Hello! This is the first HTTP server!

# Server A.
# ---------

server {
    listen 8000;

    location / {
         add_header Content-Type text/html;
         set $html_page '<html>\n';
         set $html_page '${html_page}<h1>Hello! This is the first HTTP server!</h1>\n';
         set $html_page '${html_page}</html>\n';
         return 200 $html_page;
    }
}

# Server B.
# ---------

server {
    listen 9000;

    location / {
         add_header Content-Type text/html;
         set $html_page '<html>\n';
         set $html_page '${html_page}<h1>Ahoy! This is the second HTTP server!</h1>\n';
         set $html_page '${html_page}</html>\n';
         return 200 $html_page;
    }
}

# Redirection proxy
# -----------------

# User environment mapping definition

map $remote_user $target {
   Alice server_a;
   Bob   server_b;
}

server {
    listen 80;

    if ($target ~ "server_a|^$") { # server_a or regex for empty string
        set $target_port 8000;
    }

    if ($target = "server_b" ) {
        set $target_port 9000;
    }

    location / {
        proxy_pass http://127.0.0.1:$target_port;
    }
}