/**
* Send a service request to the tool consumer.
*
* @param string $type Message type value
* @param string $url URL to send request to
* @param string $xml XML of message request
*
* @return boolean True if the request successfully obtained a response
*/
private function doLTI11Service($type, $url, $xml)
{
$ok = false;
$this->extRequest = null;
$this->extRequestHeaders = '';
$this->extResponse = null;
$this->extResponseHeaders = '';
if (!empty($url)) {
$id = uniqid();
$xmlRequest = <<<EOD
<?xml version = "1.0" encoding = "UTF-8"?>
<imsx_POXEnvelopeRequest xmlns = "http://www.imsglobal.org/services/ltiv1p1/xsd/imsoms_v1p0">
<imsx_POXHeader>
<imsx_POXRequestHeaderInfo>
<imsx_version>V1.0</imsx_version>
<imsx_messageIdentifier>{$id}</imsx_messageIdentifier>
</imsx_POXRequestHeaderInfo>
</imsx_POXHeader>
<imsx_POXBody>
<{$type}Request>
{$xml}
</{$type}Request>
</imsx_POXBody>
</imsx_POXEnvelopeRequest>
EOD;
// Calculate body hash
$hash = base64_encode(sha1($xmlRequest, true));
$params = array('oauth_body_hash' => $hash);
// Add OAuth signature
$hmacMethod = new OAuth\OAuthSignatureMethod_HMAC_SHA1();
$consumer = new OAuth\OAuthConsumer($this->getConsumer()->getKey(), $this->getConsumer()->secret, null);
$req = OAuth\OAuthRequest::from_consumer_and_token($consumer, null, 'POST', $url, $params);
$req->sign_request($hmacMethod, $consumer, null);
$params = $req->get_parameters();
$header = $req->to_header();
$header .= "\nContent-Type: application/xml";
// Connect to tool consumer
$http = new HTTPMessage($url, 'POST', $xmlRequest, $header);
// Parse XML response
if ($http->send()) {
$this->extResponse = $http->response;
$this->extResponseHeaders = $http->responseHeaders;
try {
$this->extDoc = new DOMDocument();
$this->extDoc->loadXML($http->response);
$this->extNodes = $this->domnodeToArray($this->extDoc->documentElement);
if (isset($this->extNodes['imsx_POXHeader']['imsx_POXResponseHeaderInfo']['imsx_statusInfo']['imsx_codeMajor']) && $this->extNodes['imsx_POXHeader']['imsx_POXResponseHeaderInfo']['imsx_statusInfo']['imsx_codeMajor'] === 'success') {
$ok = true;
}
} catch (\Exception $e) {
}
}
$this->extRequest = $http->request;
$this->extRequestHeaders = $http->requestHeaders;
}
return $ok;
}
/**
* Add the OAuth signature to an array of message parameters or to a header string.
*
* @return mixed Array of signed message parameters or header string
*/
public static function addSignature($endpoint, $consumerKey, $consumerSecret, $data, $method = 'POST', $type = null)
{
$params = array();
if (is_array($data)) {
$params = $data;
}
// Check for query parameters which need to be included in the signature
$queryParams = array();
$queryString = parse_url($endpoint, PHP_URL_QUERY);
if (!is_null($queryString)) {
$queryItems = explode('&', $queryString);
foreach ($queryItems as $item) {
if (strpos($item, '=') !== false) {
list($name, $value) = explode('=', $item);
$queryParams[urldecode($name)] = urldecode($value);
} else {
$queryParams[urldecode($item)] = '';
}
}
$params = $params + $queryParams;
}
if (!is_array($data)) {
// Calculate body hash
$hash = base64_encode(sha1($data, true));
$params['oauth_body_hash'] = $hash;
}
// Add OAuth signature
$hmacMethod = new OAuth\OAuthSignatureMethod_HMAC_SHA1();
$oauthConsumer = new OAuth\OAuthConsumer($consumerKey, $consumerSecret, null);
$oauthReq = OAuth\OAuthRequest::from_consumer_and_token($oauthConsumer, null, $method, $endpoint, $params);
$oauthReq->sign_request($hmacMethod, $oauthConsumer, null);
$params = $oauthReq->get_parameters();
// Remove parameters being passed on the query string
foreach (array_keys($queryParams) as $name) {
unset($params[$name]);
}
if (!is_array($data)) {
$header = $oauthReq->to_header();
if (empty($data)) {
if (!empty($type)) {
$header .= "\nAccept: {$type}";
}
} else {
if (isset($type)) {
$header .= "\nContent-Type: {$type}";
$header .= "\nContent-Length: " . strlen($data);
}
}
return $header;
} else {
return $params;
}
}
