Real-Time Phoenix

Add Real-Time Out-Of-Stock Alerts

The last feature that we will add to our shopping cart is out-of-stock alerts. A shopping cart consists of a set of items that have been added by a shopper. The shopping cart will notify the shopper when any of these items goes out-of-stock. If you remember from the CartView module, an item will be determined to be available (or not) each time that the cart is rendered—all that we need to do is trigger the cart to be rendered and sent to the connected client.

We’ll leverage PubSub to know when the ShoppingCartChannel needs to send a message to the client. Our PubSub usage so far in this book has been tied to Channels—we’ve always pushed directly to a Channel topic. We can take a different approach, though. ...