include 'WeixinPay.php';
$appid=''; //小程序appid
$openid= $_POST['id'];
$mch_id=''; //微信支付商戶支付號
$key=''; //Api密鑰
$out_trade_no = $mch_id. time();
$total_fee = $_POST['fee'];
if (empty($total_fee)) { //押金
  $body = "充值押金";
  $total_fee = floatval(99*100);
} else {
   $body = "充值余額";
   $total_fee = floatval($total_fee*100);
 }
$weixinpay = new WeixinPay($appid,$openid,$mch_id,$key,$out_trade_no,$body,$total_fee);
$return=$weixinpay->pay();
echo json_encode($return);

/*
 * 小程序微信支付
 */
class WeixinPay {
  protected $appid;
  protected $mch_id;
  protected $key;
  protected $openid;
  protected $out_trade_no;
  protected $body;
  protected $total_fee;
  function __construct($appid, $openid, $mch_id, $key,$out_trade_no,$body,$total_fee) {
    $this->appid = $appid;
    $this->openid = $openid;
    $this->mch_id = $mch_id;
    $this->key = $key;
    $this->out_trade_no = $out_trade_no;
    $this->body = $body;
    $this->total_fee = $total_fee;
  }
  public function pay() {
    //統一下單接口
    $return = $this->weixinapp();
    return $return;
  }
  //統一下單接口
  private function unifiedorder() {
    $url = 'https://api.mch.weixin.qq.com/pay/unifiedorder';
    $parameters = array(
      'appid' => $this->appid, //小程序ID
      'mch_id' => $this->mch_id, //商戶號
      'nonce_str' => $this->createNoncestr(), //隨機字符串
//      'body' => 'test', //商品描述
      'body' => $this->body,
//      'out_trade_no' => '2018013106125348', //商戶訂單號
      'out_trade_no'=> $this->out_trade_no,
//      'total_fee' => floatval(0.01 * 100), //總金額 單位 分
      'total_fee' => $this->total_fee,
      'spbill_create_ip' => $_SERVER['REMOTE_ADDR'], //終端IP
      // 'spbill_create_ip' => '192.168.0.161', //終端IP
      'notify_url' => 'https://www.weixin.qq.com/wxpay/notify.php', //通知地址 確保外網能正常訪問
      'openid' => $this->openid, //用戶id
      'trade_type' => 'JSAPI'//交易類型
    );
    //統一下單簽名
    $parameters['sign'] = $this->getSign($parameters);
    $xmlData = $this->arrayToXml($parameters);
    $return = $this->xmlToArray($this->postXmlCurl($xmlData, $url, 60));
    return $return;
  }
  private static function postXmlCurl($xml, $url, $second = 30) 
  {
    $ch = curl_init();
    //設置超時
    curl_setopt($ch, CURLOPT_TIMEOUT, $second);
    curl_setopt($ch, CURLOPT_URL, $url);
    curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, FALSE);
    curl_setopt($ch, CURLOPT_SSL_VERIFYHOST, FALSE); //嚴格校驗
    //設置header
    curl_setopt($ch, CURLOPT_HEADER, FALSE);
    //要求結果為字符串且輸出到屏幕上
    curl_setopt($ch, CURLOPT_RETURNTRANSFER, TRUE);
    //post提交方式
    curl_setopt($ch, CURLOPT_POST, TRUE);
    curl_setopt($ch, CURLOPT_POSTFIELDS, $xml);
    curl_setopt($ch, CURLOPT_CONNECTTIMEOUT, 20);
    curl_setopt($ch, CURLOPT_TIMEOUT, 40);
    set_time_limit(0);
    //運行curl
    $data = curl_exec($ch);
    //返回結果
    if ($data) {
      curl_close($ch);
      return $data;
    } else {
      $error = curl_errno($ch);
      curl_close($ch);
      throw new WxPayException("curl出錯，錯誤碼:$error");
    }
  }
  //數組轉換成xml
  private function arrayToXml($arr) {
    $xml = "xml>";
    foreach ($arr as $key => $val) {
      if (is_array($val)) {
        $xml .= "" . $key . ">" . arrayToXml($val) . "/" . $key . ">";
      } else {
        $xml .= "" . $key . ">" . $val . "/" . $key . ">";
      }
    }
    $xml .= "/xml>";
    return $xml;
  }
  //xml轉換成數組
  private function xmlToArray($xml) {
    //禁止引用外部xml實體 
    libxml_disable_entity_loader(true);
    $xmlstring = simplexml_load_string($xml, 'SimpleXMLElement', LIBXML_NOCDATA);
    $val = json_decode(json_encode($xmlstring), true);
    return $val;
  }
  //微信小程序接口
  private function weixinapp() {
    //統一下單接口
    $unifiedorder = $this->unifiedorder();
//    print_r($unifiedorder);
    $parameters = array(
      'appId' => $this->appid, //小程序ID
      'timeStamp' => '' . time() . '', //時間戳
      'nonceStr' => $this->createNoncestr(), //隨機串
      'package' => 'prepay_id=' . $unifiedorder['prepay_id'], //數據包
      'signType' => 'MD5'//簽名方式
    );
    //簽名
    $parameters['paySign'] = $this->getSign($parameters);
    return $parameters;
  }
  //作用：產生隨機字符串，不長于32位
  private function createNoncestr($length = 32) {
    $chars = "abcdefghijklmnopqrstuvwxyz0123456789";
    $str = "";
    for ($i = 0; $i  $length; $i++) { $str .= substr($chars, mt_rand(0, strlen($chars) - 1), 1); } return $str; } //作用：生成簽名 private function getSign($Obj) { foreach ($Obj as $k => $v) {
      $Parameters[$k] = $v;
    }
    //簽名步驟一：按字典序排序參數
    ksort($Parameters);
    $String = $this->formatBizQueryParaMap($Parameters, false);
    //簽名步驟二：在string后加入KEY
    $String = $String . "key=" . $this->key;
    //簽名步驟三：MD5加密
    $String = md5($String);
    //簽名步驟四：所有字符轉為大寫
    $result_ = strtoupper($String);
    return $result_;
  }
  ///作用：格式化參數，簽名過程需要使用
  private function formatBizQueryParaMap($paraMap, $urlencode) {
    $buff = "";
    ksort($paraMap);
    foreach ($paraMap as $k => $v) {
      if ($urlencode) {
        $v = urlencode($v);
      }
      $buff .= $k . "=" . $v . "";
    }
    $reqPar = '';
    if (strlen($buff) > 0) {
      $reqPar = substr($buff, 0, strlen($buff) - 1);
    }
    return $reqPar;
  }
}

wx.request({
   url: 'https://yourhost.com/wxpay/payfee.php',//改成你自己的鏈接
   data:{
    id: app.globalData.openid,//獲取用戶openid
    fee:100 //商品價格
   },
   header: {
    'Content-Type': 'application/x-www-form-urlencoded'
   },
   method: 'POST',
   success: function (res) {
    console.log(res.data);
    console.log('調起支付');
    wx.requestPayment({
     'timeStamp': res.data.timeStamp,
     'nonceStr': res.data.nonceStr,
     'package': res.data.package,
     'signType': 'MD5',
     'paySign': res.data.paySign,
     'success': function (res) {
      console.log('success');
      wx.showToast({
       title: '支付成功',
       icon: 'success',
       duration: 3000
      });
     },
     'fail': function (res) {
      console.log(res);
     },
     'complete': function (res) {
      console.log('complete');
     }
    });
   },
   fail: function (res) {
    console.log(res.data)
   }
  });

$postXml = $GLOBALS["HTTP_RAW_POST_DATA"]; //接收微信參數 
// 接受不到參數可以使用file_get_contents("php://input"); PHP高版本中$GLOBALS好像已經被廢棄了
if (empty($postXml)) {
  return false;
}
 
//將xml格式轉換成數組
function xmlToArray($xml) {
  //禁止引用外部xml實體 
  libxml_disable_entity_loader(true);
  $xmlstring = simplexml_load_string($xml, 'SimpleXMLElement', LIBXML_NOCDATA);
  $val = json_decode(json_encode($xmlstring), true);
  return $val;
}

$attr = xmlToArray($postXml);
$total_fee = $attr['total_fee'];
$open_id = $attr['openid'];
$out_trade_no = $attr['out_trade_no'];
$time = $attr['time_end'];