Elm + Phoenix

An updated version of seat_saver

Last year, CultivateHQ made a series of tutorials how out to make Elixir talk with Elm. Since then, Elm has gone through some major breaking changes. This is simply an updated version of that app.

Running the app:

git clone [email protected]:crenwick/seat_saver.git
cd seat_saver

# For the http app (non phoenix channels), 
# run `git checkout http`

mix deps.get
mix ecto.create && mix ecto.migrate && mix run priv/repo/seeds.exs
npm install # this will install elm packages too

iex -S mix phoenix.server # requires postgres running

Now you can visit localhost:4000 from your browser.

Differences between this and CultivateHQ/seat_saver

Elixir:

Both have identical http setups (via the http branch), and both have almost identical Elixir setups. However, the SeatSaver.SeatsChannel route of request_seat replies with the new seat object (instead of {:noreply}). The Elm app uses this reply to update the model.

Elm:

Unlike CultivateHQ's version, this app does not use ports with the web/static/js/socket.js file. Instead, it uses a native implmentation of WebSockets/Phoenix channels via the elm-phoenix-socket package. This ends up with a cleaner, more Elm-like implmentation. However, unlike Phoenix' socket.js, Elm's WebSockets does not fall back to longpolling.

Like CultivateHQ's, when this app loads it sets up a listener on both set_seats and seat_updated channels. However, this app also handles the reply from the request_seat request and updates the model with that, too.