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Express JS-Routingmethod.pdf
- 1. EXPRESS JS-ROUTING METHODS Prepared By: Mrs. Bareen Shaikh Assistant Professor Computer Science MIT ACSC Alandi(D) Pune
- 2. Basic Routing ▪ Routing refers to determining how an application responds to a client request. ▪ Request is a URI path ,a specific HTTP request method GET, POST, etc. ▪ Example app.get('/', function (req, res) { console.log("Got a GET request for the home page"); res.send('HelloGET'); })
- 3. Basic of routing //This responds a GET request for the /list_user page. app.get('/list_user', function (req, res) { console.log("Got a GET request for /list_user"); res.send('Page Listing'); }) //This responds a GET request for abcd, abxcd, ab123cd, and so on app.get('/ab* cd', function(req, res) { console.log("Got a GET request for /ab* cd"); res.send('Page Pattern Match'); })
- 4. Url building ▪ To use the dynamic routes, we should provide different types of routes. ▪ Using dynamic routes allows us to pass parameters and process based on them. var express = require('express'); var app = express(); app.get('/:id', function(req, res){ res.send('The id you specified is ' + req.params.id); }); app.listen(3000); Give url as http://localhost:3000/4355
- 5. Url building var express = require('express'); var app = express(); app.get('/parameter/:name/:id', function(req, res){ res.send('name is '+req.params.name +' id is ' + re q.params.id); }); app.listen(3000); Give url as http://localhost:3000/parameter/bareen/4355
- 6. Serving Static files ▪ Express provides a built-in middleware to serve static files, such as images, css, JavaScript etc. express.static ▪ Pass the name of the directory,to the express.static middleware to start serving the files directly. ▪ For example, if images file in a directory named public ▪ Path as public/images/mitlogo.png ▪ app.use(express.static('public'));
- 7. Serving Static files Example var express = require('express'); var app = express(); app.use(express.static('public')); app.get('/', function (req, res) { res.send('HelloWorld'); }); var server = app.listen(3000, function () { console.log(“Server running); }); ▪ node server.js ▪ open http://localhost:3000/images/mitlogo.png
- 8. Routing Methods ▪ GET requests are used to send only limited amount of data because data is sent into header. ▪ 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.
- 9. GET Method Example(get_info.html) <html> <body> <form action="http://localhost:3000/process_get" method="GET"> First Nam e: <input type="text" name="firstname"> <br> Last Nam e: <input type="text" name="lastname"> <input type="submit" value="Submit"> </form > </body> </html>
- 10. GET Method Example(get_info.html) var express = require('express'); var app = express(); app.use(express.static('public')); app.get('/get_info.html ', function (req, res) { res.send( __dirnam e + "/" + “get_info.html " ); }) app.get('/process_get', function (req, res) { // Prepare output in JSON form at response = { first_nam e:req.query.first_name, last_nam e:req.query.last_name }; console.log(response); res.end(JSON.stringify(response)); }) var server = app.listen(3000, function () { console.log(“Server running”); })
- 11. Post Method var express = require('express'); var app = express(); var bodyParser = require('body-parser'); // Create application/x-www-form -urlencoded parser var urlencodedParser = bodyParser.urlencoded({ extended: false }) app.use(express.static('public')); app.get('/post_info.html', function (req, res) { //res.send( __dirname + "/" + "post_info.html" ); }) app.post('/process_post', urlencodedParser, function (req, res) { // Prepare output in JSON form at response = { first_name:req.body.fn, last_name:req.body.ln }; console.log(response); res.end(JSON.stringify(response)); }) var server = app.listen(3000, function () { console.log("Server running"); })