RESTful API in Node.js

What is REST architecture?

REST stands for Representational State Tranfer. REST is a web standard based on basic architectures using HTTP protocol. It processes resources, where each component is a resource and this resource can be accessed through common interfaces using standard HTTP methods. REST was first introduced by Roy Fielding in 2000.

Basically, a REST Server provides access to resources and REST Client access and modification of these resources using the HTTP method. Here each resource is identified by a URI. REST uses various representations to represent resources such as text, JSON, and XML, but the most common is JSON.

HTTP method used in REST

Here are the HTTP methods widely used in REST architecture.

GET - Used only to read resources.

PUT - Used to create new resources.

DELETE - Used to delete resources.

POST - Used to update the current record and create new resources.

RESTful Web Service

A web service is a set of protocols and standards used for the purpose of exchanging applications and systems. Software applications written in different languages ​​and run by different platforms can use web service to exchange data over computer networks such as the internet in the same way as exchanging on a computer. .

Web services based on REST architectures are known as RESTful webservice. These webservices use the HTTP method to deploy REST architecture definitions. A RESTful web service is usually defined as a URI (like path), Uniform Resource Identifier as a service.

Create RESTful for a library

Suppose we have a JSON-based database containing information about User, the file name is users.json:

 { "user1" : { "name" : "huong", "password" : "password1", "profession" : "sinhvien", "id": 1 }, "user2" : { "name" : "manh", "password" : "password2", "profession" : "giangvien", "id": 2 }, "user3" : { "name" : "tuyen", "password" : "password3", "profession" : "laptrinhvien", "id": 3 } } 

Based on this basic information, we will provide the following RESTful APIs:

List Users

We together deploy the first RESTful API named listUsers by using the following code:

 var express = require ( 'express' ); var app = express (); var fs = require ( "fs" ); app . get ( '/listUsers' , function ( req , res ) { fs . readFile ( __dirname + "/" + "users.json" , 'utf8' , function ( err , data ) { console . log ( data ); res . end ( data ); }); }) var server = app . listen ( 8081 , function () { var host = server . address (). address var port = server . address (). port console . log ( "Ung dung Node.js dang lang nghe tai dia chi: http://%s:%s" , host , port ) }) 

Now try accessing the API defined above using http://127.0.0.1:8081/listUsers on the local computer. It will produce the following results:

 { "user1" : { "name" : "huong" , "password" : "password1" , "profession" : "sinhvien" , "id" : 1 }, "user2" : { "name" : "manh" , "password" : "password2" , "profession" : "giangvien" , "id" : 2 }, "user3" : { "name" : "tuyen" , "password" : "password3" , "profession" : "laptrinhvien" , "id" : 3 } } 

Add a new User

The following API shows how to add a new User to the list. Below is the information of the new User:

 user = { "user4" : { "name" : "hoang" , "password" : "password4" , "profession" : "sinhvien" , "id" : 4 } } 

You can use Ajax to do this, but for simplicity we will hard code here. Below is the addUser API method to add a new user in the database.

 var express = require ( 'express' ); var app = express (); var fs = require ( "fs" ); var user = { "user4" : { "name" : "hoang" , "password" : "password4" , "profession" : "sinhvien" , "id" : 4 } } app . get ( '/addUser' , function ( req , res ) { // Dau tien, doc tat ca cac User dang ton tai. fs . readFile ( __dirname + "/" + "users.json" , 'utf8' , function ( err , data ) { data = JSON . parse ( data ); data [ "user4" ] = user [ "user4" ]; console . log ( data ); res . end ( JSON . stringify ( data )); }); }) var server = app . listen ( 8081 , function () { var host = server . address (). address var port = server . address (). port console . log ( "Ung dung Node.js dang lang nghe tai dia chi: http://%s:%s" , host , port ) }) 

Now try accessing the API above using http://127.0.0.1:8081/addUsers on the local computer. The results will be displayed as follows:

 { user1 : { name : 'huong' , password : 'password1' , profession : 'sinhvien' , id : 1 }, user2 : { name : 'manh' , password : 'password2' , profession : 'giangvien' , id : 2 }, user3 : { name : 'tuyen' , password : 'password3' , profession : 'laptrinhvien' , id : 3 }, user4 : { name : 'hoang' , password : 'password4' , profession : 'sinhvien' , id : 4 } } 

Display User information

Now deploy an API that calls the userID to display the corresponding User information.

 var express = require ( 'express' ); var app = express (); var fs = require ( "fs" ); app . get ( '/:id' , function ( req , res ) { // Dau tien, doc tat ca cac User dang ton tai. fs . readFile ( __dirname + "/" + "users.json" , 'utf8' , function ( err , data ) { users = JSON . parse ( data ); var user = users [ "user" + req . params . id ] console . log ( user ); res . end ( JSON . stringify ( user )); }); }) var server = app . listen ( 8081 , function () { var host = server . address (). address var port = server . address (). port console . log ( "Ung dung Node.js dang lang nghe tai dia chi: http://%s:%s" , host , port ) }) 

Next, you call the service on using the address http://127.0.0.1:8081/2 on the local computer. The result will be as follows:

 { 
 "name": "manh", 
 "password": "password2", 
 "profession": "giangvien", 
 "id": 2 
 } 

Delete User

This API is similar to addUser API, where you can get an input through req.body and then rely on the userID to delete that User from the Database. For simplicity, suppose we delete the user whose ID is 2.

 var express = require ( 'express' ); var app = express (); var fs = require ( "fs" ); var id = 2 ; app . get ( '/deleteUser' , function ( req , res ) { // Dau tien, doc tat ca cac User dang ton tai. fs . readFile ( __dirname + "/" + "users.json" , 'utf8' , function ( err , data ) { data = JSON . parse ( data ); delete data [ "user" + 2 ]; console . log ( data ); res . end ( JSON . stringify ( data )); }); }) var server = app . listen ( 8081 , function () { var host = server . address (). address var port = server . address (). port console . log ( "Ung dung Node.js dang lang nghe tai dia chi: http://%s:%s" , host , port ) }) 

Call the above service using http://127.0.0.1:8081/deleteUser on the local computer. It will produce the following results:

 {user1: 
 { name: 'huong', {name: 'huong', 
 password: 'password1', password: 'password1', 
 profession: 'sinhvien', profession: 'sinhvien', 
 id: 1 }, id: 1}, 
 user3: 
 {name: 'tuyen', 
 password: 'password3', password: 'password3', 
 profession: 'laptrinhvien', profession: 'laptrinhvien', 
 id: 3 } id: 3} 
 } 

According to Tutorialspoint

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