Node js Introduction
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Node.js is an open source JavaScript runtime environment used to build real-time web applications. The document introduces Node.js, the npm package manager, the Express web application framework, and how to connect a Node.js application to MongoDB. Key points covered include Node.js being single-threaded and event-driven, using npm to install and use packages locally or globally, Express providing features for building web apps and APIs, and using modules like Mongoose to connect a Node app to MongoDB.
Node js Introduction
- 1. Node.js BUILD real time Web Application Development
- 2. Objectives Introduction to Node.js What is NPM Express framework in Node.js How to create API MongoDB Configuration At the end of the session you will be able to learn:
- 3. Introduction to node.js Node.js is an open source , cross platform runtime environment for server-side and networking applications Node.js applications are written in JavaScript, and can be run within the Node.js runtime on OS X, Microsoft Windows, Linux, etc – Wikipedia This is based on Google ‘s V8 Javascript Engine
- 4. What is Node.js It is SINGLE THREADED No Worries about : race conditions , deadlocks and other problems that go with MultiThreading. Almost no function in Node directly perform I/O, so the process never blocks. Because nothing blocks, less-than-expert programmers are able to develop scalable systems. EVENT LOOP NETWORK FILE SYSTEM PROCESS OTHER THREAD POOLEVENT QUEUE
- 5. Basics of Node.js : npm NPM stands for Node Package Manager. npm is a registry of reusable modules and packages written by various developers You can publish your own packages There are two ways to install npm packages: Locally: To use and depend on the package from your own module or project Globally: To use across the system, like a command line tool Installing a package locally: The package is easily downloaded by just running “npm install <package name>” This will create a node_modules directory (If it doesnot exist yet) and will download the package there. Once installed you can use it in any js file of your project by saying: var obj = require(‘<package name>’);
- 6. Express Framework Express is a web application framework which provides a robust set of features for web and mobile applications It is open source designed for building web application and APIs It is a server framework for Node.js It is backend part of MEAN Stack together with MongoDB, database and Angular JS frontend. Creating robust API is quick and easy It provides a thin layer of fundamental web application feature It offers a simple way to get a server up and running Features: Router Middleware Template Engine Error Handling
- 7. Express : Simple Application Example Var express = require(‘express’); Var app = express(); app.listen(9000, function(){ Console.log(‘Server listening to port 9000’); }) app.get(‘/getUsers’, function(req,res){ res.json({‘message’:’data from getUsers’}); })
- 8. Connecting MongoDB with Node.js MongoDB has rapidly grown to become a popular database for web application and is perfect fit for Node.JS applications We have lot of third party modules to connect to MongoDB Mongoose MongoDB MongoClient First we have to establish a connection between node app and MongoDB Once connection is establish, fire the query to perform a crud operation var mongoose = require(‘mongoose’); //Middleware mongoose.connect(‘mongodb://localhost:2701/userManagement’);