微信退款代码

<?php

    //退款方法-根据退款单号--纯原生，不依赖支付插件
    public static function wxAppRefund($refund_no)
        {
            $refund = OrderAftersales::where('refund_no',$refund_no)->find();
            
            if(empty($refund) || $refund['status'] != 1){
                throw new Exception("退款不存在或已处理");
            }
            $number = $refund['refund'];
            $orders = self::where('id',$refund['order_id'])->find();
            if(empty($orders)){
                throw new Exception("订单不存在");
            }
            if(($orders['orderstate'] != 4) && ($orders['paystate'] != 1) ){
                throw new Exception('订单状态有误');
            }
            $appid = ''; //微信appid
            $mch_key = '';//微信支付key
            $mch_id = '';//微信商户id
            $config = ['app_id' => $appid,'mch_id' => $mch_id,'mch_key' => $mch_key];
            if(!$config || !$config['mch_id'] || !$config['mch_key']){
                throw new Exception('请正确配置微信商户信息');
            }
    
            $appid = $config['app_id'];
            $mch_id = $config['mch_id'];
            $key = $config['mch_key'];
    
            // 修复证书路径 - 使用绝对路径
            $cert_path = ROOT_PATH . 'public/uploads/apppay/apiclient_cert.pem';
            $key_path = ROOT_PATH . 'public/uploads/apppay/apiclient_key.pem';
    
            // 检查证书文件是否存在
            if (!file_exists($cert_path)) {
                throw new Exception('证书文件不存在: ' . $cert_path);
            }
            if (!file_exists($key_path)) {
                throw new Exception('私钥文件不存在: ' . $key_path);
            }
    
            $order_no = $orders['order_sn'];
            $nonce_str = md5(uniqid(mt_rand(), true));
        $params = [
            'appid'         => $appid,
            'mch_id'        => $mch_id,
            'nonce_str'     => $nonce_str,
            'out_trade_no'  => $order_no,    // 原支付订单号
            'out_refund_no' => $refund_no,   // 退款单号，需唯一
            'total_fee'     => intval($orders['payamount'] * 100),   // 原订单金额（分）
            'refund_fee'    => intval($number * 100),  // 退款金额（分）
            'op_user_id'    => $mch_id, // 操作员，默认传商户号
            // 'notify_url' => 'https://your.domain/refund_notify', // 如需回调可配置
        ];

        // 生成签名（过滤空值）
        $signParams = array_filter($params, function($v){ return $v !== '' && $v !== null; });
        ksort($signParams);
        $string = urldecode(http_build_query($signParams)) . "&key={$key}";
        $params['sign'] = strtoupper(md5($string));
    
            // 转XML
            $xml = '<xml>';
            foreach ($params as $k => $v) {
                $xml .= "<{$k}>{$v}</{$k}>";
            }
            $xml .= '</xml>';
    
            // 请求微信退款API
            $url = 'https://api.mch.weixin.qq.com/secapi/pay/refund';
            $res = self::wx_ssl_post($url, $xml, $cert_path, $key_path);
    
        // 解析返回
        $result = simplexml_load_string($res, 'SimpleXMLElement', LIBXML_NOCDATA);
            if ($result->return_code == 'SUCCESS' && $result->result_code == 'SUCCESS') {
                // 退款成功，处理业务逻辑
                return true;
            } else {
                // 退款失败，记录详细错误信息
                $error_msg = '退款失败: ';
                if (isset($result->err_code)) {
                    $error_msg .= '错误码: ' . $result->err_code . ', ';
                }
                if (isset($result->err_code_des)) {
                    $error_msg .= '错误描述: ' . $result->err_code_des;
                }
                throw new Exception($error_msg);
            }
        }

    // 带证书的POST请求
    public static function wx_ssl_post($url, $data, $cert_path, $key_path)
    {
        $ch = curl_init();
        curl_setopt($ch, CURLOPT_TIMEOUT, 30);
        curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
        curl_setopt($ch, CURLOPT_URL, $url);
        curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, false);
        curl_setopt($ch, CURLOPT_SSL_VERIFYHOST, false);

        // 证书设置
        curl_setopt($ch, CURLOPT_SSLCERT, $cert_path);
        curl_setopt($ch, CURLOPT_SSLKEY, $key_path);
        curl_setopt($ch, CURLOPT_SSLCERTPASSWD, ''); // 证书密码，如果有的话
        curl_setopt($ch, CURLOPT_SSLKEYPASSWD, '');  // 私钥密码，如果有的话

        curl_setopt($ch, CURLOPT_POST, 1);
        curl_setopt($ch, CURLOPT_POSTFIELDS, $data);

        $res = curl_exec($ch);
        $error = curl_errno($ch);
        $error_msg = curl_error($ch);
        curl_close($ch);

        if ($res) {
            return $res;
        } else {
            throw new \Exception('微信退款接口请求失败，CURL错误码：' . $error . '，错误信息：' . $error_msg);
        }
    }