Shut down servers nicely

shutdowner.js

// keeps track of connections to a http server and closes them when the server closes.

function LinkedList() {
    this.start = null
    this.end = null }

LinkedList.prototype.add = function(data) {
    var ref = { data: data, next: null, prev: null }
    if (!this.start) this.start = ref
    if (this.end) {
        this.end.next = ref
        ref.prev = this.end }
    this.end = ref
    return ref }
LinkedList.prototype.remove = function(ref) {
    if (ref == this.start) this.start = ref.next
    if (ref == this.end) this.end = ref.prev
    if (ref.prev) ref.prev.next = ref.next
    if (ref.next) ref.next.prev = ref.prev }

module.exports = function shutdowner(http_server) {
    // TODO: detect when it's already wrapped
    var old_close = http_server.close
    http_server.close = function() {
        this.emit('beforeClose')
        old_close.apply(this, arguments) }

    var conns = new LinkedList()
    var closing = false

    http_server.on('listening', function() {
        http_server.on('connection', function connection_handler(socket) {
            var ref = conns.add(socket)
            socket.on('close', function() {
                conns.remove(ref) })})
        http_server.on('request', function(req, res) {
            // todo: don't mess with the socket
            req.connection._working = true
            res.on('finish', function() {
                req.connection._working = false
                if (closing) req.connection.destroySoon() }) })
        http_server.once('beforeClose', function() {
            closing = true
            for (var conn = conns.start; conn != null; conn = conn.next) {
                if (conn && !conn.data._working) conn.data.destroy() }})})}