Using Rails 5 ActionCable and RethinkDB to build a Reactive WebSocket App

In this article we will demonstrate how to build a WebSockets driven application using Rails 5’s ActionCable. By using RethinkDB’s active changefeeds feature we can eliminate the need for a separate event broadcasting service like Redis, resulting in elegant and succinct code.The application that we will be building is a collaborative spreadsheet application much like Google Sheets. It will broadcast to each user the selected cells in different colors, the data in the cells and will guard against multiple users editing the same cell.