A Short Introduction to HTTP Requests (REST API)

In the recent times, The term “REST API” is commonly and widely used word across in IT workspaces as well in IT related blogs and vlogs.
So What is REST?… Well, if you want to know what it is?.. Then this post is for U…….

REST

REST stands for REPRESENTATIONAL STATE TRANSFER

When a RESTful API (API that satifies REST Architecture) is called, the server will transfer a representation of state of the requested resource to the client.

The respresentation of the state can be in any format JSON, XML, HTML. Most widely used is JSON (JavaScript Object Notation)

• REST is an architecture or design pattern for API’s
• REST is merely a protocol for API to work on.
• REST is preferred over SOAP because it is simple, flexible and uses less bandwidth making it suitable for internet usage (Speed Matters)
• REST communicates via HTTP request only. (Now you can get why this post title is given as HTTP request)
• REST commonly used to give or fetch some information from a web services.
• REST is a Client – Server architecture.
• REST is stateless.

How REST works?

Whenever a client sends the request, the request will be sent to the server. And then the server will returns the response for the sent request as the HTTP response message.

Widely used HTTP methods

GET – This method is used to retrieve the information from the resource.
POST – This is used to create resources.
PUT – This is used to updating the capability in the resources. This can be also used to create resource (But not recommended).
DELETE – This is used to delete a resources.
PATCH – This is used to modify the capability in the resources. Only the changes alone needs to be sent in the request.

GET Request Method

“GET” method is commonly used HTTP method to retrieve/request/get the particular information from server.

Lets see an example of a basic HTTP GET request

require “net/http”

response =  Net::HTTP.get_response("api.themoviedb.org","/3/movie/popular?api_key=1f6edcf7cdec1a1942d5d87e84a1ab89")
puts (response)

Note: We are using an library “net/http” which handles all HTTP request operations

output:
     #<Net::HTTPOK 200 OK readbody=true>

Points to noted:

Here the response variable will be a object.
With reponse object , other details can be extracted.

    Example
    response.code  # returns response code
    response.body  # returns body of the response 
    response.content_type # returns content type of the reponse body

Above output will be received when the above piece of code gets executed.

What happens after “Net::HTTP.get_response” is called?

Whenever a request is sent, it will be sent to the server from client as a request message, which is received by the server and returns the response via response message.

Request Message

Whenever a request is initiated, the requested URL will be divided in to 3 parts

• Request Line
• Request Header
• Request Message Body

Request Line – GET /3/movie/popular?api_key=1f6edcf7cdec1a1942d5d87e84a1ab89 HTTP/1.1

In above used example, GET is the method we used and the contents after host will be sent in the header
The client uses the optional request headers (such as Accept, Accept-Language, and etc) to negotiate with the server and ask the server to deliver the preferred contents (e.g., in the language that the client preferred).

Request Header – api.themoviedb.org
In the request header host name will sent

Request Message Body – Optional
Message body is optional, Here request can be sent to get the exact information or only needed details.

Response Message

The received response can be divided in to 3 parts

• Status Line
• Response Headers
• Response Body

Status Line
Status line will contains the status of the request
HTTPOK 200 OK

Response Header
This will get the details about the response such as content type of the response and other details that is sent by the server.

require “net/http”

response =  Net::HTTP.get_response("api.themoviedb.org","/3/movie/popular?api_key=1f6edcf7cdec1a1942d5d87e84a1ab89")
puts(response.content_type)

    Output:
    application/json

The above part of code will give the output of the reponse content type which is one of content in response header.

Response Body
This will have the information above the contents of the response such as JSON, XML, HTML.

Bubye !!! This is the end of this post. In next post, Lets discuss on POST request method.

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