355 lines
11 KiB
PHP
355 lines
11 KiB
PHP
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<?php
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require_once 'OAuth.php';
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require_once '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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{
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$good_message_type = $_REQUEST["lti_message_type"] == "basic-lti-launch-request";
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$good_lti_version = $_REQUEST["lti_version"] == "LTI-1p0";
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$resource_link_id = $_REQUEST["resource_link_id"];
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if ($good_message_type and $good_lti_version and isset($resource_link_id)) {
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return(true);
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}
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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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{
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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, $doredirect = true)
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{
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// If this request is not an LTI Launch, either
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// give up or try to retrieve the context from session
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if (! is_basic_lti_request()) {
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if ($usesession === false) {
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return;
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}
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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)) {
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$this->row = $row;
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}
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$context_id = $_SESSION['_basiclti_lti_context_id'];
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if (isset($context_id)) {
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$this->context_id = $context_id;
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}
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$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 = $parm;
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} elseif (! is_array($parm)) {
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$this->message = "Constructor requires a secret or database information.";
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return;
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} else {
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$sql = 'SELECT * FROM ' . $parm['table'] . ' WHERE ' .
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($parm['key_column'] ? $parm['key_column'] : 'oauth_consumer_key') .
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'=' .
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"'" . mysql_real_escape_string($oauth_consumer_key) . "'";
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$result = mysql_query($sql);
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$num_rows = mysql_num_rows($result);
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if ($num_rows != 1) {
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$this->message = "Your consumer is not authorized oauth_consumer_key=" . $oauth_consumer_key;
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return;
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} else {
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while ($row = mysql_fetch_assoc($result)) {
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$secret = $row[$parms['secret_column'] ? $parms['secret_column'] : 'secret'];
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$context_id = $row[$parms['context_column'] ? $parms['context_column'] : 'context_id'];
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if ($context_id) {
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$this->context_id = $context_id;
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}
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$this->row = $row;
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break;
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}
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if (! is_string($secret)) {
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$this->message = "Could not retrieve secret oauth_consumer_key=" . $oauth_consumer_key;
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return;
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}
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}
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}
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// Verify the message signature
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$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 = [];
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foreach ($_POST as $key => $value) {
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if ($key == "basiclti_submit") {
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continue;
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}
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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] = $value;
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continue;
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}
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}
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$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) {
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$_SESSION['_basiclti_lti_row'] = $this->row;
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}
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if ($this->context_id) {
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$_SESSION['_basiclti_lti_context_id'] = $this->context_id;
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}
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}
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if ($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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{
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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 $location;
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}
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function isInstructor()
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{
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$roles = $this->info['roles'];
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$roles = strtolower($roles);
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if (! ( strpos($roles, "instructor") === false )) {
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return true;
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}
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if (! ( strpos($roles, "administrator") === false )) {
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return true;
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}
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return false;
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}
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function getUserEmail()
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{
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$email = $this->info['lis_person_contact_email_primary'];
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if (strlen($email) > 0) {
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return $email;
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}
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# Sakai Hack
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$email = $this->info['lis_person_contact_emailprimary'];
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if (strlen($email) > 0) {
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return $email;
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}
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return false;
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}
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function getUserShortName()
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{
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$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) {
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return $email;
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}
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if (strlen($givenname) > 0) {
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return $givenname;
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}
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if (strlen($familyname) > 0) {
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return $familyname;
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}
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return $this->getUserName();
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}
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function getUserName()
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{
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$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) {
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return $fullname;
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}
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if (strlen($familyname) > 0 and strlen($givenname) > 0) {
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return $givenname + $familyname;
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}
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if (strlen($givenname) > 0) {
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return $givenname;
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}
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if (strlen($familyname) > 0) {
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return $familyname;
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}
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return $this->getUserEmail();
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}
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function getUserKey()
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{
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$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) {
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return $oauth . ':' . $id;
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}
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return false;
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}
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function getUserImage()
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{
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$image = $this->info['user_image'];
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if (strlen($image) > 0) {
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return $image;
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}
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$email = $this->getUserEmail();
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if ($email === false) {
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return false;
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}
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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 $grav_url;
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}
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function getResourceKey()
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{
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$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) {
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return $oauth . ':' . $id;
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}
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return false;
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}
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function getResourceTitle()
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{
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$title = $this->info['resource_link_title'];
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if (strlen($title) > 0) {
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return $title;
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}
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return false;
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}
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function getConsumerKey()
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{
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$oauth = $this->info['oauth_consumer_key'];
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return $oauth;
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}
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function getCourseKey()
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{
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if ($this->context_id) {
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return $this->context_id;
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}
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$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) {
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return $oauth . ':' . $id;
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}
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return false;
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}
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function getCourseName()
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{
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$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) {
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return $label;
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}
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if (strlen($title) > 0) {
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return $title;
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}
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if (strlen($id) > 0) {
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return $id;
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}
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return false;
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}
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// TODO: Add javasript version if headers are already sent
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function redirect()
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{
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$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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{
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if (! $this->valid or $this->info == false) {
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return "Context not valid\n";
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}
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$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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