10.10. Building a Basic REST API with NodeJS and ExpressJS: In-DB Data Manipulation

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In the tenth section of our e-book course, we'll focus on creating a basic REST API with NodeJS and ExpressJS, and how to manipulate data in the database. Before we get started, it's important to understand what a REST API is. The API (Application Programming Interface) is a set of rules and protocols for building applications. REST (Representational State Transfer) is an architectural style that defines rules for creating web services. Therefore, a REST API is a programming interface that follows REST principles.

To create a basic REST API with NodeJS and ExpressJS, we need to follow a few steps. First, we need to install NodeJS and ExpressJS. NodeJS is a server-side JavaScript application development platform, while ExpressJS is a framework for NodeJS that provides useful features for web and mobile applications.

To install NodeJS, you can download it from the official website and follow the installation instructions. To install ExpressJS, you can use the npm command (Node Package Manager), which is a tool that comes with NodeJS and allows you to install JavaScript packages. The command to install ExpressJS is 'npm install express'.

Once installed, you can create a new JavaScript file, for example 'app.js', and import ExpressJS with the command 'const express = require('express')'. Then you can create an ExpressJS instance with the command 'const app = express()'. You now have an ExpressJS application that you can use to create a REST API.

To create a REST API, you need to define routes for different HTTP operations such as GET, POST, PUT and DELETE. For example, to create a GET route that returns a list of users, you can use ExpressJS's 'app.get()' method. The first argument is the path of the route, for example '/users', and the second argument is a callback function that is called when the route is accessed. The callback function takes two arguments, 'req' and 'res', which represent the HTTP request and response, respectively. You can use the 'res' object to send a response to the client.

To manipulate data in the database, you need a database module. There are many database modules available for NodeJS such as MongoDB, MySQL and PostgreSQL. For this example, we are going to use MongoDB. To install MongoDB, you can use the 'npm install mongodb' command.

Once installed, you can import MongoDB with the command 'const mongodb = require('mongodb')'. You can then create a database connection using the 'mongodb.MongoClient.connect()' method. The first argument is the database URL, and the second argument is a callback function that is called when the connection is established. The callback function takes two arguments, 'err' and 'db', which represent a possible error and the database connection, respectively.

Once you have a database connection, you can use the 'db' object to manipulate data in the database. For example, to insert a new user, you can use the 'db.collection('users').insertOne()' method. The first argument is the document to insert, and the second argument is a callback function that is called when the operation completes. The callback function takes two arguments, 'err' and 'result', which represent a possible error and the result of the operation, respectively.

We hope this guide has given you a basic introduction to building a REST API with NodeJS and ExpressJS, and manipulating data in the database. In the next chapter, we will explore more advanced features of these technologies.

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7610.11. Building a Basic REST API with NodeJS and ExpressJS: API Documentation