请求支付宝二维码图片内容很慢的解决办法

最近开发支付宝小程序项目，通过接口生成的二维码打算下载到服务器，用file_get_contents 获取，结果被限制了很慢7-10秒才获取到

用img 标签访问也是很快，估计是判断了浏览器请求头

后来网上找到解决办法，用curl 模拟浏览器进行访问。秒取

<?php
$camera_url = 'https://mdgw.alipay.com/wsdk/img?fileid=A*OG3WRZIq5S0AAAAAAAAAAAAAAQAAAQ&bz=am_afts_openhome&zoom=original';
$camera_base64 = get_head($camera_url);
if ($camera_base64!='') {
    echo json_encode(array('camera_base64' => $camera_base64),JSON_UNESCAPED_UNICODE);;
}
function get_head($url)
{
    $header = [
        'User-Agent: Mozilla/5.0 (Windows NT 6.1; Win64; x64; rv:45.0) Gecko/20100101 Firefox/45.0',
        'Accept-Language: zh-CN,zh;q=0.8,en-US;q=0.5,en;q=0.3',
        'Accept-Encoding: gzip, deflate',
    ];
    $curl = curl_init();
    curl_setopt($curl, CURLOPT_URL, $url);
    curl_setopt($curl, CURLOPT_RETURNTRANSFER, true);
    curl_setopt($curl, CURLOPT_FOLLOWLOCATION, true);
    curl_setopt($curl, CURLOPT_ENCODING, ‘gzip‘);
    curl_setopt($curl, CURLOPT_HTTPHEADER, $header);
    $data = curl_exec($curl);
    $code = curl_getinfo($curl, CURLINFO_HTTP_CODE);
    curl_close($curl);
    file_put_contents('aaa.png',$data);
    if ($code == 200) {//把URL格式的图片转成base64_encode格式的！
        $imgBase64Code = "data:image/jpeg;base64," . base64_encode($data);
        return $imgBase64Code;//图片内容
    } else {
        return '获取头像失败';
    }
}