微信app支付

<code>function wechat($appid,$mchid,$appkey,$cert_path,$key_path,$order_id,$openid,$amount,$desc){
    $arr = [
            'mch_appid'=>$appid,//注意区分公众号和app商户号不同
            'mchid'=>$mchid,
            'nonce_str'=>str_random(32),//随机数
            'partner_trade_no'=>$order_id,//自己定义一个不重复订单号
            'openid'=>$openid,//微信openid 通过微信授权登录获取
            'check_name'=>'NO_CHECK',
            'amount'=>$amount*100,//注意这里传给微信的单位是分
            'desc'=>$desc,
            'spbill_create_ip'=>\Request::getClientIp(),
            'sign'=>'',
        ];
        ksort($arr);
        $sign="";
        foreach ($arr as $key => $value) {
            if($value && $key!="sign" && $key!="key"){
                $sign.=$key."=".$value."&";
            }
        }
        $sign.="key=".$appkey;//商户后台自定义的
        $arr['sign'] = strtoupper(md5($sign));
        $xml = "<xml>";
        foreach ($arr as $key=>$val)
        {
                if (is_numeric($val))
             {
                $xml.="<".$key.">".$val."</".$key.">"; 

             }
             else
                $xml.="<".$key."><![CDATA[".$val."]]></".$key.">";  
        }
        $xml.="</xml>";
       
        $ch = curl_init();
        //超时时间
        curl_setopt($ch,CURLOPT_TIMEOUT,60);
        curl_setopt($ch,CURLOPT_URL,'https://api.mch.weixin.qq.com/mmpaymkttransfers/promotion/transfers');
        curl_setopt($ch,CURLOPT_SSL_VERIFYPEER,false);
        curl_setopt($ch,CURLOPT_SSL_VERIFYHOST,false);
        //默认格式为PEM
        curl_setopt($ch,CURLOPT_SSLCERTTYPE,'PEM');
        curl_setopt($ch,CURLOPT_SSLCERT,$cert_path);//注意区分公众号和app商户号的证书不同，需要到pay.weixin.qq.com后台下载
        curl_setopt($ch,CURLOPT_SSLKEYTYPE,'PEM');
        curl_setopt($ch,CURLOPT_SSLKEY,$key_path);
        curl_setopt($ch,CURLOPT_RETURNTRANSFER, 1);
        curl_setopt($ch, CURLOPT_HTTPHEADER, array('Content-Type: text/xml'));
        curl_setopt($ch,CURLOPT_POST, 1);
        curl_setopt($ch,CURLOPT_POSTFIELDS,$xml);
        $data = curl_exec($ch);
        $data = json_decode(json_encode(simplexml_load_string($data, 'SimpleXMLElement', LIBXML_NOCDATA)), true);
        curl_close($ch);
        return $data;//$data['return_code'] == 'SUCCESS' && $data['result_code'] == 'SUCCESS' 支付成功
    }
    }</code>