PHP 中的 HTTP_HOST 和 SERVER_NAME 有什么区别? [英] What is the difference between HTTP_HOST and SERVER_NAME in PHP?

问题描述

$_SERVER['HTTP_HOST'] 和 $_SERVER['SERVER_NAME'] 在 PHP 中有什么区别?

What is the difference between $_SERVER['HTTP_HOST'] and $_SERVER['SERVER_NAME'] in PHP?

您什么时候会考虑使用一种而不是另一种，为什么?

When would you consider using one over the other and why?

推荐答案

HTTP_HOST 来自 HTTP 请求标头，这是客户端实际用作请求的目标主机"的内容.SERVER_NAME 在服务器配置中定义.使用哪一种取决于你需要它做什么.但是，您现在应该意识到，一个是客户端控制的值，因此在业务逻辑中使用可能不可靠，而另一个是服务器控制的值，它更可靠.但是，您需要确保有问题的网络服务器正确配置了 SERVER_NAME.以 Apache HTTPD 为例，这里摘自 其文档:

The HTTP_HOST is obtained from the HTTP request header and this is what the client actually used as "target host" of the request. The SERVER_NAME is defined in server config. Which one to use depends on what you need it for. You should now however realize that the one is a client-controlled value which may thus not be reliable for use in business logic and the other is a server-controlled value which is more reliable. You however need to ensure that the webserver in question has the SERVER_NAME correctly configured. Taking Apache HTTPD as an example, here's an extract from its documentation:

如果未指定 ServerName，则服务器尝试通过对 IP 地址执行反向查找来推断主机名.如果 ServerName 中未指定端口，则服务器将使用传入请求中的端口.为了获得最佳的可靠性和可预测性，您应该使用 ServerName 指令指定显式的主机名和端口.

If no ServerName is specified, then the server attempts to deduce the hostname by performing a reverse lookup on the IP address. If no port is specified in the ServerName, then the server will use the port from the incoming request. For optimal reliability and predictability, you should specify an explicit hostname and port using the ServerName directive.

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更新:在检查Pekka 对您问题的回答后，其中包含指向bobince 的回答，PHP 将始终为 SERVER_NAME 返回 HTTP_HOST 的值，这就是针对几年前我自己的 PHP 4.x + Apache HTTPD 1.2.x 体验，我从 Windows XP 上的当前 XAMPP 环境(Apache HTTPD 2.2.1 和 PHP 5.2.8)中吹走了一些灰尘，启动它，创建一个打印这两个值的 PHP 页面，使用 URLConnection 修改 Host 标头和测试告诉我这确实(不正确)是这种情况.

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Update: after checking the answer of Pekka on your question which contains a link to bobince's answer that PHP would always return HTTP_HOST's value for SERVER_NAME, which goes against my own PHP 4.x + Apache HTTPD 1.2.x experiences from a couple of years ago, I blew some dust from my current XAMPP environment on Windows XP (Apache HTTPD 2.2.1 with PHP 5.2.8), started it, created a PHP page which prints the both values, created a Java test application using URLConnection to modify the Host header and tests taught me that this is indeed (incorrectly) the case.

在第一次怀疑 PHP 并挖掘一些 PHP 错误之后关于该主题的报告，我了解到问题的根源在于所使用的 Web 服务器，当请求 SERVER_NAME 时，它错误地返回了 HTTP Host 标头.所以我深入研究了 Apache HTTPD 错误报告 使用关于主题的各种关键字我终于找到了一个相关错误.这种行为是从 Apache HTTPD 1.3 开始引入的.您需要设置 UseCanonicalName 指令on 在 httpd.conf 中 ServerName 的 条目中(也检查警告文档的底部！).

After first suspecting PHP and digging in some PHP bug reports regarding the subject, I learned that the root of the problem is in web server used, that it incorrectly returned HTTP Host header when SERVER_NAME was requested. So I dug into Apache HTTPD bug reports using various keywords regarding the subject and I finally found a related bug. This behaviour was introduced since around Apache HTTPD 1.3. You need to set UseCanonicalName directive to on in the <VirtualHost> entry of the ServerName in httpd.conf (also check the warning at the bottom of the document!).

<VirtualHost *>
    ServerName example.com
    UseCanonicalName on
</VirtualHost> 

这对我有用.

总而言之，SERVER_NAME 更可靠，但您依赖服务器配置！

Summarized, SERVER_NAME is more reliable, but you're dependent on the server config!

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