Getting Started with REST API Development

A web service is a communication mechanism defined between various computer systems. Without web services, custom peer-to-peer communication becomes cumbersome and platform-specific. The web needs to understand and interpret a hundred different things in the form of protocols. If computer systems can align with the protocols that the web can understand easily, it is a great help.

A web service is a software system designed to support interoperable machine-to-machine interaction over a network, as defined by the World Wide Web Consortium (W3C) at https://www.w3.org/TR/ws-arch/.

Now, in simple words, a web service is a road between two endpoints where messages are transferred smoothly. The message transfer is usually one way. Two individual programmable entities can also communicate with each other through their own APIs. Two people communicate through language, two applications communicate through an Application Programming Interface (API).

The reader might be wondering; what is the importance of the API in the current digital world? The rise of the Internet of Things (IoT) made API usage heavier than before. Awareness of APIs is growing day by day, and there are hundreds of APIs that are being developed and documented all over the world every day. Notable major businesses are seeing the future in the API as a Service (AaS). A bright example in recent times is Amazon Web Services (AWS). AWS is a huge success in the cloud world. Developers write their own applications using the Representational State Transfer (REST) API provided by AWS and access it via Command-Line Interface (CLI). 

A few more hidden use cases are from travel sites such as http://Booking.com and https://www.expedia.com/, which fetch real-time prices by calling the APIs of third-party gateways and data vendors. Web service usage is often charged these days by the amount of data requests.

In this chapter, we will focus on the following topics:

• The different web services available
• REST architecture in detail
• The rise of Single-page applications (SPAs) with REST
• Setting up a Go project and running a development server
• Building our first service for finding the fastest mirror site from a list of Debian servers hosted worldwide
• The Open API specification and Swagger documentation