location /socket.io {
    proxy_http_version 1.1;
    proxy_buffering off;
    proxy_set_header Host $http_host;
    proxy_set_header Upgrade $http_upgrade;
    proxy_set_header Connection $proxy_connection;
    proxy_set_header X-Real-IP $remote_addr;
    proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
    proxy_set_header X-Forwarded-Proto $proxy_x_forwarded_proto;
    proxy_set_header X-Forwarded-Ssl $proxy_x_forwarded_ssl;
    proxy_set_header X-Forwarded-Port $proxy_x_forwarded_port;

    # Mitigate httpoxy attack (see README for details)
    proxy_set_header Proxy "";
    proxy_pass http://opaque_web_1:5000;
}