/**
* Sign LTI Parameters
*
* @param array $parameters - parameters
* @param String $endPoint - HTTP URL end point
* @param String $method - HTTP method
* @param String $key - LTI Key
* @param String $secret - LTI Secret
* @return array - signed parameters
*/
public static function sign($parameters, $endPoint, $method, $key, $secret)
{
$params = $parameters;
if (!isset($params["lti_version"])) {
$params['lti_version'] = 'LTI-1p0';
}
if (!isset($params["lti_message_type"])) {
$params['lti_message_type'] = 'basic-lti-launch-request';
}
if (!isset($params["oauth_callback"])) {
$params['oauth_callback'] = 'about:blank';
}
$oauthConsumer = new OAuthConsumer($key, $secret);
$oauthRequest = OAuthRequest::createFromConsumerAndToken($oauthConsumer, null, $method, $endPoint, $params);
$oauthRequest->sign(new OAuthSignatureMethodHMACSHA1(), $oauthConsumer, null);
$newParams = $oauthRequest->getParameters();
foreach ($newParams as $k => $v) {
if (strpos($k, "oauth_") === 0) {
$params[$k] = $v;
}
}
return $params;
}
