Romaji to Kana Converter: Angular & Express — Chapter 8, Exercise 2
=====================================================================

TASK
Configure the nginx location /romaji/ block against a real running
instance of the app (a second local nginx config is fine for
testing), and confirm both a page load and a real /api/convert
request succeed through the proxy, with server.js completely
unchanged from Chapter 7.

SOLUTION

// /etc/nginx/sites-available/romaji-test (a local test vhost, e.g.
// listening on port 8080 so it doesn't collide with anything else)

  server {
      listen 8080;
      server_name localhost;

      location /romaji/ {
          proxy_pass http://localhost:4000/;
          proxy_set_header Host $host;
          proxy_set_header X-Real-IP $remote_addr;
      }
  }

  $ sudo ln -s /etc/nginx/sites-available/romaji-test /etc/nginx/sites-enabled/
  $ sudo nginx -t && sudo systemctl reload nginx

With the real Express server from Chapter 7 already running on port
4000 (server.js completely untouched -- no edits made to it for this
exercise at all):

  $ curl -s http://localhost:8080/romaji/ | grep -o '<title>[^<]*'
  <title>Romaji to Kana Converter

  $ curl -s -X POST http://localhost:8080/romaji/api/convert \
      -H "Content-Type: application/json" -d '{"romaji":"sushi"}'

  {"hiragana":"すし","katakana":"スシ"}

Both requests succeed through the proxy. Checking Express's own
console output during the second request confirms it logged the
request as arriving at exactly /api/convert -- the /romaji prefix
was genuinely stripped by nginx before Express ever saw the request,
not handled by any code inside server.js.

WHY THIS WORKS AS AN ANSWER
----------------------------
It confirms the trailing-slash prefix-stripping behavior this chapter
describes actually happens, for both a static page request and a real
API POST request, using an entirely real nginx config and a real
running Express process with zero changes made to server.js. Express
routes /api/convert exactly as it has since Chapter 5, with no
awareness that a reverse proxy or a /romaji prefix exist at all --
the path-mounting is handled entirely at the nginx layer.