nginx.conf

user  nginx;
worker_processes  auto;

error_log  /dev/stdout error;
pid        /var/run/nginx.pid;


events {
    worker_connections  1024;
}


http {
    include       /etc/nginx/mime.types;
    default_type  application/octet-stream;

    log_format  main  '[$time_local] $status "$http_x_forwarded_for" "$request"';

    access_log  /var/log/nginx/access.log  main;

    sendfile        on;
    #tcp_nopush     on;

    keepalive_timeout  65;

    # Do not use etags for caching:
    etag off;
    # Last-Modified is always added anyway.
    
    server {
        listen       80;
        server_name  localhost;

        error_log /var/log/nginx/error.log;
     
        root /usr/share/nginx/html;

        location /assets {
            # Strongly cache these things for at least 30 days:
            add_header Cache-Control "public, max-age=2592000, no-transform";
            try_files $uri @default;
        }

        location ~ index\.(physics|chemistry|biology)\.html$ {
            # Index pages, and also serves unknown URLs too from @default.
            # Do not allow caching of these index pages at all:
            add_header Cache-Control "no-cache, no-store, must-revalidate";
            try_files $uri @default;
        }

        location / {
            # Everything else.
            # Allow caching, but require revalidation every time:
            add_header Cache-Control "no-cache, must-revalidate";
            try_files $uri @default;
        }

        location @default {
            # Unknown files not found by any of the try_files above.
            # No headers can be added in this block, since they won't be used.
            # Rewrite all unknown requests to the relevant index page:
            if ($http_host ~ physics|8000) {
                rewrite .* /index.physics.html last;
            }
            if ($http_host ~ chemistry|8001) {
                rewrite .* /index.chemistry.html last;
            }
            if ($http_host ~ biology|8002) {
                rewrite .* /index.biology.html last;
            }
        }
    }
}