php菜鸟求教,下面这个php方法表示什么意思?看不懂

php菜鸟求教,下面这个php方法表示什么意思?看不懂public function responseMsg() {//get post data, May be due to the different environments$postStr = $GLOBALS["HTTP_RAW_POST_DATA"]; //extract post dataif (!empty($postStr)){ $postObj = simplexml_load_string($postStr, 'SimpleXMLElement', LIBXML_NOCDATA); $fromUsername = $postObj->FromUserName; $toUsername = $postObj->ToUserName; $keyword = trim($postObj->Content); $time = time(); $textTpl = "%s0"; if(!empty( $keyword )) { $msgType = "text"; $contentStr = "Welcome to wechat world!"; $resultStr = sprintf($textTpl, $fromUsername, $toUsername, $time, $msgType, $contentStr); echo $resultStr; }else{ echo "Input something..."; } }else { echo ""; exit; } }