Nginx配置如何区分PC或手机访问不同域名

server {
  listen 80;
  server_name www.7d.com 7d.com; // 新官网域名
  rewrite .* https://$host$request_uri last;
}

server {
  listen    443 ssl;
  server_name www.7d.com 7d.com; // 新官网域名
  root /data/7d;
  charset utf-8;
  ssl_certificate /usr/local/nginx/_.7d.com.crt;
  ssl_certificate_key /usr/local/nginx/_.7d.com.key;

  rewrite /s1$ http://s1.7d.com/start last;

  if ( $http_user_agent ~* "(Android|iPhone|Windows Phone|UC|Kindle)" ){ // 跳转判断
    rewrite ^/(.*)$ https://m.7d.com$uri redirect; // redirect表示302跳转（暂时性转移） 
  }   
  ……
}

 server {
  listen 80;
  server_name m.7d.com; // 旧官网域名
  rewrite .* https://$host$request_uri last;
}

server {
  listen    443 ssl;
  server_name m.7d.com; // 旧官网域名
  root /data/7d;
  charset utf-8;
  ssl_certificate /usr/local/nginx/_.7d.com.crt;
  ssl_certificate_key /usr/local/nginx/_.7d.com.key;

  rewrite /s1$ http://s1.7d.com/start last;

  if ( $http_user_agent !~* "(Android|iPhone|Windows Phone|UC|Kindle)" ){ // ~前加个！，如果不是移动端访问，则跳转回新官网。
    rewrite ^/(.*)$ https://m.7d.com$uri redirect; // redirect表示302跳转
  }   
  ……
}