Express.js
January 21st, 2015
NODE.JS
-
Fast (built on top of Google's V8 engine)
- Allows for one language throughout the entire stack
- The npm (node package manager) is fairly robust and has some great packages
-
Basically "javascript running on the server"
EXPRESS.JS
-
A web application framework that provides
-
Route handling
-
Middleware
-
HTTP Request
- GET - Read
- POST - Create
- PUT - Update
- DELETE - Delete
Client sends an HTTP request to the web server
Client
(Users)
Server
(express.js)
Request
Response
1
GET /
Express handles request
Client
(Users)
Server
(express.js)
Request
Response
Static Content
HTML
IMG
CSS
JS
DB
2
Sends response to Client
Client
(Users)
Server
(express.js)
Request
Response
Static Content
HTML
IMG
CSS
JS
DB
3
Quick code sample
var express = require ('express');
var app = express();
app.get('/', function (req, res) {
res.send('hello world');
});
app.listen(3000);GETTING STARTED
expressjs.com
First, create a directory to hold your application
$ mkdir myapp
$ cd myapp
Create a package.json file
$ npm init
Install Express in the app directory and save it in the dependencies list
$ npm install express --saveINSTALLING
app.js
$ touch app.jsvar express = require('express');
var app = express();
app.get('/', function (req, res) {
res.send('Hello World!');
});
app.listen(3000);The app starts a server and listens on port 3000 for connection. It will respond with "Hello World!" for request to the homepage.
Hello world example
"Hello world!"
Save the code in file named app.js and run it with the following command
$ node app.jsThen, load http://localhost:3000/ in the browser to see the output
Basic routing tutorial
Routing is determined by how the application responds to a client request on a HTTP request method (GET, POST, DELETE, PUT)
Each route has a handler function, executed when the route is matched
app.post('/', function (req, res) {
res.send('Got a POST request');
});The following code illustrates some example routes in an app
//respond with "Hello World!" on the homepage
app.get('/', function (req, res) {
res.send('Hello World!');
});
//accept POST request on the homepage
app.post('/', function (req, res) {
res.send('Got a POST request');
});
//accept PUT request at /user
app.put('/user', function (req, res) {
res.send('Got a PUT request at /user');
});
//accept DELETE request at /user
app.delete('/user', function (req, res) {
res.send('Got a DELETE request at /user');
});Middleware
- Make changes to the request and the response objects
- Call the next middleware in the stack
Request
Step 1
Request
Step 2
Request
Step 3
Response
Authenticate
(Passport)
Get User Information (DB)
Compile HTML File
(Render JADE Template)
Redirect
('/login');
500
Error
Middleware
next()
next()
JADE TEMPLATES
$ npm install jade --save
var express = require('express');
var app = express();
var path = require('path');
app.set('views', path.join(__dirname, 'views'));
app.set ('view engine', 'jade');
app.get('/', function (req, res) {
res.render('index');
});
app.listen(3000);
Install Jade in the app directory and save it in the dependencies list
Comment out old example and implement the code below
Jade Template Example
$ mkdir views
$ cd views$ touch index.jadeFirst, create a directory to hold your application
Create a file
"Hello, my name is Jade!"
h1
| Hello, my name is Jade!Save the code in file named app.js and run it with the following command
$ cd ..
$ node app.jsThen, load http://localhost:3000
in the browser to see the output
Create a h1 in the JADE file
Thank you!
Copy of Express.js
By eunjoolee787
Copy of Express.js
- 720
