UniZensusRPC.class.php

<?php
require_once "vendor/phpxmlrpc/xmlrpc.inc";
#require_once "lib/datei.inc.php";

class UniZensusRPC {

    var $timeout = 2;
    var $cache = 300;
    var $debug = 0;

    /**
     *
     */
    function __construct(){
        $this->client = new xmlrpc_client(Config::get()->UNIZENSUSPLUGIN_XMLRPC_ENDPOINT);
        $this->client->setDebug($this->debug);
    }

    function getCourseStatus($course_id, $user_id = null){
        $id = md5($course_id . $user_id);
        if (!is_null( ($cached_result = $this->getResultFromCache($id)) )){
            return $cached_result;
        }
        $result = array();
        $tstamp = date('Y-m-d-H-i');
        $hash = hash_hmac(
            'md5',
            $course_id.$tstamp.$user_id,
            Config::get()->UNIZENSUSPLUGIN_SHARED_SECRET1 . Config::get()->UNIZENSUSPLUGIN_SHARED_SECRET2
        );
        if (is_null($user_id)){
            $msg = new xmlrpcmsg(
                "info.course_status_v3",
                array(
                    new xmlrpcval($course_id, "string"),
                    new xmlrpcval('Stud.IP', "string"),
                    new xmlrpcval($tstamp, "string"),
                    new xmlrpcval($hash, "string")
                )
            );
        } else {
            $msg = new xmlrpcmsg(
                "info.course_status_v3", array(
                    new xmlrpcval($course_id, "string"),
                    new xmlrpcval('Stud.IP', "string"),
                    new xmlrpcval($tstamp, "string"),
                    new xmlrpcval($hash, "string"),
                    new xmlrpcval($user_id, 'string')
                )
            );
        }
        ob_start();
        $response = $this->client->send($msg, $this->timeout);
        $debug = ob_get_clean();
        if (!$response->faultCode()){
            $result = php_xmlrpc_decode($response->value());
        } else {
            error_log("UnizensusPlugin: An error occurred \n"
                    . "Code: ".$response->faultCode()." \n"
                    . "Reason: ".$response->faultString()." \n"
                    . "course_id:$course_id user_id:$user_id \n"
                    . $debug);

        }
        $old_data = $this->getResultFromCache($id, true);
        $last_changed = $old_data['last_changed'];
        unset($old_data['last_changed']);
        if(serialize($old_data) != serialize($result)){
            $result['last_changed'] = time();
        } else {
            $result['last_changed'] = $last_changed;
        }
        $this->putResultToCache($id, $result);
        return $result;
    }

    function getEvaluationURL($target, $course_id, $user_id){
        $tstamp = date('Y-m-d-H-i', time() + 120);
        $hash = md5($course_id . Config::get()->UNIZENSUSPLUGIN_SHARED_SECRET1 . $tstamp . Config::get()->UNIZENSUSPLUGIN_SHARED_SECRET2 . $user_id . $target);
        //$hash = hash_hmac('md5', $course_id.$course_id.$target.$tstamp.$user_id, Config::get()->UNIZENSUSPLUGIN_SHARED_SECRET1 . Config::get()->UNIZENSUSPLUGIN_SHARED_SECRET2);
        $url = Config::get()->UNIZENSUSPLUGIN_URL_PREFIX . 'app?service=pex/StudIpLoginPage';
        $url .= "&sp=$tstamp&sp=$hash&sp=$user_id&sp=$target&sp=".$course_id."&sp=$course_id";
        return $url;
    }

    function putResultToCache($id, $result){
        if ($this->cache){
            $db = new DB_Seminar();
            $data = addslashes(serialize($result));
            $db->query("REPLACE INTO unizensusplugincache (id,data,chdate) VALUES ('$id', '$data', UNIX_TIMESTAMP())");
            return $db->affected_rows();
        }
    }

    function getResultFromCache($id, $override = false){
        $result = null;
        if ($this->cache){
            $db = new DB_Seminar();
            $db->query("SELECT data FROM unizensusplugincache WHERE id='$id'" . (!$override ? " AND chdate > " . (time() - $this->cache) : ""));
            if ($db->next_record()){
                $result = unserialize($db->f('data'));
            }
        }
        return $result;
    }
}