REST – What You Did Not Know

Over the last few years, we have started taking for granted that data sources feeding for content, mobile device service feeds, or cloud computing are all driven by modern technologies, such as RESTful web services. Everybody has been talking about how their stateless model allows applications to scale easily and how it emphasizes on clear decoupling between data provisioning and data consumption. Nowadays, architects have started introducing the concept of microservices, aiming to reduce the complexity in systems by splitting their core components into small independent pieces that simply do a single task. So, enterprise-grade software is about to become a composite of such microservices. This makes it easy to maintain, and allows better life cycle management when new parts need to be introduced. Unsurprisingly, most of the microservices are serviced by RESTful frameworks. This fact may leave the impression that REST was invented sometime in the last decade, but that is far from the truth. In fact, REST has been around since the last decade of the previous century!

This chapter will walk you through the foundation of Representational State Transfer (REST) and will explain how REST couples with the HTTP protocol. You will look into five key principles that have to be considered while turning any HTTP application into a RESTful service-enabled application. You will also look at the differences between describing RESTful and classic Simple Object Access Protocol (SOAP)-based web services. Finally, you will learn how to utilize already-existing infrastructure for your benefit.

In this chapter, we will cover the following topics:

• REST fundamentals
• REST with HTTP
• Essential differences in the description, discovery, and documentation of RESTful services compared to classical SOAP-based services
• Taking advantage of existing infrastructure