How to implement WeChat refund application in PHP

I talked about how to implement WeChat payment earlier, please see related articles for details: The process of implementing WeChat payment (jsapi payment) in PHP and The process of implementing WeChat payment (jsapi payment) in ThinkPHP. Due to business needs, WeChat refund is also required. After research and exploration, it was finally solved.

Preliminary preparation:

Of course, WeChat payment has been settled, otherwise how can I get a refund? This time I will use the official demo. Of course, there may be many masters on the Internet who have rewritten and encapsulated the demo themselves, which may be easier to use and simpler, but I still don’t recommend using it for the following reasons:

(1) It may not be fully functional, maybe it just implements WeChat payment , but there are also business functions such as applying for refunds, querying refunds, order inquiries, and canceling orders, which you may need later. If you rely on the convenience of the master’s SDK, you will be confused if there are new business needs;

(2) Security considerations, when it comes to payment and money, it must be very safe. Although I also complain about the official SDK, at least it will be relatively safe. It will be rewritten again. Although no problems have been found for the time being, it will be bad if there are loopholes.

This article is still implemented by using the refund() method provided in WxPay.Api.php, the most important class file in the official SDK. This method is located at No. 141 of the WxPay.Api.php file. OK, the code is as follows:

/**
 * 
 * 申请退款，WxPayRefund中out_trade_no、transaction_id至少填一个且
 * out_refund_no、total_fee、refund_fee、op_user_id为必填参数
 * appid、mchid、spbill_create_ip、nonce_str不需要填入
 * @param WxPayRefund $inputObj
 * @param int $timeOut
 * @throws WxPayException
 * @return 成功时返回，其他抛异常
 */
public static function refund($inputObj, $timeOut = 6){
$url = "https://api.mch.weixin.qq.com/secapi/pay/refund";
//检测必填参数
if(!$inputObj->IsOut_trade_noSet() && !$inputObj->IsTransaction_idSet()) {
throw new WxPayException("退款申请接口中，out_trade_no、transaction_id至少填一个！");
}else if(!$inputObj->IsOut_refund_noSet()){
throw new WxPayException("退款申请接口中，缺少必填参数out_refund_no！");
}else if(!$inputObj->IsTotal_feeSet()){
throw new WxPayException("退款申请接口中，缺少必填参数total_fee！");
}else if(!$inputObj->IsRefund_feeSet()){
throw new WxPayException("退款申请接口中，缺少必填参数refund_fee！");
}else if(!$inputObj->IsOp_user_idSet()){
throw new WxPayException("退款申请接口中，缺少必填参数op_user_id！");
}
$inputObj->SetAppid(WxPayConfig::APPID);//公众账号ID
$inputObj->SetMch_id(WxPayConfig::MCHID);//商户号
$inputObj->SetNonce_str(self::getNonceStr());//随机字符串
$inputObj->SetSign();//签名
$xml = $inputObj->ToXml();
$startTimeStamp = self::getMillisecond();//请求开始时间
$response = self::postXmlCurl($xml, $url, true, $timeOut);
$result = WxPayResults::Init($response);
self::reportCostTime($url, $startTimeStamp, $result);//上报请求花费时间
return $result;
}

The official method clearly states which parameters are required, and the SDK has already filled in some required parameters for us. I will re-encapsulate this method to facilitate calling it in the project. :

/**
 * 微信退款
 * @param  string   $order_id 订单ID
 * @return 成功时返回(array类型)，其他抛异常
 */
function wxRefund($order_id){
//我的SDK放在项目根目录下的Api目录下
require_once APP_ROOT."/Api/wxpay/lib/WxPay.Api.php";
//查询订单,根据订单里边的数据进行退款
$order = M('order')->where(array('id'=>$order_id,'is_refund'=>2,'order_status'=>1))->find();
$merchid = WxPayConfig::MCHID;
if(!$order) return false;
$input = new WxPayRefund();
$input->SetOut_trade_no($order['order_sn']);//自己的订单号
$input->SetTransaction_id($order['transaction_id']);  //微信官方生成的订单流水号，在支付成功中有返回
$input->SetOut_refund_no(getrand_num(true));//退款单号
$input->SetTotal_fee($order['total_price']);//订单标价金额，单位为分
$input->SetRefund_fee($order['total_price']);//退款总金额，订单总金额，单位为分，只能为整数
$input->SetOp_user_id($merchid);
$result = WxPayApi::refund($input);//退款操作
// 这句file_put_contents是用来查看服务器返回的退款结果 测试完可以删除了
//file_put_contents(APP_ROOT.'/Api/wxpay/logs/log3.txt',arrayToXml($result),FILE_APPEND);
return $result;
}

I need to make a complaint here. The type of the return value is not mentioned. When paying, XML data is returned. However, an array is returned here, which caught me off guard. Haha, but it is better to return an array. Can be directly judged and processed.

The method call is even simpler:

//微信退款
$result = wxRefund($order_id);
// 这句file_put_contents是用来查看服务器返回的退款结果 测试完可以删除了
//file_put_contents(APP_ROOT.'/Api/wxpay/logs/log4.txt',arrayToXml($result),FILE_APPEND);
if(($result['return_code']=='SUCCESS') && ($result['result_code']=='SUCCESS')){
//退款成功
}else if(($result['return_code']=='FAIL') || ($result['result_code']=='FAIL')){
//退款失败
//原因
$reason = (empty($result['err_code_des'])?$result['return_msg']:$result['err_code_des']);
}else{
//失败
}

The refund is returned successfully as follows:

Personal test is correct: this is an integrated official Implemented by the SDK, if you do not use the SDK, you can use a simpler method, see: PHP to implement WeChat payment (jsapi payment) and refund (no need to integrate the payment SDK)

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