CONFIG_DOZMOD_EXPIRE) { return false; } else { return true; } } function cache_get($key) { $filename = cache_key_to_filename($key); return file_get_contents($filename); } /* good for large binary files */ function cache_get_passthru($key) { $filename = cache_key_to_filename($key); $fp = fopen($filename, "r"); if ($fp) { fpassthru($fp); exit; } error_log('Cannot passthrough cache file ' . $filename); } /* END: Cache ---------------------------------------------------- */ /* this script requires 2 (3 with implicit client ip) parameters * * resource = vmx,... * lecture_uuid = client can choose **/ /** * Takes raw lecture list xml, returns array of uuids. * * @param string $responseXML XML from dozmod server * @return array list of UUIDs, false on error */ function xmlToLectureIds($responseXML) { $xml = new SimpleXMLElement($responseXML); if (!isset($xml->eintrag)) return []; $uuids = []; foreach ($xml->eintrag as $e) { if (isset($e->uuid) && isset($e->uuid['param']) && isset($e->uuid['param'][0])) { $uuids[] = strval($e->uuid['param'][0]); } } return $uuids; } function sendExamModeMismatch() { Header('Content-Type: text/xml; charset=utf-8'); echo << BLA; exit(0); } /** Caching wrapper around _getLecturesForLocations() */ function getListForLocations($locationIds, $raw) { /* if in any of the locations there is an exam active, consider the client to be in "exam-mode" and only offer him exams (no lectures) */ $key = 'lectures_' . cache_hash($locationIds); $examMode = Request::get('exams', 'normal-mode', 'string') !== 'normal-mode'; $clientServerMismatch = false; if (Module::isAvailable('exams')) { // If we have the exam mode module, we can enforce a server side check and make sure it agrees with the client $serverExamMode = Exams::isInExamMode($locationIds); if ($raw) { $clientServerMismatch = ($serverExamMode !== $examMode); } $examMode = $serverExamMode; } // Only enforce exam mode validity check if the client requests the raw xml data if ($clientServerMismatch) { sendExamModeMismatch(); // does not return } // Proceed normally from here on if ($examMode) { $key .= '_exams'; } $rawKey = $key . '_raw'; if ($raw) { Header('Content-Type: text/xml; charset=utf-8'); if (cache_has($rawKey)) { cache_get_passthru($rawKey); } } elseif (cache_has($key)) { return unserialize(cache_get($key)); } // Not in cache $url = LIST_URL . "?locations=" . implode('%20', $locationIds); if ($examMode) { $url .= '&exams'; } $value = Download::asString($url, 60, $code); if ($value === false || $code < 200 || $code > 299) return false; cache_put($rawKey, $value); $list = xmlToLectureIds($value); cache_put($key, serialize($list)); if ($raw) { die($value); } return $list; } function getLectureUuidsForLocations($locationIds) { return getListForLocations($locationIds, false); } function outputLectureXmlForLocation($locationIds) { return getListForLocations($locationIds, true); } function _getVmData($lecture_uuid, $subResource = false) { $url = VMX_URL . '/' . $lecture_uuid; if ($subResource !== false) { $url .= '/' . $subResource; } $response = Download::asString($url, 60, $code); if ($code < 200 || $code > 299) return (int)$code; return $response; } /** Caching wrapper around _getVmData() **/ function outputResource($lecture_uuid, $resource) { if ($resource === 'metadata') { // HACK: config.tgz is compressed, don't use gzip output handler @ob_end_clean(); Header('Content-Type: application/gzip'); } else { Header('Content-Type: text/plain; charset=utf-8'); } $key = $resource . '_' . $lecture_uuid; if (cache_has($key)) { cache_get_passthru($key); } else { $value = _getVmData($lecture_uuid, $resource); if ($value === false) return false; if (is_int($value)) { http_response_code($value); exit; } cache_put($key, $value); die($value); } return false; } function fatalDozmodUnreachable() { Header('HTTP/1.1 504 Gateway Timeout'); die('DMSD currently not available'); } function readLectureParam($locationIds) { $lecture = Request::get('lecture', false, 'string'); if ($lecture === false) { Header('HTTP/1.1 400 Bad Request'); die('Missing lecture UUID'); } $lectures = getLectureUuidsForLocations($locationIds); if ($lectures === false) { fatalDozmodUnreachable(); } /* check that the user requests a lecture that he is allowed to have */ if (!in_array($lecture, $lectures)) { Header('HTTP/1.1 403 Forbidden'); die("You don't have permission to access this lecture"); } return $lecture; } // -----------------------------------------------------------------------------// /* request data, don't trust */ $resource = Request::get('resource', false, 'string'); if ($resource === false) { Util::traceError("you have to specify the 'resource' parameter"); } if (!in_array($resource, $availableRessources)) { Header('HTTP/1.1 400 Bad Request'); die("unknown resource: $resource"); } $ip = $_SERVER['REMOTE_ADDR']; if (substr($ip, 0, 7) === '::ffff:') { $ip = substr($ip, 7); } /* lookup location id(s) */ $location_ids = Location::getFromIp($ip, true); $location_ids = Location::getLocationRootChain($location_ids); if ($resource === 'list') { outputLectureXmlForLocation($location_ids); // Won't return on success... fatalDozmodUnreachable(); } else { $lecture = readLectureParam($location_ids); outputResource($lecture, $resource); fatalDozmodUnreachable(); } Header('HTTP/1.1 400 Bad Request'); die("I don't know how to give you that resource");