added udp capacity to the servers file

lib/servers.js

@@ -1,10 +1,10 @@
 'use strict';
 
 var serversMap = module.exports._serversMap = {};
-
-module.exports.addTcpListener = function (port, handler) {
+var dgramMap = module.exports._dgramMap = {};
 var PromiseA = require('bluebird');
 
+module.exports.addTcpListener = function (port, handler) {
   return new PromiseA(function (resolve, reject) {
     var stat = serversMap[port];
 
@@ -34,7 +34,7 @@ module.exports.addTcpListener = function (port, handler) {
     stat = serversMap[port] = {
       server: server
     , handler: handler
-    , _closing: false
+    , _closing: null
     };
 
     // Add .destroy so we can close all open connections. Better if added before listen
@@ -69,8 +69,6 @@ module.exports.addTcpListener = function (port, handler) {
   });
 };
 module.exports.closeTcpListener = function (port) {
-  var PromiseA = require('bluebird');
-
   return new PromiseA(function (resolve) {
     var stat = serversMap[port];
     if (!stat) {
@@ -101,10 +99,79 @@ module.exports.destroyTcpListener = function (port) {
   stat = null;
 };
 
+module.exports.addUdpListener = function (port, handler) {
+  return new PromiseA(function (resolve, reject) {
+    var stat = dgramMap[port];
+
+    if (stat) {
+      // we'll replace the current listener
+      stat.handler = handler;
+      resolve();
+      return;
+    }
+
+    var dgram = require('dgram');
+    var server = dgram.createSocket('udp4');
+    var resolved = false;
+
+    stat = dgramMap[port] = {
+      server: server
+    , handler: handler
+    };
+
+    server.on('message', function (msg, rinfo) {
+      msg._size = rinfo.size;
+      msg._remoteFamily = rinfo.family;
+      msg._remoteAddress = rinfo.address;
+      msg._remotePort = rinfo.port;
+      msg._port = port;
+      stat.handler(msg);
+    });
+
+    server.on('error', function (err) {
+      if (!resolved) {
+        delete dgramMap[port];
+        reject(err);
+      }
+      else if (stat.handler.onError) {
+        stat.handler.onError(err);
+      }
+      else {
+        throw err;
+      }
+    });
+
+    server.on('close', function () {
+      delete dgramMap[port];
+    });
+
+    server.bind(port, function () {
+      resolved = true;
+      resolve();
+    });
+  });
+};
+module.exports.closeUdpListener = function (port) {
+  var stat = dgramMap[port];
+  if (!stat) {
+    return PromiseA.resolve();
+  }
+
+  return new PromiseA(function (resolve) {
+    stat.server.once('close', resolve);
+    stat.server.close();
+  });
+};
+
+
 module.exports.listeners = {
   tcp: {
     add: module.exports.addTcpListener
   , close: module.exports.closeTcpListener
   , destroy: module.exports.destroyTcpListener
   }
+, udp: {
+    add: module.exports.addUdpListener
+  , close: module.exports.closeUdpListener
+  }
 };