function __construct($parm = false, $usesession = true, $doredirect = true)
{
// If this request is not an LTI Launch, either
// give up or try to retrieve the context from session
if (!is_basic_lti_request()) {
if ($usesession === false) {
return;
}
if (strlen(session_id()) > 0) {
$row = $_SESSION['_basiclti_lti_row'];
if (isset($row)) {
$this->row = $row;
}
$context_id = $_SESSION['_basiclti_lti_context_id'];
if (isset($context_id)) {
$this->context_id = $context_id;
}
$info = $_SESSION['_basic_lti_context'];
if (isset($info)) {
$this->info = $info;
$this->valid = true;
return;
}
$this->message = "Could not find context in session";
return;
}
$this->message = "Session not available";
return;
}
// Insure we have a valid launch
if (empty($_REQUEST["oauth_consumer_key"])) {
$this->message = "Missing oauth_consumer_key in request";
return;
}
$oauth_consumer_key = $_REQUEST["oauth_consumer_key"];
// Find the secret - either form the parameter as a string or
// look it up in a database from parameters we are given
$secret = false;
$row = false;
if (is_string($parm)) {
$secret = $parm;
} else {
if (!is_array($parm)) {
$this->message = "Constructor requires a secret or database information.";
return;
}
}
// Verify the message signature
$store = new ltiprovider\TrivialOAuthDataStore();
$store->add_consumer($oauth_consumer_key, $secret);
$server = new ltiprovider\OAuthServer($store);
$method = new ltiprovider\OAuthSignatureMethod_HMAC_SHA1();
$server->add_signature_method($method);
$request = ltiprovider\OAuthRequest::from_request();
$this->basestring = $request->get_signature_base_string();
try {
$server->verify_request($request);
$this->valid = true;
} catch (Exception $e) {
$this->message = $e->getMessage();
return;
}
// Store the launch information in the session for later
$newinfo = array();
foreach ($_POST as $key => $value) {
if ($key == "basiclti_submit") {
continue;
}
if (strpos($key, "oauth_") === false) {
$newinfo[$key] = $value;
continue;
}
if ($key == "oauth_consumer_key") {
$newinfo[$key] = $value;
continue;
}
}
//Added abertranb to decode base 64 20120801
if (isset($newinfo['custom_lti_message_encoded_base64']) && $newinfo['custom_lti_message_encoded_base64'] == 1) {
$newinfo = $this->decodeBase64($newinfo);
}
$this->info = $newinfo;
if ($usesession == true and strlen(session_id()) > 0) {
$_SESSION['_basic_lti_context'] = $this->info;
unset($_SESSION['_basiclti_lti_row']);
unset($_SESSION['_basiclti_lti_context_id']);
if ($this->row) {
$_SESSION['_basiclti_lti_row'] = $this->row;
}
if ($this->context_id) {
$_SESSION['_basiclti_lti_context_id'] = $this->context_id;
}
}
if ($this->valid && $doredirect) {
$this->redirect();
$this->complete = true;
}
}
function signOnly($oldparms, $endpoint, $method, $oauth_consumer_key, $oauth_consumer_secret)
{
global $last_base_string;
$parms = $oldparms;
$test_token = '';
$hmac_method = new ltiprovider\OAuthSignatureMethod_HMAC_SHA1();
$test_consumer = new ltiprovider\OAuthConsumer($oauth_consumer_key, $oauth_consumer_secret, NULL);
$acc_req = ltiprovider\OAuthRequest::from_consumer_and_token($test_consumer, $test_token, $method, $endpoint, $parms);
$acc_req->sign_request($hmac_method, $test_consumer, $test_token);
// Pass this back up "out of band" for debugging
$last_base_string = $acc_req->get_signature_base_string();
$newparms = $acc_req->get_parameters();
return $newparms;
}
