Node Session - 3
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Express is a web application framework for Node.js that provides features for building web applications and APIs including routing, request handling, middleware support and view rendering. It allows creating single and multi-page web applications. Express makes Node.js web development fast and easy by providing features like routing, request handling, middleware support and view rendering. Common objects in Express include Request and Response objects to handle HTTP requests and responses, routing functions like GET and POST to define routes, and middleware support for operations like parsing request bodies and handling cookies.
Node Session - 3
- 1. Session III ©Techforce Infotech Pvt Ltd 2017-18
- 2. Express is a fast, assertive, essential and moderate web framework of Node.js. You can assume express as a layer built on the top of the Node.js that helps manage a server and routes. It provides a robust set of features to develop web and mobile applications. It can be used to design single-page, multi-page and hybrid web applications. It allows to setup middle wares to respond to HTTP Requests. It defines a routing table which is used to perform different actions based on HTTP method and URL. It allows to dynamically render HTML Pages based on passing arguments to templates. Installing Express:- npm install -g express Express.js
- 3. Makes Node.js web application development fast and easy. Easy to configure and customize. Node comes with support for low-overhead HTTP servers. Creating web applications using ‘http’ is a long process. Using express will give some added benefits. Allows you to create REST API server. Easy to integrate with different template engines like Jade, Vash, EJS etc. Allows you to create REST API server. Why use Express ?
- 4. Routing based on URL paths. Managing sessions via cookies. Parsing incoming request like form data or JSON. Rejecting malformed requests. Features of Express
- 6. Request :- Express.js Request objects is the parameters of the call-back function which is used in Express applications. The express.js request object represents the HTTP request and has properties for the request query string, parameters, body, HTTP headers, and so on. ex:- req.accepts('html'); Response :- The Response object (res) specifies the HTTP response which is sent by an Express app when it gets an HTTP request. It sends response back to the client browser. It facilitates you to put new cookies value and that will write to the client browser (under cross domain rule). Once you res.send() or res.redirect() or res.render(), you cannot do it again, otherwise, there will be uncaught error. Ex: - res.send({ message: 'hey' }); Express.js Objects
- 7. GET and POST Request :- GET and POST both are two common HTTP requests used for building REST API's. GET requests are used to send only limited amount of data because data is sent into header while POST requests are used to send large amount of data because data is sent in the body. Express.js facilitates you to handle GET and POST requests using the instance of express. Cookie :- Cookies are small piece of information. Ex :- var express = require('express'); var parser = require(“cookie-parser”); File Upload :- In Express.js, file upload is slightly difficult because of its asynchronous nature and networking approach. It can be done by using middleware to handle multipart/form data. There are many middleware that can be used like multer, connect, body-parser etc. Express.js Objects
- 8. Routing :- Routing is made from the word route. It is used to determine the specific behaviour of an application. It specifies how an application responds to a client request to a particular route, URI or path and a specific HTTP request method (GET, POST, etc.). It can handle different types of HTTP. Ex:- Express.js Objects app.delete('/del_student', function (req, res) { console.log("Got a DELETE request for /del_student"); res.send('Record Deleted!'); })
- 9. Session III completed Address: 403, Venus Benecia, Bodakdev,Ahmedabad – 380053 Reach us : reach@techforceinfotech.com Contact no: +91 (79) 48904529