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 or name of the server processing the request if the Host header is not available.

This variable may have a different value from $http_host in such cases: 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 value of 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。