php的curl携带header请求头信息实现http访问

 导读：

curl请求时添加请求头信息可以模拟真人操作，不容易被当成是爬虫机器人（采集），从而可以绕过Incapsula等安全验证机制。

1、首先使用浏览器（示例使用的是火狐浏览器）访问接口网址，使用F12调试，查看请求头信息，如下：

2、实现代码：

<?php
/**
* 开始访问请求
* @param $url
* @return bool|string
*/
function fetch_url($url) {
$header = FormatHeader($url);
$useragent = 'Mozilla/5.0 (Windows NT 6.1; Win64; x64; rv:83.0) Gecko/20100101 Firefox/83.0';
$timeout= 120;
$ch = curl_init($url);
curl_setopt($ch, CURLOPT_FAILONERROR, true);
//设置请求头信息
curl_setopt($ch, CURLOPT_HTTPHEADER, $header);
//不取得返回头信息
curl_setopt($ch, CURLOPT_HEADER, 0);
// 关闭https验证
curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, false);
curl_setopt($ch, CURLOPT_SSL_VERIFYHOST, false);
curl_setopt($ch, CURLOPT_FOLLOWLOCATION, true );
curl_setopt($ch, CURLOPT_ENCODING, "" );
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true );
curl_setopt($ch, CURLOPT_AUTOREFERER, true );
curl_setopt($ch, CURLOPT_CONNECTTIMEOUT, $timeout );
curl_setopt($ch, CURLOPT_TIMEOUT, $timeout );
curl_setopt($ch, CURLOPT_MAXREDIRS, 10 );
curl_setopt($ch, CURLOPT_USERAGENT, $useragent);
$content = curl_exec($ch);
if(curl_errno($ch))
{
echo 'Error:' . curl_error($ch);
}
else
{
return $content;
}
curl_close($ch);
}

//添加请求头
function FormatHeader($url)
{
// 解析url
$temp = parse_url($url);
$query = isset($temp['query']) ? $temp['query'] : '';
$path = isset($temp['path']) ? $temp['path'] : '/';
$header = array (
"POST {$path}?{$query} HTTP/1.1",
"Host: {$temp['host']}",
"Referer: http://{$temp['host']}/",
"Content-Type: text/xml; charset=utf-8",
'Accept: application/json, text/javascript, */*; q=0.01',
'Accept-Encoding:gzip, deflate, br',
'Accept-Language:zh-CN,zh;q=0.8,zh-TW;q=0.7,zh-HK;q=0.5,en-US;q=0.3,en;q=0.2',
'Connection:keep-alive',
'User-Agent: Mozilla/5.0 (Windows NT 6.1; Win64; x64; rv:83.0) Gecko/20100101 Firefox/83.0',
'X-Requested-With: XMLHttpRequest',
);
return $header;
}
?>

3、调用示例：

<?php
//lcg_value() 返回范围为 (0, 1) 的一个伪随机数
$url="http://www.xxx.com/getdata.php?v=".lcg_value();
//访问网址
$html = fetch_url($url);