php实现微信支付之退款功能

网上的很多PHP微信支付接入教程都颇为复杂，且需要配置和引入较多的文件，本人通过整理后给出一个单文件版的，希望可以给各位想接入微信支付的带来些许帮助和借鉴意义。

直接运行该文件即可给指定的微信用户退款。

需要注意的事项：

1.微信退款到零钱要求必传证书，需要到这里账户中心->账户设置->API安全->下载证书，然后修改代码中的证书路径
2.该文件需放到支付授权目录下，可以在微信支付商户平台->产品中心->开发配置中设置。
3.如提示签名错误可以通过微信支付签名验证工具进行验证：微信公众平台支付接口调试工具
4.错误码参照：参照地址

代码如下：

<?php/** * 关于微信退款的说明 * 1.微信退款要求必传证书，需要到https://pay.weixin.qq.com 账户中心->账户设置->API安全->下载证书，证书路径在第119行和122行修改 * 2.错误码参照 ：https://pay.weixin.qq.com/wiki/doc/api/jsapi.php?chapter=9_4 */header('Content-type:text/html; Charset=utf-8');$mchid = 'xxxxx';     //微信支付商户号 PartnerID 通过微信支付商户资料审核后邮件发送$appid = 'xxxxx'; //微信支付申请对应的公众号的APPID$apiKey = 'xxxxx';  //https://pay.weixin.qq.com 帐户设置-安全设置-API安全-API密钥-设置API密钥$orderNo = '';           //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 = 0.01;          //订单金额，单位:元$refundFee = 0.01;         //退款金额，单位:元$refundNo = 'refund_'.uniqid();    //退款订单号(可随机生成)$wxPay = new WxpayService($mchid,$appid,$apiKey);$result = $wxPay->doRefund($totalFee, $refundFee, $refundNo, $wxOrderNo,$orderNo);if($result===true){  echo 'refund success';exit();}echo 'refund fail';class WxpayService{  protected $mchid;  protected $appid;  protected $apiKey;  public $data = null;  public function __construct($mchid, $appid, $key)  {    $this->mchid = $mchid; //https://pay.weixin.qq.com 产品中心-开发配置-商户号    $this->appid = $appid; //微信支付申请对应的公众号的APPID    $this->apiKey = $key;  //https://pay.weixin.qq.com 帐户设置-安全设置-API安全-API密钥-设置API密钥  }  /**   * 退款   * @param float $totalFee 订单金额 单位元   * @param float $refundFee 退款金额 单位元   * @param string $refundNo 退款单号   * @param string $wxOrderNo 微信订单号   * @param string $orderNo 商户订单号   * @return string   */  public function doRefund($totalFee, $refundFee, $refundNo, $wxOrderNo='',$orderNo='')  {    $config = array(      'mch_id' => $this->mchid,      'appid' => $this->appid,      'key' => $this->apiKey,    );    $unified = array(      'appid' => $config['appid'],      'mch_id' => $config['mch_id'],      'nonce_str' => self::createNonceStr(),      'total_fee' => intval($totalFee * 100),    //订单金额  单位 转为分      'refund_fee' => intval($refundFee * 100),    //退款金额 单位 转为分      'sign_type' => 'MD5',      //签名类型 支持HMAC-SHA256和MD5，默认为MD5      'transaction_id'=>$wxOrderNo,        //微信订单号      'out_trade_no'=>$orderNo,    //商户订单号      'out_refund_no'=>$refundNo,    //商户退款单号      'refund_desc'=>'商品已售完',   //退款原因（选填）    );    $unified['sign'] = self::getSign($unified, $config['key']);    $responseXml = $this->curlPost('https://api.mch.weixin.qq.com/secapi/pay/refund', self::arrayToXml($unified));    $unifiedOrder = simplexml_load_string($responseXml, 'SimpleXMLElement', LIBXML_NOCDATA);    if ($unifiedOrder === false) {      die('parse xml error');    }    if ($unifiedOrder->return_code != 'SUCCESS') {      die($unifiedOrder->return_msg);    }    if ($unifiedOrder->result_code != 'SUCCESS') {      die($unifiedOrder->err_code);    }    return true;  }  public static function curlGet($url = '', $options = array())  {    $ch = curl_init($url);    curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);    curl_setopt($ch, CURLOPT_TIMEOUT, 30);    if (!empty($options)) {      curl_setopt_array($ch, $options);    }    //https请求 不验证证书和host    curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, false);    curl_setopt($ch, CURLOPT_SSL_VERIFYHOST, false);    $data = curl_exec($ch);    curl_close($ch);    return $data;  }  public function curlPost($url = '', $postData = '', $options = array())  {    if (is_array($postData)) {      $postData = http_build_query($postData);    }    $ch = curl_init();    curl_setopt($ch, CURLOPT_URL, $url);    curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);    curl_setopt($ch, CURLOPT_POST, 1);    curl_setopt($ch, CURLOPT_POSTFIELDS, $postData);    curl_setopt($ch, CURLOPT_TIMEOUT, 30); //设置cURL允许执行的最长秒数    if (!empty($options)) {      curl_setopt_array($ch, $options);    }    //https请求 不验证证书和host    curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, false);    curl_setopt($ch, CURLOPT_SSL_VERIFYHOST, false);    //第一种方法，cert 与 key 分别属于两个.pem文件    //默认格式为PEM，可以注释    curl_setopt($ch,CURLOPT_SSLCERTTYPE,'PEM');    curl_setopt($ch,CURLOPT_SSLCERT,getcwd().'/cert/apiclient_cert.pem');    //默认格式为PEM，可以注释    curl_setopt($ch,CURLOPT_SSLKEYTYPE,'PEM');    curl_setopt($ch,CURLOPT_SSLKEY,getcwd().'/cert/apiclient_key.pem');    //第二种方式，两个文件合成一个.pem文件//    curl_setopt($ch,CURLOPT_SSLCERT,getcwd().'/all.pem');    $data = curl_exec($ch);    curl_close($ch);    return $data;  }  public static function createNonceStr($length = 16)  {    $chars = 'abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789';    $str = '';    for ($i = 0; $i < $length; $i++) {      $str .= substr($chars, mt_rand(0, strlen($chars) - 1), 1);    }    return $str;  }  public static function arrayToXml($arr)  {    $xml = "<xml>";    foreach ($arr as $key => $val) {      if (is_numeric($val)) {        $xml .= "<" . $key . ">" . $val . "</" . $key . ">";      } else        $xml .= "<" . $key . "><![CDATA[" . $val . "]]></" . $key . ">";    }    $xml .= "</xml>";    return $xml;  }  public static function getSign($params, $key)  {    ksort($params, SORT_STRING);    $unSignParaString = self::formatQueryParaMap($params, false);    $signStr = strtoupper(md5($unSignParaString . "&key=" . $key));    return $signStr;  }  protected static function formatQueryParaMap($paraMap, $urlEncode = false)  {    $buff = "";    ksort($paraMap);    foreach ($paraMap as $k => $v) {      if (null != $v && "null" != $v) {        if ($urlEncode) {          $v = urlencode($v);        }        $buff .= $k . "=" . $v . "&";      }    }    $reqPar = '';    if (strlen($buff) > 0) {      $reqPar = substr($buff, 0, strlen($buff) - 1);    }    return $reqPar;  }}?>