Connor Mills

Connor Mills

1560929029

Understanding And Using RESTful APIs

If you want to be able to read API documentations and use them effectively, you’ll first need to understand everything about RESTful APIs

Since the invention of the internet, we have been using different applications and web pages to get data for various resources. However, have you ever thought, where does this data come from? Well, it’s the servers from where we get the data. So in this article on What is REST API, let us look into how a client communicates with the servers to extract the required information.

The following topics will be covered in this article:

  • Need of REST API
  • What is REST API?
  • Principles of REST API
  • Methods of REST API
  • How to create a REST API?

Now, before I define REST API for you, let me take you through an example to make you understand the need of REST API.

Need of REST API

Consider a scenario where you are using the Book My Show app. Now, obviously, this application needs a lot of Input data, as the data present in the application is never static. Either it is movies getting released on a frequent basis, or various cities showing different languages movies at various times of the day. It’s never static which implies to the fact that data is always changing in these applications.

Now, where do you think we get this data from?

Well, this data is received from the Server or most commonly known as a Web-server. So, the client requests the server for the required information, via an API, and then, the server sends a response to the client.

Over here, the response sent to the client is in the form of an HTML Web Page. But, do you think this is an apt response that you would expect when you send a request?

Well, I am assuming the fact that you would say NO. Since, you would prefer the data to be returned in the form of structured format, rather than the complete Web page.

So, for such reasons, the data returned by the server, in response to the request of the client is either in the format of JSON or XML. Both JSON and XML format have a proper hierarchical structure of data.

Now, this sounds quite simple, right?

But, the only issue which is present in this framework till now is that you have to use a lot of methods to get the required information. To the fact, using these methods to retrieve information, becomes quite cumbersome when you require complex data.

So, this is where REST API comes into the picture. The REST API creates an object, and thereafter send the values of an object in response to the client.

Now, that you know the need of REST, next in this article, let us look into the What is REST API?

What is REST API?

REST suggests to create an object of the data requested by the client and send the values of the object in response to the user. For example, if the user is requesting for a movie in Bangalore at a certain place and time, then you can create an object on the server side.

So, over here, you have an object and you are sending the state of an object. This is why **REST **is known as Representational State Transfer.

If I have to define REST, then, * Representational State Transfer a.k.a **REST *is an architectural style as well as an approach for communications purpose that is often used in various web services development.

The architectural style of **REST **helps in leveraging the lesser use of bandwidth to make an application more suitable for the internet. It is often regarded as the “language of the internet” and is completely based on the resources.

To understand better, let’s dive a little deeper and see how exactly does a REST API work. Basically, the REST API breaks down a transaction in order to create small modules. Now, each of these modules is used to address a specific part of the transaction. This approach provides more flexibility but requires a lot of effort to be built from the very scratch.

So, now that you know what is REST API, let us next understand the constraints or principles which must be satisfied for an application to be regarded as REST API.

Principles of REST API

Well, there are six ground principles laid down by Dr. Fielding who was the one to define the REST API design in 2000. Below are the six guiding principles of REST:

Stateless

The requests sent from a client to a server will contain all the required information to make the server understand the requests sent from the client. This can be either a part of URL, query-string parameters, body, or even headers. The URL is used to uniquely identify the resource and the body holds the state of the requesting resource. Once the server processes the request, a response is sent to the client through body, status or headers

Client-Server

The client-server architecture enables a uniform interface and separates clients from the servers. This enhances the portability across multiple platforms as well as the scalability of the server components.

Uniform Interface

To obtain the uniformity throughout the application, REST has the following four interface constraints:
Resource identificationResource Manipulation using representationsSelf-descriptive messagesHypermedia as the engine of application state### Cacheable

In order to provide a better performance, the applications are often made cacheable. This is done by labeling the response from the server as cacheable or non-cacheable either implicitly or explicitly. If the response is defined as cacheable, then the client cache can reuse the response data for equivalent responses in the future.

Layered system

The layered system architecture allows an application to be more stable by limiting component behavior. This type of architecture helps in enhancing the application’s security as components in each layer cannot interact beyond the next immediate layer they are in. Also, it enables load balancing and provides shared caches for promoting scalability.

Code on demand

This is an optional constraint and is used the least. It permits a clients code or applets to be downloaded and to be used within the application. In essence, it simplifies the clients by creating a smart application which doesn’t rely on its own code structure.

Now, that you know the principles behind REST API, next let’s look into the Methods of REST API.

Methods of REST API

All of us working with the technology of the web, do CRUD operations. When I say CRUD operations, I mean that we create a resource, read a resource, update a resource and delete a resource. Now, to do these actions, you can actually use the HTTP methods, which are nothing but the REST API Methods. Refer below.

Now that you know what is a REST API and what all you need to mind in order to deliver an efficient application, let’s dive deeper and see the process of building REST API.

How to create a REST API?

In this practical demonstration, I will be creating a simple CRUD REST application using Node.js. To build this application, you will need to install the following:
Node.jsExpress.jsJoinodemon (Node Monitor)
For this hands-on, I will be using the WebStorm IDE to write and execute the codes. You can use any IDE or code editor according to your choice. So, let’s get started.

Step 1: Create a project directory, which will consist of all the files present in the project. Then, open commands prompt and navigate to the project directory. Refer below.

Step 2: Now, call npm using the below command. This will initialize the npm modules in your system.

npm init

Once you hit enter, Node.js, will ask you to enter a few details related to the project. These details will basically be the metadata for your project. Refer below.

Here you can define your entry point along with several other information. For this demo, I will be using script.js as an entry point.

It will then, ask you for a confirmation for the data you must have mentioned. Just press on** Y** to confirm. Refer below.

**Step 3: **Next, you have yo install Express.js using the below command:

npm i express

Express is a web framework which can be used along with Node.js. This web framework will allow you to create Restful APIs, with the help of helper methods, middle layers to configure your application.

Step 3.1: Similarly, you have to install Joi.

npm i joi

This package allows you to create blueprints for JavaScript objects which store information to ensure validation of key information.

Step 3.2: Finally, install the node monitoring package nodemon, using the below command.

npm i -g nodemon

Nodemon, keeps a watch on all the files with any type of extension present in this folder. Also, with nodemon on the watch, you don’t have to restart the Node.js server each time any changes are made. Nodemon will implicitly detect the changes and restart the server for you.

package.json

{
"name": "restapidemo",
"version": "1.0.0",
"description": "Creation of REST API",
"main": "script.js",
"scripts": {
"test": "echo \"Error: no test specified\" && exit 1"
},
"author": "sahiti_kappagantula",
"license": "ISC",
"dependencies": {
"express": "^4.17.1",
"joi": "^14.3.1"
}
}

script.js

const express = require('express'); //Import Express
const Joi = require('joi'); //Import Joi
const app = express(); //Create Express Application on the app variable
app.use(express.json()); //used the json file
 
//Give data to the server
const customers = [
{title: 'George', id: 1},
{title: 'Josh', id: 2},
{title: 'Tyler', id: 3},
{title: 'Alice', id: 4},
{title: 'Candice', id: 5}
]
 
//Read Request Handlers
// Display the Message when the URL consist of '/'
app.get('/', (req, res) => {
res.send('Welcome to Edurekas REST API!');
});
// Display the List Of Customers when URL consists of api customers
app.get('/api/customers', (req,res)=> {
res.send(customers);
});
// Display the Information Of Specific Customer when you mention the id.
app.get('/api/customers/:id', (req, res) => {
const customer = customers.find(c => c.id === parseInt(req.params.id));
//If there is no valid customer ID, then display an error with the following message
if (!customer) res.status(404).send('<h2 style="font-family: Malgun Gothic; color: darkred;">Ooops... Cant find what you are looking for!</h2>');
res.send(customer);
});
 
//CREATE Request Handler
//CREATE New Customer Information
app.post('/api/customers', (req, res)=> {
 
const { error } = validateCustomer(req.body);
if (error){
res.status(400).send(error.details[0].message)
return;
}
//Increment the customer id
const customer = {
id: customers.length + 1,
title: req.body.title
};
customers.push(customer);
res.send(customer);
});
 
//Update Request Handler
// Update Existing Customer Information
app.put('/api/customers/:id', (req, res) => {
const customer = customers.find(c=> c.id === parseInt(req.params.id));
if (!customer) res.status(404).send('<h2 style="font-family: Malgun Gothic; color: darkred;">Not Found!! </h2>');
 
const { error } = validateCustomer(req.body);
if (error){
res.status(400).send(error.details[0].message);
return;
}
 
customer.title = req.body.title;
res.send(customer);
});
 
//Delete Request Handler
// Delete Customer Details
app.delete('/api/customers/:id', (req, res) => {
 
const customer = customers.find( c=> c.id === parseInt(req.params.id));
if(!customer) res.status(404).send('<h2 style="font-family: Malgun Gothic; color: darkred;"> Not Found!! </h2>');
 
const index = customers.indexOf(customer);
customers.splice(index,1);
 
res.send(customer);
});
//Validate Information
function validateCustomer(customer) {
const schema = {
title: Joi.string().min(3).required()
};
return Joi.validate(customer, schema);
 
}
 
//PORT ENVIRONMENT VARIABLE
const port = process.env.PORT || 8080;
app.listen(port, () => console.log(`Listening on port ${port}..`));

Step 4: Now, the next step is to check whether the handlers are working properly or not. For that, we will use a Chrome extension called Postman. To install Postman you can visit here** **and click on ‘Add to Chrome’.

Step 5: Now, once you have installed Postman, open it to test your application.

Step 6: But before that you have to start your server. To start your server, type the following command.

node script.js

You would see the output as below:

Results

Let us start by testing the GET Method.

Step 7: In order to do that you need to select GET from the drop-down list, type in the defined URL and hit send.

If your code is working fine, then you will see the list of all the customers which we have added manually in our code. In the below picture, you can see how my result looks like. Here I have mentioned the URL to be localhost:8080/api/customers

Step 8: Now, let’s try adding a new customer to our stack of customers. For that, select ‘POST’ from the drop-down list and type in the defined URL for the POST method. Then, click on ‘Body’, select ‘raw’ and move on to select ‘JSON’ from the drop-down list as depicted in the below image. Now,** in the text area,** type in the name of your customer as shown and hit send.

If your POST method is working fine, your response body will contain the new customer’s name along with the Customer ID. Here if you observe, we have only mentioned the name but we did not give the customer ID. This implies that the Customer ID is automatically incremented

Step 9: Now, let’s try to update a Customer name. Let us say we ant to update the name of the Customer ID = 3. So, to update the data, you need to first select ‘PUT’ from the drop-down table and enter the PUT request’s URL along with the customer id you wish to update. Next in the ‘Body’, type in the new customer name and hit enter.

This will give you a response with the customer id and updated customer name.

Step 10: Finally, let’s send a ‘DELETE’ request to delete an existing record. For that select DELETE from the drop-down list and type in the URL of the delete request handler along with the customer’s details, you want to remove and hit enter. Let’s say, I want to delete the details of a customer with id = 3. If your transaction is successful, you will see the complete details of the entry you have removed in the response body.

Now, let’s send a GET request for our final list of customers.

As you can see from the above screenshot, the response body contains a total of five customers with the customer id 3 missing as we have already deleted that entry.

#rest #api #web-development #web-service #node-js

What is GEEK

Buddha Community

Understanding And Using RESTful APIs
Wilford  Pagac

Wilford Pagac

1594289280

What is REST API? An Overview | Liquid Web

What is REST?

The REST acronym is defined as a “REpresentational State Transfer” and is designed to take advantage of existing HTTP protocols when used for Web APIs. It is very flexible in that it is not tied to resources or methods and has the ability to handle different calls and data formats. Because REST API is not constrained to an XML format like SOAP, it can return multiple other formats depending on what is needed. If a service adheres to this style, it is considered a “RESTful” application. REST allows components to access and manage functions within another application.

REST was initially defined in a dissertation by Roy Fielding’s twenty years ago. He proposed these standards as an alternative to SOAP (The Simple Object Access Protocol is a simple standard for accessing objects and exchanging structured messages within a distributed computing environment). REST (or RESTful) defines the general rules used to regulate the interactions between web apps utilizing the HTTP protocol for CRUD (create, retrieve, update, delete) operations.

What is an API?

An API (or Application Programming Interface) provides a method of interaction between two systems.

What is a RESTful API?

A RESTful API (or application program interface) uses HTTP requests to GET, PUT, POST, and DELETE data following the REST standards. This allows two pieces of software to communicate with each other. In essence, REST API is a set of remote calls using standard methods to return data in a specific format.

The systems that interact in this manner can be very different. Each app may use a unique programming language, operating system, database, etc. So, how do we create a system that can easily communicate and understand other apps?? This is where the Rest API is used as an interaction system.

When using a RESTful API, we should determine in advance what resources we want to expose to the outside world. Typically, the RESTful API service is implemented, keeping the following ideas in mind:

  • Format: There should be no restrictions on the data exchange format
  • Implementation: REST is based entirely on HTTP
  • Service Definition: Because REST is very flexible, API can be modified to ensure the application understands the request/response format.
  • The RESTful API focuses on resources and how efficiently you perform operations with it using HTTP.

The features of the REST API design style state:

  • Each entity must have a unique identifier.
  • Standard methods should be used to read and modify data.
  • It should provide support for different types of resources.
  • The interactions should be stateless.

For REST to fit this model, we must adhere to the following rules:

  • Client-Server Architecture: The interface is separate from the server-side data repository. This affords flexibility and the development of components independently of each other.
  • Detachment: The client connections are not stored on the server between requests.
  • Cacheability: It must be explicitly stated whether the client can store responses.
  • Multi-level: The API should work whether it interacts directly with a server or through an additional layer, like a load balancer.

#tutorials #api #application #application programming interface #crud #http #json #programming #protocols #representational state transfer #rest #rest api #rest api graphql #rest api json #rest api xml #restful #soap #xml #yaml

An API-First Approach For Designing Restful APIs | Hacker Noon

I’ve been working with Restful APIs for some time now and one thing that I love to do is to talk about APIs.

So, today I will show you how to build an API using the API-First approach and Design First with OpenAPI Specification.

First thing first, if you don’t know what’s an API-First approach means, it would be nice you stop reading this and check the blog post that I wrote to the Farfetchs blog where I explain everything that you need to know to start an API using API-First.

Preparing the ground

Before you get your hands dirty, let’s prepare the ground and understand the use case that will be developed.

Tools

If you desire to reproduce the examples that will be shown here, you will need some of those items below.

  • NodeJS
  • OpenAPI Specification
  • Text Editor (I’ll use VSCode)
  • Command Line

Use Case

To keep easy to understand, let’s use the Todo List App, it is a very common concept beyond the software development community.

#api #rest-api #openai #api-first-development #api-design #apis #restful-apis #restful-api

REST API In Laravel Example

Hello Friends,

Today I will give you information about REST API, REST API is an application program interface that uses HTTP requests to GET, PUT, POST and DELETE data.

In this tutorial I am going to perform CRUD operation using REST API and you can learn how to create REST API with authentication using passport in laravel 6/7 application. here we will get data from API.

REST API In Laravel Example

https://websolutionstuff.com/post/rest-api-in-laravel

#rest api in laravel example #php #rest api #crud operation using rest api #rest api with passport #laravel rest api crud

Adonis  Kerluke

Adonis Kerluke

1596509565

RESTful API Design Driven Approach

In this tutorial I will show you the fundamentals of designing a RESTful API specification by applying REST principles and best practices, then you’ll be ready to try my online tutorial: How to design a REST API with API Designer?

If you already know what is meant by API in the context of RESTful web services, you can skip to the next section. If not, read on.

Level-Set on API

The abbreviation API stands for Application Programming Interface this in itself, does not help us understand what it is, however in the context of web services, it can refer to one of two things:

  1. The RESTful API specification is written using a modeling language such as Open API specification or RAML (RESTful API Modeling Language) that defines a contract for how software components can interact with a service.
  2. The implementation of a web service or microservice whose contract is designed by REST principles that describe how other services must interact with it.

In this post, I will use the first understanding of this term. Even though both are correct, the most technically relevant for this post is the first: an API is a contract for how software applications talk to each other.

Level-Set on REST

The acronym REST stands for REpresentational State Transfer. It is an architectural style used to represent the transmission of data from one application component to another. In the context of web services, we are talking about the representation of resources (i.e. data) transferred over HTTP by calling a URI that represents the data and via an HTTP method that represents the action to perform against the given data.

What Is RESTful API design?

RESTful API design is the activity of describing the behavior of a web service in terms of its data structures and the actions you allow other application components to perform on its data by the principles of REST. Those principles are covered later in this blog.

Why Design a RESTful API?

Imagine that you are an Architect (the kind the design building) and you set out to build an office block without a blueprint. You turn up on the first day with a truck full of bricks and some cement. What are the chances that you’ll be successful and build a structure that conforms to code and more importantly, doesn’t fall? It’s about zero. Without a blueprint the chance of failure is high.

The same approach applies to web service development. You need a blueprint, or more appropriately, an API specification. This is necessary to evaluate the API design and solicit feedback before even starting to build the implementation.

In addition to providing a specification for the web service’s development, an API contract serves to document its expected behavior, data types, and security requirements.

You should now be satisfied that API design is necessary for a RESTful web service, and should start to wonder how is the best approach to actually designing an API specification.

API Design Tooling

The tooling chosen by an API designer has substantial influence over the designer’s productivity. Highly productive tools such as the Anypoint API Designer from MuleSoft is perfect for designing APIs with OAS (swagger) or RAML.

#integration #api #rest #rest api #restful #api design #raml #rest api design