微信小程序后端生成二维码

public function getQcode($id=null)
    {
        $access_token=db('Ztoken')->where('id',1)->find()['token'];
        $url='https://api.weixin.qq.com/cgi-bin/wxaapp/createwxaqrcode?access_token='.$access_token;
        $data=json_encode(['path'=>'pages/index/newsinfo/newsinfo?id='.$id,'width'=> 150]);
        $res=$this->httpPost($url,$data);
        $result=json_decode($res,true);
        if(isset($result['errcode'])&&($result['errcode']=='42001'||$result['errcode']=='40001')){
            $this->getAc();
            $this->getQcode();
        }else if(!isset($result['errcode'])){
            $path = '/uploads/qrcode/wenzhang'.time().$id.'.jpg';
            $re=file_put_contents(ROOT_PATH . '/public'.$path, $res);//保存图片
            $img='https://domain/' . $path;
            return $img;
             //echo '<img src='.$img.'>';
            //$base64_image ="data:image/jpeg;base64,".base64_encode( $res );//base64
            //return '<img src='.$base64_image.'>';
        }else{
            return '';
        }
        
        
    }