REST - Wendy's 4 for 4

Within these castle walls be forged Mavens of Computer Science ...

— Merlin, The Coder

Brief Overview[edit]

API in action

REST API or RESTful API stands for REpresentational State Transfer

An API is a means of communication with a server. Whenever you browse something on the internet, your browser will ask the server for data. The server will then present the data; an API handles the data transfer between your device and the server.

The rest API works with the client and server. The client will send data through a request, and the server will send the data back in the form of a response.

To view, an image of how RESTAPI works click here[[1]]

Components[edit]

Resource Path

Resource path is the “request target” or the desired destination for the object. For example, a resource path could be “codermerlin.com/wiki/database/grades” where the object would be sent to the grades directory of the host.

HTTP Verb

With an HTTP Verb, the actions of the resource could be easily defined. A handy acronym to remember the available HTTP Verbs is “C R U D” or Creation (creates a resource), Retrieval (retrieves a resource), Update (updates a resource), and Deletion (deletes a resource).

Body

The body is the contents of the resource, and conveniently uses the JSON (JavaScript Object Notation) as the format. Both Creation operations and Update operations contain a body, but a Retrieval operation does not contain a body. In addition, the Deletion operation would also not contain a body.

Header

A header in short is simply a description of the resource, essentially acting as metadata for the resource.

Usage[edit]

REST has become increasingly popular due to its data structure requiring less bandwidth (Maximum amount of data transferred over time), making it much more efficient at transferring data. As a result, REST is often used on many web services and more recently, cloud services.

Additional Concepts & Challenges[edit]

Restrictions[edit]

Uniform interface

All resources should be obtained by using a common method such as HTTP GET and similarly manipulated using a common approach.

Client–server

Client application and server application must be able to function separately and the client should know only the resource URL.

Stateless

The server will not keep the latest HTTP request the client made. Every request will be given equal importance or in other words be “new”.

Cacheable

Caching shall be applied to resources when acceptable, and then these resources must call themselves cacheable to avoid extra client-server interactions, and using caching, in general, can eliminate client-server interactions, improving scalability and performance.

Layered system

REST uses a layered system architecture where you assign the APIs on server A, and store data on server B, and complete requests in Server C for example.

Code on demand (optional)

Clients may use your API to get a UI widget rendering code that can be rendered directly in the code of MVC views.