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Connect is a middleware layer for Node.js


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Connect is an extensible HTTP server framework for node using "plugins" known as middleware.

var connect = require('connect')
var http = require('http')

var app = connect()

// gzip/deflate outgoing responses
var compression = require('compression')

// store session state in browser cookie
var cookieSession = require('cookie-session')
    keys: ['secret1', 'secret2']

// parse urlencoded request bodies into req.body
var bodyParser = require('body-parser')

// respond to all requests
app.use(function(req, res){
  res.end('Hello from Connect!\n');

//create node.js http server and listen on port

Getting Started

Connect is a simple framework to glue together various "middleware" to handle requests.

Install Connect

$ npm install connect

Create an app

The main component is a Connect "app". This will store all the middleware added and is, itself, a function.

var app = connect();

Use middleware

The core of Connect is "using" middleware. Middleware are added as a "stack" where incoming requests will execute each middleware one-by-one until a middleware does not call next() within it.

app.use(function middleware1(req, res, next) {
  // middleware 1
app.use(function middleware2(req, res, next) {
  // middleware 2

Mount middleware

The .use() method also takes an optional path string that is matched against the beginning of the incoming request URL. This allows for basic routing.

app.use('/foo', function fooMiddleware(req, res, next) {
  // req.url starts with "/foo"
app.use('/bar', function barMiddleware(req, res, next) {
  // req.url starts with "/bar"

Error middleware

There are special cases of "error-handling" middleware. There are middleware where the function takes exactly 4 arguments. Errors that occur in the middleware added before the error middleware will invoke this middleware when errors occur.

app.use(function onerror(err, req, res, next) {
  // an error occurred!

Create a server from the app

The last step is to actually use the Connect app in a server. The .listen() method is a convenience to start a HTTP server.

var server = app.listen(port);

The app itself is really just a function with three arguments, so it can also be handed to .createServer() in Node.js.

var server = http.createServer(app);


These middleware and libraries are officially supported by the Connect/Express team:

Most of these are exact ports of their Connect 2.x equivalents. The primary exception is cookie-session.

Some middleware previously included with Connect are no longer supported by the Connect/Express team, are replaced by an alternative module, or should be superseded by a better module. Use one of these alternatives instead:

Checkout http-framework for many other compatible middleware!

Running Tests

npm install
npm test


Node Compatibility

  • Connect < 1.x - node 0.2
  • Connect 1.x - node 0.4
  • Connect < 2.8 - node 0.6
  • Connect >= 2.8 < 3 - node 0.8
  • Connect >= 3 - node 0.10, 0.12; io.js 1.x, 2.x



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