config nginx

server {
  listen 80;
  server_name example.com;

  location /.well-known/acme-challenge/ {
    root /var/www/letsencrypt;
  }

  location / {
    return 301 https://$host$request_uri;
  }
}

server {
  listen 443 ssl http2;
  listen [::]:443 ssl http2;

  server_name example.com;


  ssl_certificate /etc/letsencrypt/live/example.com/fullchain.pem;
  ssl_certificate_key /etc/letsencrypt/live/example.com/privkey.pem;

  ssl_dhparam  /etc/letsencrypt/live/example.com/dhparam.pem;

  location /socket.io/ {
    proxy_set_header Upgrade $http_upgrade;
    proxy_set_header Connection "upgrade";
    proxy_pass "http://localhost:5000/socket.io/";
  }

  location / {
        try_files /_not_exists_ @backend;
  }

  location @backend {
    proxy_pass       http://127.0.0.1:5000;
    proxy_set_header X-Real-IP $remote_addr;
    proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
    proxy_set_header Host $http_host;

    proxy_http_version 1.1;
    proxy_set_header Upgrade $http_upgrade;
    proxy_set_header Connection "upgrade";
  }
}