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279 lines
10 KiB
279 lines
10 KiB
2 years ago
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<?php
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require_once($CFG->dirroot . '/enrol/lti/ims-blti/OAuth.php');
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require_once($CFG->dirroot . '/enrol/lti/ims-blti/TrivialOAuthDataStore.php');
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// Returns true if this is a Basic LTI message
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// with minimum values to meet the protocol
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function is_basic_lti_request() {
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$good_message_type = $_REQUEST["lti_message_type"] == "basic-lti-launch-request";
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$good_lti_version = ($_REQUEST["lti_version"] == "LTI-1p0" or $_REQUEST["lti_version"] == "LTI-1.0");
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$good_lti_version = $good_lti_version || ($_REQUEST["lti_version"] == "LTI-2p0" or $_REQUEST["lti_version"] == "LTI-2.0");
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$resource_link_id = $_REQUEST["resource_link_id"];
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if ($good_message_type and $good_lti_version and isset($resource_link_id) ) return(true);
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return false;
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}
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// Basic LTI Class that does the setup and provides utility
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// functions
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class BLTI {
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public $valid = false;
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public $complete = false;
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public $message = false;
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public $basestring = false;
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public $info = false;
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public $row = false;
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public $context_id = false; // Override context_id
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function __construct($parm=false, $usesession=true, $doredirect=true) {
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// If this request is not an LTI Launch, either
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// give up or try to retrieve the context from session
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if ( ! is_basic_lti_request() ) {
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if ( $usesession === false ) return;
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if ( strlen(session_id()) > 0 ) {
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$row = $_SESSION['_basiclti_lti_row'];
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if ( isset($row) ) $this->row = $row;
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$context_id = $_SESSION['_basiclti_lti_context_id'];
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if ( isset($context_id) ) $this->context_id = $context_id;
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$info = $_SESSION['_basic_lti_context'];
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if ( isset($info) ) {
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$this->info = $info;
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$this->valid = true;
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return;
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}
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$this->message = "Could not find context in session";
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return;
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}
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$this->message = "Session not available";
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return;
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}
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// Insure we have a valid launch
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if ( empty($_REQUEST["oauth_consumer_key"]) ) {
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$this->message = "Missing oauth_consumer_key in request";
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return;
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}
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$oauth_consumer_key = $_REQUEST["oauth_consumer_key"];
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// Find the secret - either form the parameter as a string or
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// look it up in a database from parameters we are given
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$secret = false;
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$row = false;
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if ( is_string($parm) ) {
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$secret = $parm;
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} else if ( ! is_array($parm) ) {
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$this->message = "Constructor requires a secret or database information.";
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return;
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}
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// Verify the message signature
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$store = new TrivialOAuthDataStore();
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$store->add_consumer($oauth_consumer_key, $secret);
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$server = new OAuthServer($store);
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$method = new OAuthSignatureMethod_HMAC_SHA1();
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$server->add_signature_method($method);
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$request = OAuthRequest::from_request();
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$this->basestring = $request->get_signature_base_string();
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try {
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$server->verify_request($request);
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$this->valid = true;
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} catch (Exception $e) {
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$this->message = $e->getMessage();
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return;
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}
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// Store the launch information in the session for later
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$newinfo = array();
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foreach($_POST as $key => $value ) {
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if ( $key == "basiclti_submit" ) continue;
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if ( strpos($key, "oauth_") === false ) {
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$newinfo[$key] = $value;
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continue;
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}
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if ( $key == "oauth_consumer_key" ) {
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$newinfo[$key] = $value;
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continue;
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}
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}
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//Added abertranb to decode base 64 20120801
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if (isset($newinfo['custom_lti_message_encoded_base64']) && $newinfo['custom_lti_message_encoded_base64']==1){
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$newinfo = $this->decodeBase64($newinfo);
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}
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$this->info = $newinfo;
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if ( $usesession == true and strlen(session_id()) > 0 ) {
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$_SESSION['_basic_lti_context'] = $this->info;
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unset($_SESSION['_basiclti_lti_row']);
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unset($_SESSION['_basiclti_lti_context_id']);
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if ( $this->row ) $_SESSION['_basiclti_lti_row'] = $this->row;
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if ( $this->context_id ) $_SESSION['_basiclti_lti_context_id'] = $this->context_id;
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}
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if ( $this->valid && $doredirect ) {
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$this->redirect();
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$this->complete = true;
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}
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}
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function addSession($location) {
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if ( ini_get('session.use_cookies') == 0 ) {
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if ( strpos($location,'?') > 0 ) {
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$location = $location . '&';
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} else {
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$location = $location . '?';
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}
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$location = $location . session_name() . '=' . session_id();
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}
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return $location;
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}
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function isInstructor() {
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$roles = $this->info['roles'];
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$roles = strtolower($roles);
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if ( ! ( strpos($roles,"instructor") === false ) ) return true;
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if ( ! ( strpos($roles,"administrator") === false ) ) return true;
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return false;
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}
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function getUserEmail() {
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# set default email in the event privacy settings don't pass in email.
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$email = $this->info['user_id'] . "@ltiuser.com";
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if ( isset($this->info['lis_person_contact_email_primary']) ) $email = $this->info['lis_person_contact_email_primary'];
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# Sakai Hack
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if ( isset($this->info['lis_person_contact_emailprimary']) ) $email = $this->info['lis_person_contact_emailprimary'];
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return $email;
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}
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function getUserShortName() {
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$email = $this->getUserEmail();
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$givenname = $this->info['lis_person_name_given'];
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$familyname = $this->info['lis_person_name_family'];
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$fullname = $this->info['lis_person_name_full'];
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if ( strlen($email) > 0 ) return $email;
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if ( strlen($givenname) > 0 ) return $givenname;
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if ( strlen($familyname) > 0 ) return $familyname;
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return $this->getUserName();
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}
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function getUserName() {
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$givenname = $this->info['lis_person_name_given'];
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$familyname = $this->info['lis_person_name_family'];
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$fullname = $this->info['lis_person_name_full'];
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if ( strlen($fullname) > 0 ) return $fullname;
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if ( strlen($familyname) > 0 and strlen($givenname) > 0 ) return $givenname + $familyname;
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if ( strlen($givenname) > 0 ) return $givenname;
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if ( strlen($familyname) > 0 ) return $familyname;
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return $this->getUserEmail();
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}
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function getUserKey() {
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$oauth = $this->info['oauth_consumer_key'];
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$id = $this->info['user_id'];
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if ( strlen($id) > 0 and strlen($oauth) > 0 ) return $oauth . ':' . $id;
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return false;
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}
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function getUserImage() {
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$image = $this->info['user_image'];
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if ( strlen($image) > 0 ) return $image;
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$email = $this->getUserEmail();
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if ( $email === false ) return false;
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$size = 40;
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$grav_url = $_SERVER['HTTPS'] ? 'https://' : 'http://';
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$grav_url = $grav_url . "www.gravatar.com/avatar.php?gravatar_id=".md5( strtolower($email) )."&size=".$size;
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return $grav_url;
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}
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function getResourceKey() {
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$oauth = $this->info['oauth_consumer_key'];
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$id = $this->info['resource_link_id'];
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if ( strlen($id) > 0 and strlen($oauth) > 0 ) return $oauth . ':' . $id;
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return false;
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}
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function getResourceTitle() {
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$title = $this->info['resource_link_title'];
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if ( strlen($title) > 0 ) return $title;
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return false;
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}
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function getConsumerKey() {
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$oauth = $this->info['oauth_consumer_key'];
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return $oauth;
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}
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function getCourseKey() {
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if ( $this->context_id ) return $this->context_id;
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$oauth = $this->info['oauth_consumer_key'];
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$id = $this->info['context_id'];
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if ( strlen($id) > 0 and strlen($oauth) > 0 ) return $oauth . ':' . $id;
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return false;
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}
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function getCourseName() {
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$label = $this->info['context_label'];
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$title = $this->info['context_title'];
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$id = $this->info['context_id'];
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if ( strlen($label) > 0 ) return $label;
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if ( strlen($title) > 0 ) return $title;
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if ( strlen($id) > 0 ) return $id;
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return false;
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}
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// TODO: Add javasript version if headers are already sent
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function redirect() {
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$host = $_SERVER['HTTP_HOST'];
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$uri = $_SERVER['PHP_SELF'];
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$location = $_SERVER['HTTPS'] ? 'https://' : 'http://';
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$location = $location . $host . $uri;
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$location = $this->addSession($location);
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header("Location: $location");
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}
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function dump() {
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if ( ! $this->valid or $this->info == false ) return "Context not valid\n";
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$ret = "";
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if ( $this->isInstructor() ) {
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$ret .= "isInstructor() = true\n";
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} else {
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$ret .= "isInstructor() = false\n";
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}
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$ret .= "getUserKey() = ".$this->getUserKey()."\n";
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$ret .= "getUserEmail() = ".$this->getUserEmail()."\n";
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$ret .= "getUserShortName() = ".$this->getUserShortName()."\n";
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$ret .= "getUserName() = ".$this->getUserName()."\n";
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$ret .= "getUserImage() = ".$this->getUserImage()."\n";
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$ret .= "getResourceKey() = ".$this->getResourceKey()."\n";
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$ret .= "getResourceTitle() = ".$this->getResourceTitle()."\n";
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$ret .= "getCourseName() = ".$this->getCourseName()."\n";
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$ret .= "getCourseKey() = ".$this->getCourseKey()."\n";
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$ret .= "getConsumerKey() = ".$this->getConsumerKey()."\n";
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return $ret;
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}
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/**
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* Data submitter are in base64 then we have to decode
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* @author Antoni Bertran (antoni@tresipunt.com)
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* @param $info array
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* @date 20120801
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*/
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function decodeBase64($info) {
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$keysNoEncode = array("lti_version", "lti_message_type", "tool_consumer_instance_description", "tool_consumer_instance_guid", "oauth_consumer_key", "custom_lti_message_encoded_base64", "oauth_nonce", "oauth_version", "oauth_callback", "oauth_timestamp", "basiclti_submit", "oauth_signature_method", "ext_ims_lis_memberships_id", "ext_ims_lis_memberships_url");
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foreach ($info as $key => $item){
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if (!in_array($key, $keysNoEncode))
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$info[$key] = base64_decode($item);
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}
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return $info;
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}
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}
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?>
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