class.ilLTIConsumerResultService.php

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<?php

declare(strict_types=1);
/******************************************************************************
 *
 * This file is part of ILIAS, a powerful learning management system.
 *
 * ILIAS is licensed with the GPL-3.0, you should have received a copy
 * of said license along with the source code.
 *
 * If this is not the case or you just want to try ILIAS, you'll find
 * us at:
 *      https://www.ilias.de
 *      https://github.com/ILIAS-eLearning
 *
 *****************************************************************************/
class ilLTIConsumerResultService
{
    protected ?ilLTIConsumerResult $result = null;

    protected int $availability = 0;

    protected float $mastery_score = 1;

    protected array $fields = array();

    protected string $message_ref_id = '';
    protected string $operation = '';


    public function getMasteryScore(): float
    {
        return $this->mastery_score;
    }

    public function setMasteryScore(float $mastery_score): void
    {
        $this->mastery_score = $mastery_score;
    }

    public function getAvailability(): int
    {
        return $this->availability;
    }

    public function setAvailability(int $availability): void
    {
        $this->availability = $availability;
    }

    public function isAvailable(): bool
    {
        if ($this->availability == 0) {
            return false;
        }
        return true;
    }

    public function handleRequest(): void
    {
        try {
            // get the request as xml
            $xml = simplexml_load_file('php://input');
            $this->message_ref_id = (string) $xml->imsx_POXHeader->imsx_POXRequestHeaderInfo->imsx_messageIdentifier;
            //            $request = current($xml->imsx_POXBody->children());
            $request = $xml->imsx_POXBody->children()[0];
            $this->operation = str_replace('Request', '', $request->getName());

            $token = ilCmiXapiAuthToken::getInstanceByToken((string) $request->resultRecord->sourcedGUID->sourcedId);

            $this->result = ilLTIConsumerResult::getByKeys($token->getObjId(), $token->getUsrId(), false);
            if (empty($this->result)) {
                $this->respondUnauthorized("lti_consumer_results_id not found!");
                return;
            }


            // check the object status
            $this->readProperties($this->result->obj_id);

            if (!$this->isAvailable()) {
                $this->respondUnsupported();
                return;
            }

            // Verify the signature
            $this->readFields($this->result->obj_id);
            $result = $this->checkSignature($this->fields['KEY'], $this->fields['SECRET']);
            if ($result instanceof Exception) {
                $this->respondUnauthorized($result->getMessage());
                return;
            }

            // Dispatch the operation
            switch ($this->operation) {
                case 'readResult':
                    $this->readResult($request);
                    break;

                case 'replaceResult':
                    $this->replaceResult($request);
                    $this->updateLP();
                    break;

                case 'deleteResult':
                    $this->deleteResult($request);
                    $this->updateLP();
                    break;

                default:
                    $this->respondUnknown();
                    break;
            }
        } catch (Exception $exception) {
            $this->respondBadRequest($exception->getMessage());
        }
    }

    protected function readResult(\SimpleXMLElement $request): void
    {
        $response = $this->loadResponse('readResult.xml');
        $response = str_replace('{message_id}', md5((string) rand(0, 999_999_999)), $response);
        $response = str_replace('{message_ref_id}', $this->message_ref_id, $response);
        $response = str_replace('{operation}', $this->operation, $response);
        $response = str_replace('{result}', (string) $this->result->result, $response);

        header('Content-type: application/xml');
        echo $response;
    }

    protected function replaceResult(\SimpleXMLElement $request): void
    {
        $result = (string) $request->resultRecord->result->resultScore->textString;
        if (!is_numeric($result)) {
            $code = "failure";
            $severity = "status";
            $description = "The result is not a number.";
        } elseif ($result < 0 or $result > 1) {
            $code = "failure";
            $severity = "status";
            $description = "The result is out of range from 0 to 1.";
        } else {
            $this->result->result = (float) $result;
            $this->result->save();

            if ($result >= $this->getMasteryScore()) {
                $lp_status = ilLPStatus::LP_STATUS_COMPLETED_NUM;
            } else {
                $lp_status = ilLPStatus::LP_STATUS_IN_PROGRESS_NUM;
            }
            $lp_percentage = (int) round(100 * $result);

            //            Mantis #37080
            ilLPStatus::writeStatus($this->result->obj_id, $this->result->usr_id, $lp_status, $lp_percentage, true);

            $code = "success";
            $severity = "status";
            $description = sprintf("Score for %s is now %s", $this->result->id, $this->result->result);
        }

        $response = $this->loadResponse('replaceResult.xml');
        $response = str_replace('{message_id}', md5((string) rand(0, 999_999_999)), $response);
        $response = str_replace('{message_ref_id}', $this->message_ref_id, $response);
        $response = str_replace('{operation}', $this->operation, $response);
        $response = str_replace('{code}', $code, $response);
        $response = str_replace('{severity}', $severity, $response);
        $response = str_replace('{description}', $description, $response);

        header('Content-type: application/xml');
        echo $response;
    }

    protected function deleteResult(\SimpleXMLElement $request): void
    {
        $this->result->result = null;
        $this->result->save();

        $lp_status = ilLPStatus::LP_STATUS_IN_PROGRESS_NUM;
        $lp_percentage = 0;
        ilLPStatus::writeStatus($this->result->obj_id, $this->result->usr_id, $lp_status, $lp_percentage, true);

        $code = "success";
        $severity = "status";

        $response = $this->loadResponse('deleteResult.xml');
        $response = str_replace('{message_id}', md5((string) rand(0, 999_999_999)), $response);
        $response = str_replace('{message_ref_id}', $this->message_ref_id, $response);
        $response = str_replace('{operation}', $this->operation, $response);
        $response = str_replace('{code}', $code, $response);
        $response = str_replace('{severity}', $severity, $response);

        header('Content-type: application/xml');
        echo $response;
    }


    protected function loadResponse($a_name): string
    {
        return file_get_contents('./Modules/LTIConsumer/responses/' . $a_name);
    }


    protected function respondUnsupported(): void
    {
        $response = $this->loadResponse('unsupported.xml');
        $response = str_replace('{message_id}', md5((string) rand(0, 999_999_999)), $response);
        $response = str_replace('{message_ref_id}', $this->message_ref_id, $response);
        $response = str_replace('{operation}', $this->operation, $response);

        header('Content-type: application/xml');
        echo $response;
    }

    protected function respondUnknown(): void
    {
        $response = $this->loadResponse('unknown.xml');
        $response = str_replace('{message_id}', md5((string) rand(0, 999_999_999)), $response);
        $response = str_replace('{message_ref_id}', $this->message_ref_id, $response);
        $response = str_replace('{operation}', $this->operation, $response);

        header('Content-type: application/xml');
        echo $response;
    }

    protected function respondBadRequest(?string $message = null): void
    {
        header('HTTP/1.1 400 Bad Request');
        header('Content-type: text/plain');
        if (isset($message)) {
            echo $message;
        } else {
            echo 'This is not a well-formed LTI Basic Outcomes Service request.';
        }
    }

    protected function respondUnauthorized(?string $message = null): void
    {
        header('HTTP/1.1 401 Unauthorized');
        header('Content-type: text/plain');
        if (isset($message)) {
            echo $message;
        } else {
            echo 'This request could not be authorized.';
        }
    }

    public function readProperties(int $a_obj_id): void
    {
        global $DIC;

        $query = "
                        SELECT lti_ext_provider.availability, lti_consumer_settings.mastery_score 
                        FROM lti_ext_provider, lti_consumer_settings
                        WHERE lti_ext_provider.id = lti_consumer_settings.provider_id
                        AND lti_consumer_settings.obj_id = %s
                ";

        $res = $DIC->database()->queryF($query, array('integer'), array($a_obj_id));

        if ($row = $DIC->database()->fetchAssoc($res)) {
            //$this->properties = $row;
            $this->setAvailability((int) $row['availability']);
            $this->setMasteryScore((float) $row['mastery_score']);
        }
    }

    private function readFields(int $a_obj_id): void
    {
        global $DIC;

        $query = "
                        SELECT lti_ext_provider.provider_key, lti_ext_provider.provider_secret, lti_consumer_settings.launch_key, lti_consumer_settings.launch_secret
                        FROM lti_ext_provider, lti_consumer_settings
                        WHERE lti_ext_provider.id = lti_consumer_settings.provider_id
                        AND lti_consumer_settings.obj_id = %s
                ";

        $res = $DIC->database()->queryF($query, array('integer'), array($a_obj_id));

        while ($row = $DIC->database()->fetchAssoc($res)) {
            if (strlen($row["launch_key"]) > 0) {
                $this->fields["KEY"] = $row["launch_key"];
            } else {
                $this->fields["KEY"] = $row["provider_key"];
            }
            if (strlen($row["launch_key"]) > 0) {
                $this->fields["SECRET"] = $row["launch_secret"];
            } else {
                $this->fields["SECRET"] = $row["provider_secret"];
            }
        }
    }

    private function checkSignature(string $a_key, string $a_secret)
    {
        $store = new TrivialOAuthDataStore();
        $store->add_consumer($a_key, $a_secret);

        $server = new \ILIAS\LTIOAuth\OAuthServer($store);
        $method = new \ILIAS\LTIOAuth\OAuthSignatureMethod_HMAC_SHA1();
        $server->add_signature_method($method);

        $request = \ILIAS\LTIOAuth\OAuthRequest::from_request();
        try {
            $server->verify_request($request);
        } catch (Exception $e) {
            return $e;
        }
        return true;
    }

    protected function updateLP(): void
    {
        if (!($this->result instanceof ilLTIConsumerResult)) {
            return;
        }

        ilLPStatusWrapper::_updateStatus($this->result->getObjId(), $this->result->getUsrId());
    }
}