So far, the customer support team at CCM has been relying only on e-mails to interact with individual users. They've recently added the RabbitMQ-powered public address system discussed in Chapter 3, Switching to Server-push. Now that direct user messages can get routed to users by e-mails, they're interested in the possibility of sending such messages to individual users from the back office application. Furthermore, if possible they would like users who don't have an inbox queue on RabbitMQ to get the message e-mailed to them immediately instead of having to wait for the seven days' TTL.

In terms of messaging architecture, you're in a known territory; this is the exact same model as the one you put in place in Chapter 2, Creating an Application Inbox, for user-to-user messages, as illustrated in the following screenshot. The only difference is that, unlike the main application, the back office will not create and bind a user queue prior to sending a message. Instead...