Event-Driven Architecture Protocols

Motivation

The HTTP protocol is suitable for transferring data between client and server. However, for real-time communication, such as instant messaging, live streaming, gaming, and so on, HTTP falls short due to the connection terminating after a response from the server. The HTTP-based techniques to fetch updated data also have limitations. For example, short polling sends too many unnecessary requests, long polling uses two separate connections for sending and receiving data, and HTTP streaming allows only half-duplex communication. Event-driven architecture addresses all these limitations of HTTP-based techniques.

Event-driven architecture

Event-driven architecture (EDA) is an approach that centers around events for data and applications. The event-driven architecture enables applications to act or react to those events. A client gets the data whenever an event is triggered in the application without requesting the server. The problems associated with short and long polling are eliminated by using an event-driven approach. This is very much in contrast with the traditional REST API approach to request the updated data after a certain interval or when needed. The illustration below explains the concept.