Rest API Basics

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REST API

REST is a architecture principles used for designing web services. And REST used nowadays everywhere for client-server communication. Main benefits of REST is scalability, flexibility, independence, and ease of use. HTTP is the foundation for the REST API designs.

Basics of HTTP

Hypertext transfer protocol ak HTTP is a protocol used to transfer data via network. Mainly used for fetching HTML pages and the main data communication on the web.
HTTP is stateless meaning no each request-response cycle is independent from each other. Initially it was mainly used for Clients (like web browsers) to make requests to servers for getting HTML pages. Eventually it started using for server to server communication in the distributed system.

Main REST principles

1. Resource-Based:

Everything is a resource (eg: users, articles, products) and each resource can be identified by URIs (eg: /users/{id}). Resource is mainly text based representation such as JSON, XML or HTML.

2. Stateless:

Every request from a client to a server must contain all the information and context needed to understand the request. The server does not store any context between requests and each requests are isolated.

3. Client-Server:

Client and the server are completely independent. Their communication will only happen using the REST API contract. This enables separation of concerns and make the system modular and easier to maintain.

4 Uniform interface:

The interface between the systems are uniform, making it easier to interact with different resources. This uniformity is achieved through standard HTTP methods

  • GET: Retrieve a resource (read-only)
  • POST: Create a new resource
  • PUT: Update a resource by replacing it entirely
  • PATCH: Partially update a resource
  • DELETE: Remove a resource

5. Cacheable:

With REST API responses can make it cacheable and reduce latency and load on servers.

6 Layered System:

The layered system constraint in REST requires that components in the architecture are organized into layers, where each layer has a specific role and can only interact with its neighboring layers. Client can’t tell whether it’s communicating directly with the end server or with an intermediary server.
Examples of layers: Load balancer layer, API gateway layer, Authentication/authorization layer