Real-Time Phoenix

Track Shopping Carts in Real-Time

We’ll use Presence to track each ShoppingCartChannel and the shopper’s cart item IDs. Each change to a cart will dispatch an update to the CartTracker, and the admin client will automatically receive the changes. Our process for this task will break down into these steps:

1. Create a CartTracker module using Phoenix.Presence.
2. Connect ShoppingCartChannel to the CartTracker.
3. Send cart updates to the CartTracker.
4. Configure admin.js to receive Presence updates.
5. Aggregate and display the information in the dashboard.

First, create the CartTracker module under the sneakers_23_web/channels directory.

sneakers_23_admin/lib/sneakers_23_web/channels/cart_tracker.ex

defmodule Sneakers23Web.CartTracker do
  use Phoenix.Presence, ...