PHP cURL：获取重定向的目标，而不是跟踪它 [英] PHP cURL: Get target of redirect, without following it

问题描述

curl_getinfo函数返回有关HTTP请求结果的大量元数据。但是，由于某种原因，它不包括我想要的信息位，这是目标URL，如果请求返回一个HTTP重定向代码。

I没有使用CURLOPT_FOLLOWLOCATION，因为我想在特殊情况下处理特定的重定向代码。

如果cURL可以跟踪重定向，为什么不能告诉我他们重定向到什么时候它不是跟随他们？

当然，我可以设置CURLOPT_HEADER标志，并选择位置头。

解决方案

这可以通过4个简单的步骤完成：

步骤1.初始化curl

  curl_init（$ ch）; //初始化curl句柄
 // COOKIESESSION是可选的，如果你想保存cookie在内存中使用
 curl_setopt（$ this-> ch，CURLOPT_COOKIESESSION，true）; 
  

步骤2.获取 $ url

  curl_setopt（$ ch，CURLOPT_URL，$ url）; //指定您的网址
 curl_setopt（$ ch，CURLOPT_HEADER，true）; // include header in http data 
 curl_setopt（$ ch，CURLOPT_FOLLOWLOCATION，false）; // do not follow redirects 
 $ http_data = curl_exec（$ ch）; // hit the $ url 
 $ curl_info = curl_getinfo（$ ch）; 
 $ headers = substr（$ http_data，0，$ curl_info ['header_size']）; // split out header 
  

步骤3.检查您是否有正确的响应代码

  if（！（$ curl_info ['http_code']> 299&& $ curl_info ['http_code']< 309） 
 // return，echo，die，whatever you like 
 return'Error  -  http code'.curl_info ['http_code']。收到。 
} 
  

步骤4.解析标题以获取新网址

  preg_match（！\r\\\
（？：Location | URI）：*（。*？）* \r\\\
 ！，$ headers，$ matches）; 
 $ url = $ matches [1]; 
  

一旦你有了新的URL，你可以重复步骤2-4， / p>

The curl_getinfo function returns a lot of metadata about the result of an HTTP request. However, for some reason it doesn't include the bit of information I want at the moment, which is the target URL if the request returns an HTTP redirection code.

I'm not using CURLOPT_FOLLOWLOCATION because I want to handle specific redirect codes as special cases.

If cURL can follow redirects, why can't it tell me what they redirect to when it isn't following them?

Of course, I could set the CURLOPT_HEADER flag and pick out the Location header. But is there a more efficient way?

解决方案

This can be done in 4 easy steps:

Step 1. Initialise curl

curl_init($ch); //initialise the curl handle
//COOKIESESSION is optional, use if you want to keep cookies in memory
curl_setopt($this->ch, CURLOPT_COOKIESESSION, true);

Step 2. Get the headers for $url

curl_setopt($ch, CURLOPT_URL, $url); //specify your URL
curl_setopt($ch, CURLOPT_HEADER, true); //include headers in http data
curl_setopt($ch, CURLOPT_FOLLOWLOCATION, false); //don't follow redirects
$http_data = curl_exec($ch); //hit the $url
$curl_info = curl_getinfo($ch);
$headers = substr($http_data, 0, $curl_info['header_size']); //split out header

Step 3. Check if you have the correct response code

if (!($curl_info['http_code']>299 && $curl_info['http_code']<309)) {
  //return, echo, die, whatever you like
  return 'Error - http code'.curl_info['http_code'].' received.';
}

Step 4. Parse the headers to get the new URL

preg_match("!\r\n(?:Location|URI): *(.*?) *\r\n!", $headers, $matches);
$url = $matches[1];

Once you have the new URL you can then repeat steps 2-4 as often as you like.

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