Chapter 5. Using the API

Red Hat build of Rhea is an asynchronous event-driven API. To define how the application handles events, the user registers event-handling functions on the container object. These functions are then called as network activity or timers trigger new events.

var rhea = require("rhea");
var container = rhea.create_container();

container.on("sendable", function (event) {
    console.log("A message can be sent");
});

container.on("message", function (event) {
    console.log("A message is received");
});

These are only a few common-case events. The full set is documented in the Rhea API reference.

The event argument has attributes for accessing the object the event is regarding. For example, the connection_open event sets the event connection attribute.

In addition to the primary object for the event, all objects that form the context for the event are set as well. Attributes with no relevance to a particular event are null.

event.container
event.connection
event.session
event.sender
event.receiver
event.delivery
event.message

The container is the top-level API object. It is the entry point for creating connections, and it is responsible for running the main event loop. It is often constructed with a global event handler.

var rhea = require("rhea");
var container = rhea.create_container();

Each container instance has a unique identity called the container ID. When Red Hat build of Rhea makes a network connection, it sends the container ID to the remote peer. To set the container ID, pass the id option to the create_container method.

var container = rhea.create_container({id: "job-processor-3"});

If the user does not set the ID, the library will generate a UUID when the container is constructed.