select', 'equella_userfield', get_string('equellauserfield', 'repository_equella'), $userfieldoptions);

        $mform->setDefault('equella_userfield', $userfieldoptions['default']);

        $mform->addHelpButton('equella_userfield', 'equellauserfield', 'repository_equella');

        $mform->addElement('text', 'equella_options', get_string('equellaoptions', 'repository_equella'));

        $mform->setType('equella_options', PARAM_NOTAGS);

        $choices = array(

            'none' => get_string('restrictionnone', 'repository_equella'),

            'itemonly' => get_string('restrictionitemsonly', 'repository_equella'),

            'attachmentonly' => get_string('restrictionattachmentsonly', 'repository_equella'),

        );

        $mform->addElement('select', 'equella_select_restriction', get_string('selectrestriction', 'repository_equella'), $choices);

        $mform->addElement('header', 'groupheader',

            get_string('group', 'repository_equella', get_string('groupdefault', 'repository_equella')));

        $mform->addElement('text', 'equella_shareid', get_string('sharedid', 'repository_equella'));

        $mform->setType('equella_shareid', PARAM_RAW);

        $mform->addRule('equella_shareid', $strrequired, 'required', null, 'client');

        $mform->addElement('text', 'equella_sharedsecret', get_string('sharedsecrets', 'repository_equella'));

        $mform->setType('equella_sharedsecret', PARAM_RAW);

        $mform->addRule('equella_sharedsecret', $strrequired, 'required', null, 'client');

        foreach (self::get_all_editing_roles() as $role) {

            $mform->addElement('header', 'groupheader_'.$role->shortname, get_string('group', 'repository_equella',

                role_get_name($role)));

            $mform->addElement('text', "equella_{$role->shortname}_shareid", get_string('sharedid', 'repository_equella'));

            $mform->setType("equella_{$role->shortname}_shareid", PARAM_RAW);

            $mform->addElement('text', "equella_{$role->shortname}_sharedsecret",

                get_string('sharedsecrets', 'repository_equella'));

            $mform->setType("equella_{$role->shortname}_sharedsecret", PARAM_RAW);

        }

    }

    /**

     * Names of the instance settings

     *

     * @return array

     */

    public static function get_instance_option_names() {

        $rv = array('equella_url', 'equella_select_restriction', 'equella_options',

            'equella_shareid', 'equella_sharedsecret', 'equella_userfield',

        );

        foreach (self::get_all_editing_roles() as $role) {

            array_push($rv, "equella_{$role->shortname}_shareid");

            array_push($rv, "equella_{$role->shortname}_sharedsecret");

        }

        return $rv;

    }

    /**

     * Generate equella token

     *

     * @param string $username

     * @param string $shareid

     * @param string $sharedsecret

     * @return string

     */

    private static function getssotoken_raw($username, $shareid, $sharedsecret) {

        $time = time() . '000';

        return urlencode($username)

            . ':'

            . $shareid

            . ':'

            . $time

            . ':'

            . base64_encode(pack('H*', md5($username . $shareid . $time . $sharedsecret)));

    }

    /**

     * Append token

     *

     * @param string $url

     * @param $readwrite

     * @return string

     */

    private function appendtoken($url, $readwrite = null) {

        $ssotoken = $this->getssotoken($readwrite);

        if (!$ssotoken) {

            return false;

        }

        return $url . (strpos($url, '?') != false ? '&' : '?') . 'token=' . urlencode($ssotoken);

    }

    /**

     * Generate equella sso token

     *

     * @param string $readwrite

     * @return string

     */

    private function getssotoken($readwrite = 'read') {

        global $USER;

        if (empty($USER->username)) {

            return false;

        }

        $equellauserfield = $this->get_userfield_value();

        if ($readwrite == 'write') {

            foreach (self::get_all_editing_roles() as $role) {

                if (user_has_role_assignment($USER->id, $role->id, $this->context->id)) {

                    // See if the user has a role that is linked to an equella role.

                    $shareid = $this->get_option("equella_{$role->shortname}_shareid");

                    if (!empty($shareid)) {

                        return $this->getssotoken_raw($equellauserfield, $shareid,

                            $this->get_option("equella_{$role->shortname}_sharedsecret"));

                    }

                }

            }

        }

        // If we are only reading, use the unadorned shareid and secret.

        $shareid = $this->get_option('equella_shareid');

        if (!empty($shareid)) {

            return $this->getssotoken_raw($equellauserfield, $shareid, $this->get_option('equella_sharedsecret'));

        }

    }

    private static function get_all_editing_roles() {

        return get_roles_with_capability('moodle/course:manageactivities', CAP_ALLOW);

    }

    /**

     * Convert moodle mimetypes list to equella format

     *

     * @param string $value

     * @return string

     */

    private static function to_mime_type($value) {

        return mimeinfo('type', $value);

    }

    /**

     * Return the source information

     *

     * @param string $source

     * @return string|null

     */

    public function get_file_source_info($source) {

        $ref = json_decode(base64_decode($source));

        $filename  = clean_param($ref->filename, PARAM_FILE);

        return 'EQUELLA: ' . $filename;

    }

    /**

     * Return human readable reference information

     * {@link stored_file::get_reference()}

     *

     * @param string $reference

     * @param int $filestatus status of the file, 0 - ok, 666 - source missing

     * @return string

     */

    public function get_reference_details($reference, $filestatus = 0) {

        if (!$filestatus) {

            $ref = $this->unserialize_reference($reference);

            return $this->get_name(). ': '. ($ref->filename ?? '');

        } else {

            return get_string('lostsource', 'repository', '');

        }

    }

    /**

     * Is this repository accessing private data?

     *

     * @return bool

     */

    public function contains_private_data() {

        return false;

    }

    /**

     * Retrieve the userfield/username.

     *

     * @return string

     */

    public function get_userfield_value(): string {

        global $USER;

        $userfield = $this->get_option('equella_userfield');

        if ($userfield != 'default' && isset($USER->profile[$userfield])) {

            return $USER->profile[$userfield];

        } else {

            return $USER->username;

        }

    }

}