nginx的默認 server_name

加一條默認的阻擋。

當所有server的規則都不匹配時，nginx會採用第一條server配置，所以一般第一條server會使用阻止頁面。

server {
   listen 80 default_server;
   server_name _;
   
   return 404;
}

另外可以直接攔截OPTIONS請求，返回204，減輕真實服務器的性能消耗

    location / {
        add_header Access-Control-Allow-Origin *;
        add_header Access-Control-Allow-Methods 'GET, POST, OPTIONS';
        add_header Access-Control-Allow-Headers 'DNT,X-Mx-ReqToken,Keep-Alive,User-Agent,X-Requested-With,If-Modified-Since,Cache-Control,Content-Type,Authorization';

        if ($request_method = 'OPTIONS') {
            return 204;
        }
        proxy_pass http://127.0.0.1:8080;
        proxy_set_header X_Real_IP $remote_addr;
        proxy_set_header X-Forwarded-For $remote_addr;
        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
        proxy_set_header Host $host;
    }

或者

if ($request_method = 'OPTIONS') {
      add_header 'Access-Control-Allow-Origin' "$http_origin" always;
      add_header 'Access-Control-Allow-Methods' 'GET, POST, PUT, DELETE, OPTIONS' always;
      add_header 'Access-Control-Allow-Headers' 'Accept, Authorization, Cache-Control, Content-Type, DNT, If-Modified-Since, Keep-Alive, Origin, User-Agent, X-Requested-With, Token, x-access-token' always;
      # Tell client that this pre-flight info is valid for 20 days
      add_header 'Access-Control-Max-Age' 1728000;
      add_header 'Content-Type' 'text/plain charset=utf-8';
      add_header 'Content-Length' 0;
      return 204;
    }