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Long Term Support Release

  • Bug fixes for general core bugs in 4.1.x will end 13 November 2023 (12 months).
  • Bug fixes for security issues in 4.1.x will end 10 November 2025 (36 months).
  • PHP version: minimum PHP 7.4.0 Note: minimum PHP version has increased since Moodle 4.0. PHP 8.0.x is supported too.
<?php

namespace Packback\Lti1p3;

> use Exception;
use Firebase\JWT\JWT;
> use GuzzleHttp\Client; use Packback\Lti1p3\Interfaces\ICache; > use GuzzleHttp\Exception\ClientException; use Packback\Lti1p3\Interfaces\IHttpClient; > use GuzzleHttp\Psr7\Response;
< use Packback\Lti1p3\Interfaces\IHttpClient; < use Packback\Lti1p3\Interfaces\IHttpException; < use Packback\Lti1p3\Interfaces\IHttpResponse;
use Packback\Lti1p3\Interfaces\ILtiServiceConnector; use Packback\Lti1p3\Interfaces\IServiceRequest; class LtiServiceConnector implements ILtiServiceConnector { public const NEXT_PAGE_REGEX = '/<([^>]*)>; ?rel="next"/i'; private $cache; private $client; private $debuggingMode = false; public function __construct( ICache $cache,
< IHttpClient $client
> Client $client
) { $this->cache = $cache; $this->client = $client; } public function setDebuggingMode(bool $enable): void { $this->debuggingMode = $enable; } public function getAccessToken(ILtiRegistration $registration, array $scopes) { // Get a unique cache key for the access token $accessTokenKey = $this->getAccessTokenCacheKey($registration, $scopes); // Get access token from cache if it exists $accessToken = $this->cache->getAccessToken($accessTokenKey); if ($accessToken) { return $accessToken; } // Build up JWT to exchange for an auth token $clientId = $registration->getClientId(); $jwtClaim = [ 'iss' => $clientId, 'sub' => $clientId, 'aud' => $registration->getAuthServer(), 'iat' => time() - 5, 'exp' => time() + 60, 'jti' => 'lti-service-token'.hash('sha256', random_bytes(64)), ]; // Sign the JWT with our private key (given by the platform on registration) $jwt = JWT::encode($jwtClaim, $registration->getToolPrivateKey(), 'RS256', $registration->getKid()); // Build auth token request headers $authRequest = [ 'grant_type' => 'client_credentials', 'client_assertion_type' => 'urn:ietf:params:oauth:client-assertion-type:jwt-bearer', 'client_assertion' => $jwt, 'scope' => implode(' ', $scopes), ]; // Get Access $request = new ServiceRequest( ServiceRequest::METHOD_POST, $registration->getAuthTokenUrl(), ServiceRequest::TYPE_AUTH ); $request->setPayload(['form_params' => $authRequest]); $response = $this->makeRequest($request); $tokenData = $this->getResponseBody($response); // Cache access token $this->cache->cacheAccessToken($accessTokenKey, $tokenData['access_token']); return $tokenData['access_token']; } public function makeRequest(IServiceRequest $request) { $response = $this->client->request( $request->getMethod(), $request->getUrl(), $request->getPayload() ); if ($this->debuggingMode) { $this->logRequest( $request, $this->getResponseHeaders($response), $this->getResponseBody($response) ); } return $response; }
< public function getResponseHeaders(IHttpResponse $response): ?array
> public function getResponseHeaders(Response $response): ?array
{ $responseHeaders = $response->getHeaders(); array_walk($responseHeaders, function (&$value) { $value = $value[0]; }); return $responseHeaders; }
< public function getResponseBody(IHttpResponse $response): ?array
> public function getResponseBody(Response $response): ?array
{ $responseBody = (string) $response->getBody(); return json_decode($responseBody, true); } public function makeServiceRequest( ILtiRegistration $registration, array $scopes, IServiceRequest $request, bool $shouldRetry = true ): array { $request->setAccessToken($this->getAccessToken($registration, $scopes)); try { $response = $this->makeRequest($request);
< } catch (IHttpException $e) {
> } catch (ClientException $e) {
$status = $e->getResponse()->getStatusCode(); // If the error was due to invalid authentication and the request // should be retried, clear the access token and retry it. if ($status === 401 && $shouldRetry) { $key = $this->getAccessTokenCacheKey($registration, $scopes); $this->cache->clearAccessToken($key); return $this->makeServiceRequest($registration, $scopes, $request, false); } throw $e; } return [ 'headers' => $this->getResponseHeaders($response), 'body' => $this->getResponseBody($response), 'status' => $response->getStatusCode(), ]; } public function getAll( ILtiRegistration $registration, array $scopes, IServiceRequest $request, string $key = null ): array { if ($request->getMethod() !== ServiceRequest::METHOD_GET) {
< throw new \Exception('An invalid method was specified by an LTI service requesting all items.');
> throw new Exception('An invalid method was specified by an LTI service requesting all items.');
} $results = []; $nextUrl = $request->getUrl(); while ($nextUrl) { $response = $this->makeServiceRequest($registration, $scopes, $request); $page_results = $key === null ? ($response['body'] ?? []) : ($response['body'][$key] ?? []); $results = array_merge($results, $page_results); $nextUrl = $this->getNextUrl($response['headers']); if ($nextUrl) { $request->setUrl($nextUrl); } } return $results; } private function logRequest( IServiceRequest $request, array $responseHeaders, ?array $responseBody ): void { $contextArray = [ 'request_method' => $request->getMethod(), 'request_url' => $request->getUrl(), 'response_headers' => $responseHeaders, 'response_body' => json_encode($responseBody), ]; $requestBody = $request->getPayload()['body'] ?? null; if (!empty($requestBody)) { $contextArray['request_body'] = $requestBody; } error_log(implode(' ', array_filter([ $request->getErrorPrefix(), json_decode($requestBody)->userId ?? null, print_r($contextArray, true), ]))); } private function getAccessTokenCacheKey(ILtiRegistration $registration, array $scopes) { sort($scopes); $scopeKey = md5(implode('|', $scopes)); return $registration->getIssuer().$registration->getClientId().$scopeKey; } private function getNextUrl(array $headers) { $subject = $headers['Link'] ?? ''; preg_match(static::NEXT_PAGE_REGEX, $subject, $matches); return $matches[1] ?? null; } }