Detailed explanation of PHP development to implement WeChat refund function

WeChat development is very popular now. This article describes the example of PHP development to implement the WeChat refund function. Sharing it with everyone for your reference, I hope it can help everyone.

details as follows:

Recently, I was adjusting the WeChat refund interface and found that there are many pitfalls. I would like to share with you

① If during the test, the web page prompts curl 58, it means there is a problem with the path of the certificate (the physical path must be filled in here, which is the absolute path)
② The web page prompts curl 52, which means that your certificate is not introduced enough. On the official demo There are only two certificates apiclient_cert.pem and apiclient_key.pem. You also need to introduce a certificate rootca.pem. This certificate requires you to log in to
your merchant platform to download
③ If the web page prompts "HTTP/1.1 200 OK Server : nginx Date: Tue, 20 Jun 2017 08:08:01 GMT Content-Type: text/plain Content-Length: 852 Connection: keep-alive Keep-Alive: timeout=8
means there is no problem with your code. It should be that the parameters are wrong. My previous mistake was to write out_refund_no and out_trade_no the same. It is also written this way on the WeChat official website, but there is a problem. , I modified out_refund_no and found that it works

Note: The unit of amount is cent

The following is the interface I wrote

function Home_index() {
  date_default_timezone_set("Asia/Shanghai");
  $date = date("YmdHis");
  $appid = "";
  $mch_id = "";
  $out_trade_no = "14487658021497944120";
  $op_user_id = "";
  $out_refund_no = $date;
  $total_fee = "500";
  $refund_fee = "500";
//  $transaction_id = "4009542001201706206596667604";
  $key = "";
  $nonce_str = nonceStr();
  $ref = strtoupper(md5("appid=$appid&mch_id=$mch_id&nonce_str=$nonce_str&op_user_id=$op_user_id"
          . "&out_refund_no=$out_refund_no&out_trade_no=$out_trade_no&refund_fee=$refund_fee&total_fee=$total_fee"
          . "&key=$key")); //sign加密MD5
  $refund = array(
  'appid' =>$appid, //应用ID，固定
  'mch_id' => $mch_id, //商户号，固定
  'nonce_str' => $nonce_str, //随机字符串
  'op_user_id' => $op_user_id, //操作员
  'out_refund_no' => $out_refund_no, //商户内部唯一退款单号
  'out_trade_no' => $out_trade_no, //商户订单号,pay_sn码 1.1二选一,微信生成的订单号，在支付通知中有返回
  // 'transaction_id'=>'1',//微信订单号 1.2二选一,商户侧传给微信的订单号
  'refund_fee' => $refund_fee, //退款金额
  'total_fee' => $total_fee, //总金额
  'sign' => $ref//签名
  );
  $url = "https://api.mch.weixin.qq.com/secapi/pay/refund";
  ; //微信退款地址，post请求
  $xml = arrayToXml($refund);
  $ch = curl_init();
  curl_setopt($ch, CURLOPT_URL, $url);
  curl_setopt($ch, CURLOPT_HEADER, 1);
  curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
  curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, 1); //证书检查
  if ($useCert == true) {
    // 设置证书
    curl_setopt($ch, CURLOPT_SSLCERTTYPE, 'pem');
    curl_setopt($ch, CURLOPT_SSLCERT, dirname(__FILE__) . '/WxPay/cert/apiclient_cert.pem');
    curl_setopt($ch, CURLOPT_SSLCERTTYPE, 'pem');
    curl_setopt($ch, CURLOPT_SSLKEY, dirname(__FILE__) . '/WxPay/cert/apiclient_key.pem');
    curl_setopt($ch, CURLOPT_SSLCERTTYPE, 'pem');
    curl_setopt($ch, CURLOPT_CAINFO, dirname(__FILE__) . '/WxPay/cert/rootca.pem');
  }
  curl_setopt($ch, CURLOPT_POST, 1);
  curl_setopt($ch, CURLOPT_POSTFIELDS, $xml);
  $xml = curl_exec($ch);
  // 返回结果0的时候能只能表明程序是正常返回不一定说明退款成功而已
  if ($xml) {
    curl_close($ch);
    // 把xml转化成数组
    libxml_disable_entity_loader(true);
    $xmlstring = simplexml_load_string($xml, 'SimpleXMLElement', LIBXML_NOCDATA);
//    var_dump($xmlstring);
    $result['errNum'] = 0;
    $result['info'] = object_to_array($xmlstring);
//    var_dump($result);
    return $result;
  } else {
    $error = curl_errno($ch);
    curl_close($ch);
    // 错误的时候返回错误码。
    $result['errNum'] = $error;
    return $result;
  }
}
function arrayToXml($arr) {
  $xml = "<root>";
  foreach ($arr as $key => $val) {
    if (is_array($val)) {
      $xml .= "<" . $key . ">" . arrayToXml($val) . "</" . $key . ">";
    } else {
      $xml .= "<" . $key . ">" . $val . "</" . $key . ">";
    }
  }
  $xml .= "</root>";
  return $xml;
}
function object_to_array($obj) {
  $obj = (array) $obj;
  foreach ($obj as $k => $v) {
    if (gettype($v) == &#39;resource&#39;) {
      return;
    }
    if (gettype($v) == &#39;object&#39; || gettype($v) == &#39;array&#39;) {
      $obj[$k] = (array) object_to_array($v);
    }
  }
  return $obj;
}
function nonceStr() {
  $chars = "abcdefghijklmnopqrstuvwxyz0123456789";
  $str = "";
  $length = 32;
  for ($i = 0; $i < $length; $i++) {
    $str .= substr($chars, mt_rand(0, strlen($chars) - 1), 1);
  }
  // 随机字符串
  return $str;
}
Home_index();

Have you learned it? Please add it to your project as soon as possible.

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