Proyectos de Subversion Moodle

<?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");

   $good_lti_version = $good_lti_version || ($_REQUEST["lti_version"] == "LTI-2p0" or $_REQUEST["lti_version"] == "LTI-2.0");

   $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;

     }

}

?>