use Domain in 'carom.js app'

app.js

var app = Object.create(require('carom.js')).constructor()

function onError (err, req, res) {
    console.error(err)
    console.error(err.stack)

    res.writeHead(500)
    res.end(String(err))
}

app.use('favicon')
app.use('doma', onError)
app.use('router', {app: app})
app.use('404')

app.router.GET('/', function (req, res) {
    throw new Error('test throw error !!')
})

app.router.GET('/domain', function (req, res) {
	var domain = this.d

    require('fs').readFile('no_exists.json', 'utf8', domain.intercept(function (data) {
        res.writeHead(200,{'content-type': 'application/json; charset=utf-8'})
        res.end(data)
    }))
})


var port = 3002
app.server.listen(port, function (err) {
    if (err) return console.error(err.stack)
    console.log('server start to listen on port "%d"', port)
})

doma.js

module.exports = function (onError) {
    if ('function' !== typeof onError)
         throw new TypeError('"onError" must be "function"')

    var domain = require('domain')

    return function errorhandling (req, res, next) {
        var context = this
        var d = this.d = domain.create()

        d.on('error', function (err) {
            onError.apply(context, [err, req, res])
        })

        d.run(next)
    }
}