/enrol/lti/ims-blti/blti.php
PHP | 277 lines | 222 code | 34 blank | 21 comment | 57 complexity | 1210121969364c8438e219f993a40ae4 MD5 | raw file
- <?php
- require_once($CFG->dirroot . '/enrol/lti/ims-blti/OAuth.php');
- require_once($CFG->dirroot . '/enrol/lti/ims-blti/TrivialOAuthDataStore.php');
- // Returns true if this is a Basic LTI message
- // with minimum values to meet the protocol
- function is_basic_lti_request() {
- $good_message_type = $_REQUEST["lti_message_type"] == "basic-lti-launch-request";
- $good_lti_version = ($_REQUEST["lti_version"] == "LTI-1p0" or $_REQUEST["lti_version"] == "LTI-1.0");
- $resource_link_id = $_REQUEST["resource_link_id"];
- if ($good_message_type and $good_lti_version and isset($resource_link_id) ) return(true);
- return false;
- }
- // Basic LTI Class that does the setup and provides utility
- // functions
- class BLTI {
- public $valid = false;
- public $complete = false;
- public $message = false;
- public $basestring = false;
- public $info = false;
- public $row = false;
- public $context_id = false; // Override context_id
- function __construct($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 TrivialOAuthDataStore();
- $store->add_consumer($oauth_consumer_key, $secret);
- $server = new OAuthServer($store);
- $method = new OAuthSignatureMethod_HMAC_SHA1();
- $server->add_signature_method($method);
- $request = 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();
- $this->complete = true;
- }
- }
- function addSession($location) {
- if ( ini_get('session.use_cookies') == 0 ) {
- if ( strpos($location,'?') > 0 ) {
- $location = $location . '&';
- } else {
- $location = $location . '?';
- }
- $location = $location . session_name() . '=' . session_id();
- }
- return $location;
- }
- function isInstructor() {
- $roles = $this->info['roles'];
- $roles = strtolower($roles);
- if ( ! ( strpos($roles,"instructor") === false ) ) return true;
- if ( ! ( strpos($roles,"administrator") === false ) ) return true;
- return false;
- }
- function getUserEmail() {
- # set default email in the event privacy settings don't pass in email.
- $email = $this->info['user_id'] . "@ltiuser.com";
- if ( isset($this->info['lis_person_contact_email_primary']) ) $email = $this->info['lis_person_contact_email_primary'];
- # Sakai Hack
- if ( isset($this->info['lis_person_contact_emailprimary']) ) $email = $this->info['lis_person_contact_emailprimary'];
- return $email;
- }
- function getUserShortName() {
- $email = $this->getUserEmail();
- $givenname = $this->info['lis_person_name_given'];
- $familyname = $this->info['lis_person_name_family'];
- $fullname = $this->info['lis_person_name_full'];
- if ( strlen($email) > 0 ) return $email;
- if ( strlen($givenname) > 0 ) return $givenname;
- if ( strlen($familyname) > 0 ) return $familyname;
- return $this->getUserName();
- }
- function getUserName() {
- $givenname = $this->info['lis_person_name_given'];
- $familyname = $this->info['lis_person_name_family'];
- $fullname = $this->info['lis_person_name_full'];
- if ( strlen($fullname) > 0 ) return $fullname;
- if ( strlen($familyname) > 0 and strlen($givenname) > 0 ) return $givenname + $familyname;
- if ( strlen($givenname) > 0 ) return $givenname;
- if ( strlen($familyname) > 0 ) return $familyname;
- return $this->getUserEmail();
- }
- function getUserKey() {
- $oauth = $this->info['oauth_consumer_key'];
- $id = $this->info['user_id'];
- if ( strlen($id) > 0 and strlen($oauth) > 0 ) return $oauth . ':' . $id;
- return false;
- }
- function getUserImage() {
- $image = $this->info['user_image'];
- if ( strlen($image) > 0 ) return $image;
- $email = $this->getUserEmail();
- if ( $email === false ) return false;
- $size = 40;
- $grav_url = $_SERVER['HTTPS'] ? 'https://' : 'http://';
- $grav_url = $grav_url . "www.gravatar.com/avatar.php?gravatar_id=".md5( strtolower($email) )."&size=".$size;
- return $grav_url;
- }
- function getResourceKey() {
- $oauth = $this->info['oauth_consumer_key'];
- $id = $this->info['resource_link_id'];
- if ( strlen($id) > 0 and strlen($oauth) > 0 ) return $oauth . ':' . $id;
- return false;
- }
- function getResourceTitle() {
- $title = $this->info['resource_link_title'];
- if ( strlen($title) > 0 ) return $title;
- return false;
- }
- function getConsumerKey() {
- $oauth = $this->info['oauth_consumer_key'];
- return $oauth;
- }
- function getCourseKey() {
- if ( $this->context_id ) return $this->context_id;
- $oauth = $this->info['oauth_consumer_key'];
- $id = $this->info['context_id'];
- if ( strlen($id) > 0 and strlen($oauth) > 0 ) return $oauth . ':' . $id;
- return false;
- }
- function getCourseName() {
- $label = $this->info['context_label'];
- $title = $this->info['context_title'];
- $id = $this->info['context_id'];
- if ( strlen($label) > 0 ) return $label;
- if ( strlen($title) > 0 ) return $title;
- if ( strlen($id) > 0 ) return $id;
- return false;
- }
- // TODO: Add javasript version if headers are already sent
- function redirect() {
- $host = $_SERVER['HTTP_HOST'];
- $uri = $_SERVER['PHP_SELF'];
- $location = $_SERVER['HTTPS'] ? 'https://' : 'http://';
- $location = $location . $host . $uri;
- $location = $this->addSession($location);
- header("Location: $location");
- }
- function dump() {
- if ( ! $this->valid or $this->info == false ) return "Context not valid\n";
- $ret = "";
- if ( $this->isInstructor() ) {
- $ret .= "isInstructor() = true\n";
- } else {
- $ret .= "isInstructor() = false\n";
- }
- $ret .= "getUserKey() = ".$this->getUserKey()."\n";
- $ret .= "getUserEmail() = ".$this->getUserEmail()."\n";
- $ret .= "getUserShortName() = ".$this->getUserShortName()."\n";
- $ret .= "getUserName() = ".$this->getUserName()."\n";
- $ret .= "getUserImage() = ".$this->getUserImage()."\n";
- $ret .= "getResourceKey() = ".$this->getResourceKey()."\n";
- $ret .= "getResourceTitle() = ".$this->getResourceTitle()."\n";
- $ret .= "getCourseName() = ".$this->getCourseName()."\n";
- $ret .= "getCourseKey() = ".$this->getCourseKey()."\n";
- $ret .= "getConsumerKey() = ".$this->getConsumerKey()."\n";
- return $ret;
- }
- /**
- * Data submitter are in base64 then we have to decode
- * @author Antoni Bertran (antoni@tresipunt.com)
- * @param $info array
- * @date 20120801
- */
- function decodeBase64($info) {
- $keysNoEncode = array("lti_version", "lti_message_type", "tool_consumer_instance_description", "tool_consumer_instance_guid", "oauth_consumer_key", "custom_lti_message_encoded_base64", "oauth_nonce", "oauth_version", "oauth_callback", "oauth_timestamp", "basiclti_submit", "oauth_signature_method", "ext_ims_lis_memberships_id", "ext_ims_lis_memberships_url");
- foreach ($info as $key => $item){
- if (!in_array($key, $keysNoEncode))
- $info[$key] = base64_decode($item);
- }
- return $info;
- }
- }
- ?>