What is REST

Stands for Representational State Transfer

• Its a set of constraints

Why use REST

We should use it in order to mimic the Web Architecture, a model that has proben to be very successful.

Which are the REST constraints

THE CLIENT - SERVER CONSTRAINT

• Enforces a separation of concerns
• Allows independent evolution of
  • Clients
    • Like
      • browsers or others
  • Servers
    • Like
      • Apache or Nginx or others

THE STATELES CONSTRAINT

• Client-Server communication must be stateless between requests
• A request should contain all necessary data for the Server to complete it
• All session data should be returned to the client at the end of each Request
• The client side must contain all the data related to the session

THE CACHE CONSTRAINT

• Responses from the server are explicitly labeled as cacheable or non-cacheable
• Requests pass through a cache component
• The goal is to match the infrastructure of the existen Web infrastructure

THE UNIFORM CONTRACT CONSTRAINT - API

• The service and all clients must share a single uniform technical interface
• To be reusable by a wide range of clients and over a broad range of interactions
• It needs to provide generic, high-level, abstract capabilities

THE LAYERED SYSTEM CONSTRAINT

• Builds on Client-Server to allow for intermediaries / middleware
• These intermediaries must be transparent
• Information Hiding
  • Simplifies distributed architecture

REST Terminology

• Resource
  • Any sort of information that can be refert to via a URI 
• Representation
  • The current state of a resource in a specific format
  • A sequence of bytes plus representation metadata to describe those bytes
    • Like
      • XML
• Hypermedia Type
  • Specific format for a resource with aditional options
    • JSON is not Hypermedia
    • JSON plus other extra options might be a Hypermedia Type