New features in 3.x

visionmedia edited this page Aug 30, 2012 · 25 revisions


  • express.application prototype
  • express.request prototype
  • express.response prototype


  • app.head() support
  • app.locals object ( = 'bar')
  • app.locals(obj) (app.locals({ foo: 'bar', bar: 'baz'}))
  • app.render(name[, options], callback) to render app-level views
  • app.engine(ext, callback) to map template engines


  • trust proxy setting enables the use of "X-Forwarded-Proto" for req.protocol and res.redirect url construction
  • json spaces setting enables the developer to decide if res.json() responds with nicely formatted JSON or compact json (this value is passed to JSON.stringify())
  • json replacer setting is a callback which is passed to JSON.stringify() in res.json() allowing you to manipulate and filter the JSON response


  • req.path the request pathname
  • req.protocol returns the protocol string "http" or "https" (supports X-Forwarded-Proto via trust proxy setting)
  • req.get(field) gets a request header field value (req.get('Host'))
  • req.accepts(type) improved
  • req.accepts(types) added, returns the most viable type
  • req.accepted array of parsed Accept values sorted by quality
  • req.acceptsCharset(charset) added
  • req.acceptedCharsets array of parsed Accept-Charset values sorted by quality
  • req.acceptsLanguage(lang) added
  • req.acceptedLanguages array of parsed Accept-Language values sorted by quality
  • req.signedCookies object containing signed cookies
  • req.stale to see if a request is stale (based on ETag/Last-Modified)
  • req.fresh to complement req.stale
  • req.ips to return an array of X-Forwarded-For values when "trust proxy" is enabled
  • req.ip return the upstream addr in req.ips or req.connection.remoteAddress
  • req.range(size) parses the Range header field


  • res.get(field) gets a response header field value (res.get('Content-Length'))
  • res.set(field, value) sets a response header field (res.set('Content-Length', n))
  • res.set(obj) set several field values
  • res.type(path) alias of previous res.contentType(path), allows res.type('json'), res.type('application/x-whatever')
  • res.format(obj) to format responses based on qvalue-sorted Accept
  • JSON cookie support (res.cookie('cart', { ids: [1,2,3] }), req.cookies.cart.ids)
  • signed cookie support (res.cookie(name, value, { signed: true }))
  • res.format(obj) for content-negotiation
  • res.locals object ( = 'bar')
  • res.locals(obj) (res.locals({ foo: 'bar', bar: 'baz'))
  • res.redirect() X-Forwarded-Proto support
  • res.redirect() relative support (res.redirect('../new'), res.redirect('./edit'), etc)
  • res.links(obj) set the "Link" header field with the given links
  • res.jsonp([status], obj) was added for explicit JSONP support