user daemon daemon;
worker_processes  auto;

events {
    use                 epoll;
    worker_connections  1024;
    multi_accept        on;
}

http {
    server {
        listen 4001;

        location / {
            proxy_pass http://localhost:4000;
            proxy_set_header Upgrade $http_upgrade;
            proxy_set_header Connection "upgrade";

            if ($request_method = 'OPTIONS') {
                add_header 'Access-Control-Allow-Origin' '*' always;
                add_header 'Access-Control-Allow-Methods' 'GET, POST, OPTIONS, DELETE';
                add_header 'Access-Control-Allow-Headers' 'DNT,User-Agent,X-Requested-With,If-Modified-Since,Cache-Control,Content-Type,Range,Authorization';
                add_header 'Access-Control-Max-Age' 1728000;
                add_header 'Content-Type' 'text/plain; charset=utf-8';
                add_header 'Content-Length' 0;
                return 204;
            }

            if ($request_method = 'POST') {
                add_header 'Access-Control-Allow-Origin' '*' always;
                add_header 'Access-Control-Allow-Methods' 'GET, POST, OPTIONS, DELETE';
                add_header 'Access-Control-Allow-Headers' 'DNT,User-Agent,X-Requested-With,If-Modified-Since,Cache-Control,Content-Type,Range';
                add_header 'Access-Control-Expose-Headers' 'Content-Length,Content-Range';
            }

            if ($request_method = 'GET') {
                add_header 'Access-Control-Allow-Origin' '*' always;
                add_header 'Access-Control-Allow-Methods' 'GET, POST, OPTIONS, DELETE';
                add_header 'Access-Control-Allow-Headers' 'DNT,User-Agent,X-Requested-With,If-Modified-Since,Cache-Control,Content-Type,Range,Authorization';
                add_header 'Access-Control-Expose-Headers' 'Content-Length,Content-Range';
            }

            if ($request_method = 'DELETE') {
                add_header 'Access-Control-Allow-Origin' '*' always;
                add_header 'Access-Control-Allow-Methods' 'GET, POST, OPTIONS, DELETE';
                add_header 'Access-Control-Allow-Headers' 'DNT,User-Agent,X-Requested-With,If-Modified-Since,Cache-Control,Content-Type,Range,Authorization';
                add_header 'Access-Control-Expose-Headers' 'Content-Length,Content-Range';
            }
        }
    }
}