RESTful API

Using a RESTFul API in JavaScript

I have just released the third video in the JavaScript Bushido series. This video will go into what is REST and how to leverage this interface in a Qooxdoo web application.

RESTful API Logo
RESTful API Logo

The normal HTTP based request / response paradigm shifted in 2005, when Ajax ( also known as XMLHttpRequest ) became popular through the utilization in google maps.

Before Ajax every call to the back-end server would usually refresh the whole web page unless you would do some iframe based trickery.

Additionally in 2011 both WebSockets, and WebRTC have been added to most browsers which allow an efficient way to  communicate between server and browser, as well as browser to browser.

Using either method, it is possible to load data or code dynamically into the web page.

What is REST:

REST stands for “Representational State Transfer

Roy Fielding defined REST in his PhD dissertation from 2000 titled
“Architectural Styles and the Design of Network-based Software Architectures” at UC Irvine.

Unlike SOAP-based Web services, there is no “official” standard for RESTful Web APIs. This is because REST is an architectural style, while SOAP is a protocol.

A RESTFula API usually provides a means to do CRUD operations on an object.

What is CRUD:

CRUD is an acronym and stands for Create, Read, Update, and Delete. It is a way to say
“I want to be able to create, read, update, or delete something somewhere” compressed into a single word.

Before there was REST there was JSON-RPC:
REST has become a de-facto standard in modern web based applications. It has replaced the XML based SOAP/WSDL
as well as JSON-RPC.

How does a REST interface look like ?

A typical RESTful API is accessed through a well defined endpoint on a web server.
For example if you go https://jsonplaceholder.typicode.com/photos/ you will receive a JSON response which is an array of 5000 objects.

[
  {
    "albumId": 1,
    "id": 1,
    "title": "accusamus beatae ad facilis cum similique qui sunt",
    "url": "http://placehold.it/600/92c952",
    "thumbnailUrl": "http://placehold.it/150/92c952"
  },
  {
    "albumId": 1,
    "id": 2,
    "title": "reprehenderit est deserunt velit ipsam",
    ...

If you are interested in more detail about one of the returned items you would additionally provide the id https://jsonplaceholder.typicode.com/photos/7 behind the RESTful endpoint.

{
  "albumId": 1,
  "id": 7,
  "title": "officia delectus consequatur vero aut veniam explicabo molestias",
  "url": "http://placehold.it/600/b0f7cc",
  "thumbnailUrl": "http://placehold.it/150/b0f7cc"
}

But how do I create things

The sample above only showed the retrieval of datafrom a web server. But as I said before REST lets you also execute create, update, and delete operations on the backend.

This is achieved by using different HTTP VERBS

  • POST: will create an object
  • PUT: will modify / update an object
  • GET: will retrieve an object ( mostly in JSON format )
  • DELETE: will delete an object
  • OPTIONS: will provide information about the API call ( not very often used )

The best way to experiment with REST is to install POSTMAN as a plugin for chrome.

Postman in action

You can watch my video Here

And as usual you can go and play with the actual code Here …

2 thoughts on “Using a RESTFul API in JavaScript”

    1. I see,

      Thank you for pointing this out.

      you have probably not added the js after the class name.
      I.e. NewClass.js

      I fixed it such that it will be handled for you automatically.

      Please try again.

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