router

Simple middleware-style router

Installation

$ npm install router

API

var finalhandler = require('finalhandler')
var http         = require('http')
var Router       = require('router')

var router = Router()
router.get('/', function (req, res) {
  res.setHeader('Content-Type', 'text/plain; charset=utf-8')
  res.end('Hello World!')
})

var server = http.createServer(function(req, res) {
  router(req, res, finalhandler(req, res))
})

server.listen(3000)

This module is currently an extracted version from the Express project, but with the main change being it can be used with a plain http.createServer object or other web frameworks by removing Express-specific API calls.

Router(options)

Options

• strict - When false trailing slashes are optional (default: false)
• caseSensitive - When true the routing will be case sensitive. (default: false)
• mergeParams - When true any req.params passed to the router will be merged into the router's req.params. (default: false) (example)

Returns a function with the signature router(req, res, callback) where callback([err]) must be provided to handle errors and fall-through from not handling requests.

router.use([path], ...middleware)

Use the given middleware function for all http methods on the given path, defaulting to the root path.

router does not automatically see use as a handler. As such, it will not consider it one for handling OPTIONS requests.

• Note: If a path is specified, that path is stripped from the start of req.url.

router.use(function (req, res, next) {
  // do your things

  // continue to the next middleware
  // the request will stall if this is not called
  next()

  // note: you should NOT call `next` if you have begun writing to the response
})

router[method](path, ...[middleware], handler)

The http methods provide the routing functionality in router.

These are functions which you can directly call on the router to register a new handler for the method at a specified path.

// handle a `GET` request
router.get('/', function (req, res) {
  res.setHeader('Content-Type', 'text/plain; charset=utf-8')
  res.end('Hello World!')
})

Additional middleware may be given before the handler. These middleware behave exactly as normal with one exception: they may invoke next('route'). Calling next('route') bypasses the remaining middleware and handler for this route, passing the request on to the next route.

router.param(name, param_middleware)

Maps the specified path parameter name to a specialized param-capturing middleware.

This function positions the middleware in the same stack as .use.

Parameter mapping is used to provide pre-conditions to routes which use normalized placeholders. For example a :user_id parameter could automatically load a user's information from the database without any additional code:

router.param('user_id', function (req, res, next, id) {
  User.find(id, function (err, user) {
    if (err) {
      return next(err)
    } else if (!user) {
      return next(new Error('failed to load user'))
    }
    req.user = user

    // continue processing the request
    next()
  })
})

router.route(path)

Creates an instance of a single Route for the given path. (See Router.Route below)

Routes can be used to handle http methods with their own, optional middleware.

Using router.route(path) is a recommended approach to avoiding duplicate route naming and thus typo errors.

var api = router.route('/api/')

Router.Route(path)

Represents a single route as an instance that can be used can be used to handle http methods with it's own, optional middleware.

route[method](handler)

These are functions which you can directly call on a route to register a new handler for the method on the route.

// handle a `GET` request
var status = router.route('/status')

status.get(function (req, res) {
  res.setHeader('Content-Type', 'text/plain; charset=utf-8')
  res.end('All Systems Green!')
})

route.all(handler)

Adds a handler for all HTTP methods to this route.

The handler can behave like middleware and call next to continue processing rather than responding.

router.route('/')
.all(function (req, res, next) {
  next()
})
.all(check_something)
.get(function (req, res) {
  res.setHeader('Content-Type', 'text/plain; charset=utf-8')
  res.end('Hello World!')
})

Examples

// import our modules
var http         = require('http')
var Router       = require('router')
var finalhandler = require('finalhandler')
var compression  = require('compression')
var bodyParser   = require('body-parser')

// store our message to display
var message = "Hello World!"

// initialize the router & server and add a final callback.
var router = Router()
var server = http.createServer(function onRequest(req, res) {
  router(req, res, finalhandler(req, res))
})

// use some middleware and compress all outgoing responses
router.use(compression())

// handle `GET` requests to `/message`
router.get('/message', function (req, res) {
  res.statusCode = 200
  res.setHeader('Content-Type', 'text/plain; charset=utf-8')
  res.end(message + '\n')
})

// create and mount a new router for our API
var api = Router()
router.use('/api/', api)

// add a body parsing middleware to our API
api.use(bodyParser.json())

// handle `PATCH` requests to `/api/set-message`
api.patch('/set-message', function (req, res) {
  if (req.body.value) {
    message = req.body.value

    res.statusCode = 200
    res.setHeader('Content-Type', 'text/plain; charset=utf-8')
    res.end(message + '\n')
  } else {
    res.statusCode = 400
    res.setHeader('Content-Type', 'text/plain; charset=utf-8')
    res.end('Invalid API Syntax\n')
  }
})

// make our http server listen to connections
server.listen(8080)

You can get the message by running this command in your terminal, or navigating to 127.0.0.1:8080 in a web browser.

curl http://127.0.0.1:8080

You can set the message by sending it a PATCH request via this command:

curl http://127.0.0.1:8080/api/set-message -X PATCH -H "Content-Type: application/json" -d '{"value":"Cats!"}'

Example using mergeParams

var http         = require('http')
var Router       = require('router')
var finalhandler = require('finalhandler')

// this example is about the mergeParams option
var opts = { mergeParams: true }

// make a router with out special options
var router = Router(opts)
var server = http.createServer(function onRequest(req, res) {

  // set something to be passed into the router
  req.params = { type: 'kitten' }

  router(req, res, finalhandler(req, res))
})

router.get('/', function (req, res) {
  res.statusCode = 200
  res.setHeader('Content-Type', 'text/plain; charset=utf-8')

  // with respond with the the params that were passed in
  res.end(req.params.type + '\n')
})

// make another router with our options
var handler = Router(opts)

// mount our new router to a route that accepts a param
router.use('/:path', handler)

handler.get('/', function (req, res) {
  res.statusCode = 200
  res.setHeader('Content-Type', 'text/plain; charset=utf-8')

  // will respond with the param of the router's parent route
  res.end(path + '\n')
})

// make our http server listen to connections
server.listen(8080)

Now you can get the type, or what path you are requesting:

curl http://127.0.0.1:8080
> kitten
curl http://127.0.0.1:8080/such_path
> such_path

License

MIT