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 file contains a class definition for the LISResults container resource

 *

 * @package    ltiservice_gradebookservices

 * @copyright  2017 Cengage Learning http://www.cengage.com

 * @author     Dirk Singels, Diego del Blanco, Claude Vervoort

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

 */

namespace ltiservice_gradebookservices\local\resources;

use ltiservice_gradebookservices\local\service\gradebookservices;

use mod_lti\local\ltiservice\resource_base;

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

/**

 * A resource implementing LISResult container.

 *

 * @package    ltiservice_gradebookservices

 * @copyright  2017 Cengage Learning http://www.cengage.com

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

 */

class results extends resource_base {

    /**

     * Class constructor.

     *

     * @param \ltiservice_gradebookservices\local\service\gradebookservices $service Service instance

     */

    public function __construct($service) {

        parent::__construct($service);

        $this->id = 'Result.collection';

        $this->template = '/{context_id}/lineitems/{item_id}/lineitem/results';

        $this->variables[] = 'Results.url';

        $this->formats[] = 'application/vnd.ims.lis.v2.resultcontainer+json';

        $this->methods[] = 'GET';

    }

    /**

     * Execute the request for this resource.

     *

     * @param \mod_lti\local\ltiservice\response $response  Response object for this request.

     */

    public function execute($response) {

        global $CFG, $DB;

        $params = $this->parse_template();

        $contextid = $params['context_id'];

        $itemid = $params['item_id'];

        $isget = $response->get_request_method() === self::HTTP_GET;

        // We will receive typeid when working with LTI 1.x, if not the we are in LTI 2.

        $typeid = optional_param('type_id', null, PARAM_INT);

        $scope = gradebookservices::SCOPE_GRADEBOOKSERVICES_RESULT_READ;

        try {

            if (!$this->check_tool($typeid, $response->get_request_data(), array($scope))) {

                throw new \Exception(null, 401);

            }

            $typeid = $this->get_service()->get_type()->id;

            if (!($course = $DB->get_record('course', array('id' => $contextid), 'id', IGNORE_MISSING))) {

                throw new \Exception("Not Found: Course {$contextid} doesn't exist", 404);

            }

            if (!$this->get_service()->is_allowed_in_context($typeid, $course->id)) {

                throw new \Exception('Not allowed in context', 403);

            }

            if (!$DB->record_exists('grade_items', array('id' => $itemid))) {

                throw new \Exception("Not Found: Grade item {$itemid} doesn't exist", 404);

            }

            $item = $this->get_service()->get_lineitem($contextid, $itemid, $typeid);

            if ($item === false) {

                throw new \Exception('Line item does not exist', 404);

            }

            $gbs = gradebookservices::find_ltiservice_gradebookservice_for_lineitem($itemid);

            $ltilinkid = null;

            if (isset($item->iteminstance)) {

                $ltilinkid = $item->iteminstance;

            } else if ($gbs && isset($gbs->ltilinkid)) {

                $ltilinkid = $gbs->ltilinkid;

            }

            if ($ltilinkid != null) {

                if (is_null($typeid)) {

                    if (isset($item->iteminstance) && (!gradebookservices::check_lti_id($ltilinkid, $item->courseid,

                            $this->get_service()->get_tool_proxy()->id))) {

                        $response->set_code(403);

                        $response->set_reason("Invalid LTI id supplied.");

                        return;

                    }

                } else {

                    if (isset($item->iteminstance) && (!gradebookservices::check_lti_1x_id($ltilinkid, $item->courseid,

                            $typeid))) {

                        $response->set_code(403);

                        $response->set_reason("Invalid LTI id supplied.");

                        return;

                    }

                }

            }

            require_once($CFG->libdir.'/gradelib.php');

            switch ($response->get_request_method()) {

                case 'GET':

                    $useridfilter = optional_param('user_id', 0, PARAM_INT);

                    $limitnum = optional_param('limit', 0, PARAM_INT);

                    $limitfrom = optional_param('from', 0, PARAM_INT);

                    $typeid = optional_param('type_id', null, PARAM_TEXT);

                    $json = $this->get_json_for_get_request($item->id, $limitfrom, $limitnum,

                            $useridfilter, $typeid, $response);

                    $response->set_content_type($this->formats[0]);

                    $response->set_body($json);

                    break;

                default:  // Should not be possible.

                    $response->set_code(405);

                    $response->set_reason("Invalid request method specified.");

                    return;

            }

            $response->set_body($json);

        } catch (\Exception $e) {

            $response->set_code($e->getCode());

            $response->set_reason($e->getMessage());

        }

    }

    /**

     * Generate the JSON for a GET request.

     *

     * @param int    $itemid     Grade item instance ID

     * @param int $limitfrom  Offset for the first result to include in this paged set

     * @param int $limitnum   Maximum number of results to include in the response, ignored if zero

     * @param int    $useridfilter     The user id to filter the results.

     * @param int    $typeid     Lti tool typeid (or null)

     * @param \mod_lti\local\ltiservice\response $response   The response element needed to add a header.

     *

     * @return string

     */

    private function get_json_for_get_request($itemid, $limitfrom, $limitnum, $useridfilter, $typeid, $response) {

        if ($useridfilter > 0) {

            $grades = \grade_grade::fetch_all(array('itemid' => $itemid, 'userid' => $useridfilter));

        } else {

            $grades = \grade_grade::fetch_all(array('itemid' => $itemid));

        }

        $firstpage = null;

        $nextpage = null;

        $prevpage = null;

        $lastpage = null;

        if ($grades && isset($limitnum) && $limitnum > 0) {

            // Since we only display grades that have been modified, we need to filter first in order to support

            // paging.

            $resultgrades = array_filter($grades, function ($grade) {

                return !empty($grade->timemodified);

            });

            // We save the total count to calculate the last page.

            $totalcount = count($resultgrades);

            // We slice to the requested item offset to insure proper item is always first, and we always return

            // first pageset of any remaining items.

            $grades = array_slice($resultgrades, $limitfrom);

            if (count($grades) > 0) {

                $pagedgrades = array_chunk($grades, $limitnum);

                $pageset = 0;

                $grades = $pagedgrades[$pageset];

            }

            if ($limitfrom >= $totalcount || $limitfrom < 0) {

                $outofrange = true;

            } else {

                $outofrange = false;

            }

            $limitprev = $limitfrom - $limitnum >= 0 ? $limitfrom - $limitnum : 0;

            $limitcurrent = $limitfrom;

            $limitlast = $totalcount - $limitnum + 1 >= 0 ? $totalcount - $limitnum + 1 : 0;

            $limitfrom += $limitnum;

            $baseurl = new \moodle_url($this->get_endpoint());

            if (is_null($typeid)) {

                $baseurl->param('limit', $limitnum);

                if (($limitfrom <= $totalcount - 1) && (!$outofrange)) {

                    $nextpage = new \moodle_url($baseurl, ['from' => $limitfrom]);

                }

                $firstpage = new \moodle_url($baseurl, ['from' => 0]);

                $canonicalpage = new \moodle_url($baseurl, ['from' => $limitcurrent]);

                $lastpage = new \moodle_url($baseurl, ['from' => $limitlast]);

                if (($limitcurrent > 0) && (!$outofrange)) {

                    $prevpage = new \moodle_url($baseurl, ['from' => $limitprev]);

                }

            } else {

                $baseurl->params(['type_id' => $typeid, 'limit' => $limitnum]);

                if (($limitfrom <= $totalcount - 1) && (!$outofrange)) {

                    $nextpage = new \moodle_url($baseurl, ['from' => $limitfrom]);

                }

                $firstpage = new \moodle_url($baseurl, ['from' => 0]);

                $canonicalpage = new \moodle_url($baseurl, ['from' => $limitcurrent]);

                if (($limitcurrent > 0) && (!$outofrange)) {

                    $prevpage = new \moodle_url($baseurl, ['from' => $limitprev]);

                }

            }

        }

        $jsonresults = [];

        $lineitem = new lineitem($this->get_service());

        $endpoint = $lineitem->get_endpoint();

        if ($grades) {

            foreach ($grades as $grade) {

                if (!empty($grade->timemodified)) {

                    array_push($jsonresults, gradebookservices::result_for_json($grade, $endpoint, $typeid));

                }

            }

        }

        if (isset($canonicalpage) && ($canonicalpage)) {

            $links = 'Link: <' . $firstpage->out() . '>; rel=“first”';

            if (!is_null($prevpage)) {

                $links .= ', <' . $prevpage->out() . '>; rel=“prev”';

            }

            $links .= ', <' . $canonicalpage->out() . '>; rel=“canonical”';

            if (!is_null($nextpage)) {

                $links .= ', <' . $nextpage->out() . '>; rel=“next”';

            }

            $links .= ', <' . $lastpage->out() . '>; rel=“last”';

            $response->add_additional_header($links);

        }

        return json_encode($jsonresults);

    }

    /**

     * Parse a value for custom parameter substitution variables.

     *

     * @param string $value String to be parsed

     *

     * @return string

     */

    public function parse_value($value) {

        global $COURSE, $CFG;

        if (strpos($value, '$Results.url') !== false) {

            require_once($CFG->libdir . '/gradelib.php');

            $resolved = '';

            $this->params['context_id'] = $COURSE->id;

            $id = optional_param('id', 0, PARAM_INT); // Course Module ID.

            if (!empty($id)) {

                $cm = get_coursemodule_from_id('lti', $id, 0, false, MUST_EXIST);

                $id = $cm->instance;

                $item = grade_get_grades($COURSE->id, 'mod', 'lti', $id);

                if ($item && $item->items) {

                    $this->params['item_id'] = $item->items[0]->id;

                    $resolved = parent::get_endpoint();

                }

            }

            $value = str_replace('$Results.url', $resolved, $value);

        }

        return $value;

    }

}