如何使用 cURL 找到我将被重定向的位置?

I'm trying to make curl follow a redirect but I can't quite get it to work right. I have a string that I want to send as a GET param to a server and get the resulting URL.

Example:

String = Kobold Vermin
Url = www.wowhead.com/search?q=Kobold+Worker

If you go to that url it will redirect you to "www.wowhead.com/npc=257". I want curl to return this URL to my PHP code so that i can extract the "npc=257" and use it.

Current code:

function npcID($name) {
    $urltopost = "http://www.wowhead.com/search?q=" . $name;
    $ch = curl_init();
    curl_setopt($ch, CURLOPT_USERAGENT, "Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.8.1.1) Gecko/20061204 Firefox/2.0.0.1");
    curl_setopt($ch, CURLOPT_URL, $urltopost);
    curl_setopt($ch, CURLOPT_REFERER, "http://www.wowhead.com");
    curl_setopt($ch, CURLOPT_HTTPHEADER, Array("Content-Type:application/x-www-form-urlencoded"));
    curl_setopt($ch, CURLOPT_FOLLOWLOCATION, TRUE);
    return curl_getinfo($ch, CURLINFO_EFFECTIVE_URL);
}

This however returns www.wowhead.com/search?q=Kobold+Worker and not www.wowhead.com/npc=257.

I suspect PHP is returning before the external redirect happens. How can I fix this?

解决方案

To make cURL follow a redirect, use:

curl_setopt($ch, CURLOPT_FOLLOWLOCATION, true);

Erm... I don't think you're actually executing the curl... Try:

curl_exec($ch);

...after setting the options, and before the curl_getinfo() call.

EDIT: If you just want to find out where a page redirects to, I'd use the advice here, and just use Curl to grab the headers and extract the Location: header from them:

$ch = curl_init();
curl_setopt($ch, CURLOPT_URL, $url);
curl_setopt($ch, CURLOPT_HEADER, true);
curl_setopt($ch, CURLOPT_FOLLOWLOCATION, false);
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
$result = curl_exec($ch);
if (preg_match('~Location: (.*)~i', $result, $match)) {
   $location = trim($match[1]);
}