Architecting the Cloud: Design Decisions for Cloud Computing Service Models (SaaS, PaaS, and IaaS)

Chapter 6

The Key to the Cloud

Restful Services

Life is a distributed object system. However, communication among humans is a distributed hypermedia system, where the mind’s intellect, voice+gestures, eyes+ears, and imagination are all components.

—Roy T. Fielding, inventor of REST

There are many reasons that Representational State Transfer (RESTful) services are a critical component of any cloud solution. First, when building services in the cloud one typically builds on top of an Infrastructure as a Service (IaaS) or Platform as a Service (PaaS) provider or integrates with one-to-many Software as a Service (SaaS) offerings. All of these cloud service providers have exposed their application programming interfaces (APIs) using RESTful services. In addition, clouds are heterogeneous ecosystems that connect many different services from many different companies written in many different technology stacks. The complexities of the underlying stacks and protocols should be abstracted away from the business logic so this ecosystem of services can easily connect and work in harmony.

A great example of this concept in practice is how simply we can plug in social media functionality from Facebook, Twitter, Pinterest, and other social media touchpoints. Underneath those widely used APIs are some very diverse and complex systems. These high-scale systems combine multiple programming stacks, multiple database technologies, and technologies for integration, caching, queuing, event processing, ...