PHP实现微信根据订单退款

$_config = require('config.php');
$mchid = $_config; //微信支付商户号 PartnerID 通过微信支付商户资料审核后邮件发送
$appid = $_config; //微信支付申请对应的公众号或小程序APPID
$apiKey = $_config; //https://pay.weixin.qq.com 帐户设置-安全设置-API安全-API密钥-设置API密钥
$orderNo = $order; //商户订单号(商户订单号与微信订单号二选一，至少填一个)
$wxOrderNo = ''; //微信订单号(商户订单号与微信订单号二选一，至少填一个)
$totalFee = number_format($order/100,2); //订单金额，单位:元
$refundFee = number_format($order/100,2); //退款金额，单位:元
$refundNo = date("YmdHis").rand(100000,999999); //退款订单号(可随机生成)
$wxPay = new WxpayService($mchid,$appid,$apiKey);

$result = $wxPay->doRefund($totalFee, $refundFee, $refundNo, $wxOrderNo,$orderNo);