Nginx中$http_host、$host、$proxy_host的区别

摘抄地址，感谢作者！

一 被代理的服务器2的端口不是80

服务器1的配置：

[root@ans3 conf]# cat nginx.conf

#user  nobody;
worker_processes  1;

#error_log  logs/error.log;
#error_log  logs/error.log  notice;
error_log  logs/error.log  info;

#pid        logs/nginx.pid;


events {
    worker_connections  1024;
}


http {
    include       mime.types;
    default_type  application/octet-stream;

    log_format  main  '$remote_addr - $remote_user [$time_local] "$request" '
                      '$status $body_bytes_sent "$http_referer" '
                      '"$http_user_agent" "$http_x_forwarded_for"';

    access_log  logs/access.log  main;

    sendfile        on;
    tcp_nopush     on;

    #keepalive_timeout  0;
    keepalive_timeout  65;

    #gzip  on;
#     upstream backend {
#       server 10.0.0.50:8080;
#}

    server {
          listen       80;
          server_name  a.test.com;

    location / {
        proxy_pass http://10.0.0.50:8080;
        proxy_set_header X-Proxy-Host $proxy_host;
        proxy_set_header Host $http_host;
           index index.html index.htm;
       }
}
}

服务器2的配置

[root@master conf]# cat nginx.conf

#user  nobody;
worker_processes  1;

#error_log  logs/error.log;
#error_log  logs/error.log  notice;
#error_log  logs/error.log  info;

#pid        logs/nginx.pid;


events {
    worker_connections  1024;
}


http {
    include       mime.types;
    default_type  application/octet-stream;

    #log_format  main  '$remote_addr - $remote_user [$time_local] "$request" '
    #                  '$status $body_bytes_sent "$http_referer" '
    #                  '"$http_user_agent" "$http_x_forwarded_for"';

    #access_log  logs/access.log  main;

    sendfile        on;
    #tcp_nopush     on;

    #keepalive_timeout  0;
    keepalive_timeout  65;

    #gzip  on;

    server {
        listen       8080;
        server_name  www.test.com aa.test.com;


        location / {
      return 200 'http_host=[$http_host] host=[$host] proxy_host=[$http_x_proxy_host]\n';
}
}
}

不带请求头 Host

[root@ans3 conf]# curl -H 'Host:' --http1.0 http://a.test.com

http_host=[] host=[www.test.com] proxy_host=[10.0.0.50:8080]

携带请求头 Host

[root@ans3 conf]# curl -H 'Host:abc:123' --http1.0 http://a.test.com

http_host=[abc:123] host=[abc] proxy_host=[10.0.0.50:8080]

被代理的服务器2的端口是80

服务器1的配置

http {
    include       mime.types;
    default_type  application/octet-stream;

    log_format  main  '$remote_addr - $remote_user [$time_local] "$request" '
                      '$status $body_bytes_sent "$http_referer" '
                      '"$http_user_agent" "$http_x_forwarded_for"';

    access_log  logs/access.log  main;

    sendfile        on;
    tcp_nopush     on;

    #keepalive_timeout  0;
    keepalive_timeout  65;

    #gzip  on;
#     upstream backend {
#       server 10.0.0.50:8080;
#}

    server {
          listen       80;
          server_name  a.test.com;
        
    location / {
        proxy_pass http://10.0.0.50:80;
        proxy_set_header X-Proxy-Host $proxy_host;
        proxy_set_header Host $http_host;
           index index.html index.htm;
       }
}
}

服务器2的配置

http {
    include       mime.types;
    default_type  application/octet-stream;

    #log_format  main  '$remote_addr - $remote_user [$time_local] "$request" '
    #                  '$status $body_bytes_sent "$http_referer" '
    #                  '"$http_user_agent" "$http_x_forwarded_for"';

    #access_log  logs/access.log  main;

    sendfile        on;
    #tcp_nopush     on;

    #keepalive_timeout  0;
    keepalive_timeout  65;

    #gzip  on;

    server {
        listen       80;
        server_name www.test.com aa.test.com;


        location / {
      return 200 'http_host=[$http_host] host=[$host] proxy_host=[$http_x_proxy_host]\n';
}
}
}

此时的 $proxy_host 会省略80端口

[root@ans3 conf]# curl -H 'Host:abc:123' --http1.0 http://a.test.com

http_host=[abc:123] host=[abc] proxy_host=[10.0.0.50]

ngx_http_core_module 文档中对 $host 的定义

in this order of precedence: host name from the request line, or host name from the “Host” request header field, or the server name matching a request

ngx_http_proxy_module 文档中对 $proxy_host 的定义

name and port of a proxied server as specified in the proxy_pass directive;

下面这个示例也能看出 $http_host 和 $host 的区别