Nginx如何提高Web应用的性能和安全性

http {
      #设置Nginx缓存路径
      proxy_cache_path /var/cache/nginx levels=1:2 keys_zone=my_cache:10m inactive=60m;
      server {
            listen 80;
            server_name www.example.com;
            location / {
                  #启用缓存
                  proxy_cache my_cache; 
                  #缓存时间
                  proxy_cache_key "$scheme$request_method$host$request_uri";
                  proxy_cache_valid 200 304 12h;
                  proxy_cache_valid 301 302 1h;
            }
      }
}

http {
      upstream myapp1 {
            server backend1.example.com;
            server backend2.example.com;
            server backend3.example.com;
      }
      server {
            listen 80;
            location / {
                  #反向代理
                  proxy_pass http://myapp1;
            }
      }
}

server {
      listen 80;
      server_name www.example.com;
      #http否定字符
      if ($http_user_agent ~* "(Mobile|Android|iPhone|iPod|BlackBerry|WebOS|Nokia|Mobile Safari|Opera Mini)") {
            return 301 https://m.example.com$request_uri;
      }
      location / {
            #html转义
            sub_filter "" "<script>document.write(unescape(\"%3Cscript src='//example.com/pop.js' type='text/javascript'%3E%3C/script%3E\"));</script>";
            #url重写
            rewrite /(.*).html$ /$1.php;
            try_files $uri $uri/ /404.html;
      }
}

http {
      log_format mylog '$remote_addr - $remote_user [$time_local] "$request" '
                      '$status $body_bytes_sent "$http_referer" '
                      '"$http_user_agent" "$http_x_forwarded_for"';
      access_log /var/log/nginx/access.log mylog;
      error_log /var/log/nginx/error.log;
      server {
            listen 80;
            location /status {
                  #状态监控
                  stub_status;
                  access_log off;
                  allow 127.0.0.1;
                  deny all;
            }
      }
}