API Design

Question 1

What REST stands for?

Answer 1

• REST stands for Representational State Transfer which is a web standards based architecture and uses HTTP Protocol for data communication.
• It revolves around resource where every component is a resource and a resource is accessed by a common interface using HTTP standard methods.
• REST uses various representations to represent a resource like text, JSON and XML. Now a days JSON is the most popular format being used in web services.

Question 2

Mention some key characteristics of REST?

Answer 2

REST is stateless, therefore the SERVER has no state (or session data)

Question 3

Explain the architectural style for creating web API?

Answer 3

• HTTP for client server communication
• XML/JSON as formatting language
• Simple URI as the address for the services
• Stateless communication

Question 4

What are resources in a REST architecture?

Answer 4

• REST architecture treats every content as a resource. These resources can be Text Files, Html Pages, Images, Videos or Dynamic Business Data. REST Server simply provides access to resources and REST client accesses and modifies the resources.

Question 5

What are advantages of REST web services?

Answer 5

• Learning curve is easy since it works on HTTP protocol
• Supports multiple technologies for data transfer such as text, xml, json, image etc.
• No contract defined between server and client, so loosely coupled implementation.
• REST methods can be tested easily over browser.

Question 6

What are the core components of a HTTP Request?

Answer 6

A HTTP Request has five major parts −

• Verb− Indicate HTTP methods such as GET, POST, DELETE, PUT etc.
• URI− Uniform Resource Identifier (URI) to identify the resource on server.
• HTTP Version− Indicate HTTP version, for example HTTP v1.1 .
• Request Header− Contains metadata for the HTTP Request message as key-value pairs. For example, client ( or browser) type, format supported by client, format of message body, cache settings etc.
• Request Body− Message content or Resource representation.

Question 7

What are the core components of a HTTP response?

Answer 7

Status / Response Code- Indicate Server status for the requested resource. For example 404 means resource not found and 200 means response is ok.

HTTP Version- Indicate HTTP version, for example HTTP v1.3

Response Header- Contains metadata for the HTTP Response message as key-value pairs. For example, content length, content type, response date, server type etc.

Response Body- Response message content or Resource representation.

Question 8

What are the best practices to create a standard URI for a web service?

Answer 8

Following are important points to be considered while designing a URI −

• Use Plural Noun− Use plural noun to define resources. For example, we’ve used users to identify users as a resource.
• Avoid using spaces− Use underscore(_) or hyphen(-) when using a long resource name, for example, use authorized_users instead of authorized%20users.
• Use lowercase letters− Although URI is case-insensitive, it is good practice to keep url in lower case letters only.
• Maintain Backward Compatibility− As Web Service is a public service, a URI once made public should always be available. In case, URI gets updated, redirect the older URI to new URI using HTTP Status code, 300.
• Use HTTP Verb− Always use HTTP Verb like GET, PUT, and DELETE to do the operations on the resource. It is not good to use operations names in URI.