get_headers 不一致 [英] get_headers Inconsistency
问题描述
运行以下代码
var_dump(get_headers("http://www.domainnnnnnnnnnnnnnnnnnnnnnnnnnnn.com/CraxyFile.jpg"));
对于任何不存在的域或 URL 返回 HTTP 200 而不是 404
Array
(
[0] => HTTP/1.1 200 OK
[1] => Server: nginx/1.1.15
[2] => Date: Mon, 08 Oct 2012 12:29:13 GMT
[3] => Content-Type: text/html; charset=utf-8
[4] => Connection: close
[5] => Set-Cookie: PHPSESSID=3iucojet7bt2peub72rgo0iu21; path=/; HttpOnly
[6] => Expires: Thu, 19 Nov 1981 08:52:00 GMT
[7] => Cache-Control: no-store, no-cache, must-revalidate, post-check=0, pre-check=0
[8] => Pragma: no-cache
[9] => Set-Cookie: bypassStaticCache=deleted; expires=Thu, 01-Jan-1970 00:00:01 GMT; path=/; httponly
[10] => Set-Cookie: bypassStaticCache=deleted; expires=Thu, 01-Jan-1970 00:00:01 GMT; path=/; httponly
[11] => Vary: Accept
)
如果你跑了
var_dump(get_headers("http://www.domain.com/CraxyFile.jpg"));
你得到
Array
(
[0] => HTTP/1.1 404 Not Found
[1] => Date: Mon, 08 Oct 2012 12:32:18 GMT
[2] => Content-Type: text/html
[3] => Content-Length: 8727
[4] => Connection: close
[5] => Server: Apache
[6] => Vary: Accept-Encoding
)
在很多例子中,get_headers
已被证明是验证现有 URL 的解决方案
They are so many instances where get_headers
has been proven to be a solution to validate existing URL
发现CURL也有同样的问题
Got to find out that CURL also has the same issue
$curl = curl_init();
curl_setopt_array($curl, array(CURLOPT_RETURNTRANSFER => true,CURLOPT_URL => 'idontexist.tld'));
curl_exec($curl);
$info = curl_getinfo($curl);
curl_close($curl);
var_dump($info);
推荐答案
问题与域名长度无关,只是域名是否存在.
The problem is nothing to do with the length of the domain name, it is simply whether the domain exists.
您使用的 DNS 服务将不存在的域解析到服务器,该服务器为您提供友好"错误页面,并返回 200 响应代码.这意味着它也不是 get_headers()
的问题,具体来说,它是任何潜在依赖于合理 DNS 查找的过程.
You are using a DNS service that resolves non-existent domains to a server that gives you a "friendly" error page, which it returns with a 200 response code. This means it is also not a problem with get_headers()
specifically, it is any procedure with an underlying reliance on sensible DNS lookups.
无需为您工作的每个环境硬编码变通方法即可处理此问题的方法可能如下所示:
A way to handle this without hardcoding a work around for every environment you work in might look something like this:
// A domain that definitely does not exist. The easiest way to guarantee that
// this continues to work is to use an illegal top-level domain (TLD) suffix
$testDomain = 'idontexist.tld';
// If this resolves to an IP, we know that we are behind a service such as this
// We can simply compare the actual domain we test with the result of this
$badIP = gethostbyname($testDomain);
// Then when you want to get_headers()
$url = 'http://www.domainnnnnnnnnnnnnnnnnnnnnnnnnnnn.com/CraxyFile.jpg';
$host = parse_url($url, PHP_URL_HOST);
if (gethostbyname($host) === $badIP) {
// The domain does not exist - probably handle this as if it were a 404
} else {
// do the actual get_headers() stuff here
}
您可能希望以某种方式缓存第一次调用 gethostbyname()
的返回值,因为您知道您正在查找一个不存在的名称,这通常需要几秒钟.
You may want to somehow cache the return value of the first call to gethostbyname()
, since you know you are looking up a name that does not exist, and this can often take a few seconds.
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