What is connect?
The connect npm package is a middleware layer for Node.js, designed to be used as a part of the 'http' module. It allows developers to create a series of middleware functions to handle requests and responses in a sequential manner. Connect is often used to set up middleware that can perform various tasks such as logging, parsing, session handling, and more.
What are connect's main functionalities?
Logging
This feature allows you to log every request that comes into the server with the method and URL.
const connect = require('connect');
const app = connect();
// Middleware for logging
function logger(req, res, next) {
console.log('%s %s', req.method, req.url);
next();
}
app.use(logger);
app.listen(3000);
Static File Serving
This feature serves static files from a specified directory, in this case, 'public'.
const connect = require('connect');
const serveStatic = require('serve-static');
const app = connect();
app.use(serveStatic('public'));
app.listen(3000);
Body Parsing
This feature allows you to parse the body of incoming requests in middleware before handling them.
const connect = require('connect');
const bodyParser = require('body-parser');
const app = connect();
app.use(bodyParser.json());
app.use(function(req, res) {
res.end(JSON.stringify(req.body));
});
app.listen(3000);
Cookie Parsing
This feature allows you to parse cookies attached to the client request object.
const connect = require('connect');
const cookieParser = require('cookie-parser');
const app = connect();
app.use(cookieParser());
app.use(function(req, res) {
res.end(JSON.stringify(req.cookies));
});
app.listen(3000);
Other packages similar to connect
express
Express is a web application framework for Node.js, built on top of connect. It extends connect's middleware model with additional functionality like routing, template engine support, and more. Express is more feature-rich and is considered a de facto standard for Node.js web applications.
koa
Koa is a web framework designed by the creators of Express, aiming to be a smaller, more expressive, and more robust foundation for web applications and APIs. Koa uses async functions to eliminate callbacks and greatly increase error-handling capabilities. It does not bundle any middleware within its core, and it provides an elegant suite of methods that make writing servers fast and enjoyable.
hapi
Hapi is a rich framework for building applications and services. It enables developers to focus on writing reusable application logic instead of spending time building infrastructure. Hapi is known for its powerful plugin system and comprehensive API.
restify
Restify is a Node.js web service framework optimized for building semantically correct RESTful web services ready for production use at scale. It is somewhat similar to Express but is more focused on enabling the building of correct REST web services.
Connect
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()
var compression = require('compression')
app.use(compression())
var cookieSession = require('cookie-session')
app.use(cookieSession({
keys: ['secret1', 'secret2']
}))
var bodyParser = require('body-parser')
app.use(bodyParser.urlencoded())
app.use(function(req, res){
res.end('Hello from Connect!\n');
})
http.createServer(app).listen(3000)
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) {
next();
});
app.use(function middleware2(req, res, next) {
next();
});
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) {
next();
});
app.use('/bar', function barMiddleware(req, res, next) {
next();
});
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) {
});
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);
Middleware
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:
cookieParser
limit
multipart
query
staticCache
Checkout http-framework for many other compatible middleware!
Running Tests
npm install
npm test
Contributors
https://github.com/senchalabs/connect/graphs/contributors
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
License
MIT