Switch branches/tags
Nothing to show
Find file History
Fetching latest commit…
Cannot retrieve the latest commit at this time.
Permalink
Type Name Latest commit message Commit time
..
Failed to load latest commit information.
express-cover.png add changes 🚂 Jun 17, 2016
readme.md Use github URL for express cors package Jun 20, 2017

readme.md

Express.js 4 Cheatsheet

These people are the Sparta’s walls.

Beautifully-designed print-ready PDF

Installation

  • $ sudo npm install express: install the latest Express.js locally
  • $ sudo npm install express@4.2.0 --save: install Express.js v4.2.0 locally and save to package.json
  • $ sudo npm install -g express-generator@4.0.0: install Express.js command-line generator v4.0.0

Generator

Usage: $ express [options] [dir]

Options:

  • -h: print the usage information
  • -V: print the express-generator version number
  • -e: add ejs engine support, defaults to jade if omitted
  • -H: add hogan.js engine support
  • -c <library> add CSS support for (less|stylus|compass), defaults to plain CSS if omitted
  • -f: generate into a non-empty directory

Basics

  • var express = require('express'): include the module
  • var app = express(): create an instance
  • app.listen(portNumber, callback): start the Express.js server
  • http.createServer(app).listen(portNumber, callback): start the Express.js server
  • app.set(key, value): set a property value by the key
  • app.get(key): get a property value by the key

HTTP Verbs and Routes

  • app.get(urlPattern, requestHandler[, requestHandler2, ...])
  • app.post(urlPattern, requestHandler[, requestHandler2, ...])
  • app.put(urlPattern, requestHandler[, requestHandler2, ...])
  • app.delete(urlPattern, requestHandler[, requestHandler2, ...])
  • app.all(urlPattern, requestHandler[, requestHandler2, ...])
  • app.param([name,] callback):
  • app.use([urlPattern,] requestHandler[, requestHandler2, ...])

Request

  • request.params: parameters middlware
  • request.param: extract one parameter
  • request.query: extract query string parameter
  • request.route: return route string
  • request.cookies: cookies, requires cookie-parser
  • request.signedCookies: signed cookies, requires cookie-parser
  • request.body: payload, requires body-parser

Request Header Shortcuts

  • request.get(headerKey): value for the header key
  • request.accepts(type): checks if the type is accepted
  • request.acceptsLanguage(language): checks language
  • request.acceptsCharset(charset): checks charset
  • request.is(type): checks the type
  • request.ip: IP address
  • request.ips: IP addresses (with trust-proxy on)
  • request.path: URL path
  • request.host: host without port number
  • request.fresh: checks freshness
  • request.stale: checks staleness
  • request.xhr: true for AJAX-y requests
  • request.protocol: returns HTTP protocol
  • request.secure: checks if protocol is https
  • request.subdomains: array of subdomains
  • request.originalUrl: original URL

Response

  • response.redirect(status, url): redirect request
  • response.send(status, data): send response
  • response.json(status, data): send JSON and force proper headers
  • response.sendfile(path, options, callback): send a file
  • response.render(templateName, locals, callback): render a template
  • response.locals: pass data to template

Handlers Signatures

  • function(request, response, next) {}: request handler signature
  • function(error, request, response, next) {}: error handler signature

Stylus and Jade

app.set('views', path.join(__dirname, 'views'))
app.set('view engine', 'jade')

app.use(require('stylus').middleware(path.join(__dirname, 'public')))

Body

var bodyParser = require('body-parser')
app.use(bodyParser.json())
app.use(bodyParser.urlencoded({
    extended: true
}))

Static

app.use(express.static(path.join(__dirname, 'public')))

Connect Middleware

$ sudo npm install <package_name> --save

Other Popular Middleware