Ruby on Rails Training 3 — Final

Solutions for the RoR-3 "Final" module. Built with Rails 8.1 on Ruby 3.3 (matching the Dockerfile).

Map

Generated with lsphere.

Adaptation note (important)

The subject (v1.1) predates Hotwire and asks for jQuery / jquery_ujs / turbolinks and hand-rolled AJAX. That toolchain is obsolete on Rails 8. Every exercise here implements the exact same behaviour the modern, Rails-8-native way, with no extra JavaScript library:

Subject asks for	Implemented with
AJAX partial page updates	Turbo Frames + Turbo Streams
Client-side interactivity	Stimulus (notification sound in ex06)
Real-time / WebSockets	Action Cable via turbo_stream_from broadcasts
Task buffering system	Active Job (broadcast_*_later, fan-out job)
Authentication	Devise

The $refresh counter trick from the subject still holds: because add / edit / destroy / count all update through Turbo Streams, the layout <h1> is never re-rendered in the browser, so the visible counter stays at 1.

Layout

Each exercise is a self-contained Rails app in its own directory:

Dir	App	Feature
ex00	Xnote	Books scaffold + uniqueness; add book without reload
ex01	Xnote	destroy without reload (turbo confirm)
ex02	Xnote	edit in place (form replaces the row, shows errors)
ex03	Xnote	live book count updated on add / delete
ex04	Chat	Devise + real-time chat for all users (Action Cable + Active Job)
ex05	Chat	ChatRooms owned by their creator; messages scoped per room
ex06	Chat	real-time notifications (list + count + sound) for others' messages

Later exercises are copies of the previous one with the new feature added.

Running (development container)

The Dockerfile / docker-compose.yaml provide a Ruby 3.3 dev environment (for cluster machines without Ruby). From the repo root:

docker compose run --service-ports web bash
# then, inside the container, for the exercise you want:
cd ex06/Chat
bundle install
bin/rails db:setup      # creates + migrates + seeds
bin/rails server -b 0.0.0.0

Then open http://localhost:3000.

• Xnote seeds a few sample books.
• Chat seeds three users (alice@chat.dev, bob@chat.dev, carol@chat.dev), all with password password. Open several incognito windows and sign in as different users to see the real-time behaviour (and, in ex06, notifications with sound for messages from other users).

Mail catcher (Mailpit)

docker-compose.yaml includes a Mailpit service that captures all outgoing email (e.g. Devise "forgot password" messages) instead of sending it.

• Web UI to read captured mail: http://localhost:8025
• SMTP endpoint the apps deliver to: mailpit:1025 inside Docker, or localhost:1025 on the host (both configured via SMTP_HOST / SMTP_PORT, see each Chat app's config/environments/development.rb).

docker compose up starts it automatically (the web service depends_on it). To run only the catcher: docker compose up -d mailpit. Then trigger e.g. a password reset from a Chat app and it appears in the Mailpit UI.