微信内调起H5支付，微信公众号调起H5支付

应该用公众号支付里的公众 号内H5支付

    public function  h5_pay($pay_sn){
         header("Content-Type: text/html;charset=utf-8");
            $param['appId'] = $this->payment_config['wxpay']['payment_config']['wxpay_appid'];
            $param['timeStamp'] =strval(time());
            $param['nonceStr'] = md5(rand());
            $prepay_id = $this->_get_wx_pay($pay_sn,'wxpay');   //统一下单 
            $param['package'] ="prepay_id=".$prepay_id;      //统一下单生成的
            $param['signType'] ="MD5";
            $paySign =   $this->_get_wx_pay_sign3($param,'wxpay');   //签名
            $param['paySign'] =$paySign;
         
            return $param;
    }

   //统一下单
    public function _get_wx_pay($pay_sn,$payment_code) {
         $openid =  Model()->table('member')->field('openid')->where(array('member_id'=>$_SESSION['userid']))->find()['openid'];
         if(!$openid){
               $openid =$_COOKIE['openid'];
         }
        $noncestr = md5(rand());
        $param = array();
         $param['appid'] = $this->payment_config['wxpay']['payment_config']['wxpay_appid'];
         $param['mch_id'] = $this->payment_config['wxpay']['payment_config']['wxpay_partnerid'];
         $param['openid'] = $openid;
        $param['nonce_str'] = $noncestr;
        $param['body'] = '微信-H5支付';
        $param['out_trade_no'] = $pay_sn;
        $param['total_fee'] = 1;
        $param['spbill_create_ip'] = get_server_ip();    //用户ip
        $param['notify_url'] =  BASE_SITE_URL . '/app/api/payment/wxpay_app/notify_url_order.php';
        $param['trade_type'] = 'JSAPI';    


        $sign = $this->_get_wx_pay_sign3($param,'wxpay');
        //var_dump($sign);exit;
        $param['sign'] = $sign;
        //var_dump($sign);exit;
        
        $post_data =$this->arrayToXml($param);
        //var_dump($post_data);exit;
        $prepay_result = http_postdata('https://api.mch.weixin.qq.com/pay/unifiedorder', $post_data);
        $result =  $this->xmlToArray($prepay_result);

   
        return $result['prepay_id'];
    }

    private function _get_wx_pay_sign3($param,$payment_code) {   //生成签名
        ksort($param);
        foreach ($param as $key => $val) {
            $string .= $key . '=' . $val . '&';
        }
        $string .= 'key=' . $this->payment_config[$payment_code]['payment_config']['wxpay_partnerkey'];
        return strtoupper(md5($string));
    }
           //xml转换成数组
   private function xmlToArray($xml) {
      //禁止引用外部xml实体
      libxml_disable_entity_loader(true);
      $xmlstring = simplexml_load_string($xml, 'SimpleXMLElement', LIBXML_NOCDATA);
      $val = json_decode(json_encode($xmlstring), true);
      return $val;
   }   


 //数组转换成xml
      private 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;
      }