configuration - Nginx 中 $host 和 $http_host 有什么区别

Question

在Nginx中，变量$host和$http_host有什么区别。

Answer 1

$host 是 Core 的变量模块。

$host

This variable is equal to line Host in the header of request orname of the server processing the request if the Host header is notavailable.

This variable may have a different value from $http_host in suchcases: 1) when the Host input header is absent or has an empty value,$host equals to the value of server_name directive; 2)when the valueof Host contains port number, $host doesn't include that port number.$host's value is always lowercase since 0.8.17.

$http_host 也是同一模块的变量，但您不会用该名称找到它，因为它一般定义为 $http_HEADER ( ref ) .

$http_HEADER

The value of the HTTP request header HEADER when converted to lowercase and with 'dashes' converted to 'underscores', e.g. $http_user_agent, $http_referer...;

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总结:

• $http_host 始终等于 HTTP_HOST 请求 header 。
• $host 等于 $http_host，小写且不带端口号(如果存在)，除非 HTTP_HOST 不存在或者为空值。在这种情况下，$host 等于处理请求的服务器的 server_name 指令的值。