CURL 用户代理 [英] The CURL User Agent

问题描述

那么如何使用 codeigniter 检查客户端是否为 curl，然后为其返回不同的内容?

解决方案

你可以在使用 cURL 时伪造用户代理，所以当你知道它是一个卷曲请求.

例如:我最近编写了一个应用程序，它可以从谷歌获取一个 url 的 pagerank.现在谷歌不喜欢这个，所以它只允许某个用户代理访问它的pagerank服务器.解决方案?使用 cURL 欺骗用户代理，Google 也不会更聪明.

故事的寓意:cURL 用户代理并不可靠.

如果你还想这样做，那么你应该能够像往常一样获得通过的用户代理

$userAgent=$_SERVER['HTTP_USER_AGENT'];

编辑一个快速测试证明了这一点:

dumpx.php:

dump.php:

案例 1:http://localhost/dumpx.php?u=y

 'HTTP_USER_AGENT' =>字符串嘘！"(长度=7)

案例 2:http://localhost/dumpx.php?u=n

没有 $_SERVER['HTTP_USER_AGENT']

这证明 curl 没有默认的用户代理:它只是不会在请求头中传递它

So how can I check using codeigniter if the client is curl, and then return something different for it?

解决方案

You can fake the user-agent when using cURL, so it's pointless depending on the user-agent sent when you KNOW it's a cURL request.

For example: I recently wrote an app which gets the pagerank of a url from google. Now Google doesn't like this, so it allows only a certain user agent to access its pagerank servers. Solution? Spoof the user-agent using cURL and Google will be none the wiser.

Moral of the story: cURL user agents are JUST NOT reliable.

If you still want to do this, then you should be able to get the passed user agent just like normal

$userAgent=$_SERVER['HTTP_USER_AGENT'];

EDIT A quick test proved this:

dumpx.php:

<?php

    $url="http://localhost/dump.php";

    $ch = curl_init();
    curl_setopt($ch, CURLOPT_URL,$url);
    curl_setopt($ch, CURLOPT_FOLLOWLOCATION, 1);
    if($_GET['u']==y) {  
    curl_setopt($ch, CURLOPT_USERAGENT, "booyah!");
    }
    curl_setopt($ch, CURLOPT_RETURNTRANSFER, 0);

    curl_setopt($ch, CURLOPT_CONNECTTIMEOUT, 2);
    curl_setopt($ch, CURLOPT_TIMEOUT, 60);
    //curl_setopt($ch, CURLOPT_CUSTOMREQUEST,'GET');
    curl_setopt ($ch, CURLOPT_HEADER, 0);
    $exec=curl_exec ($ch);
?>

dump.php:

<?php
    var_dump($_SERVER);
?>

Case 1: http://localhost/dumpx.php?u=y

 'HTTP_USER_AGENT' => string 'booyah!' (length=7)

Case 2: http://localhost/dumpx.php?u=n

No $_SERVER['HTTP_USER_AGENT']

This proves that there is no default user agent for curl: it will just not pass it in the request header

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