index.js

'use strict';

var assert = require('assert'),
  director = require('director'),
  EventEmitter = require('events').EventEmitter,
  ns,// = require('continuation-local-storage').createNamespace('testing'),
  express = require('express'),
  app = express(),
  domain = require('domain');

var domainStorage = (function () {
  var id = 0;
  var storage = {};

  return {
    run: function (func) {
      var currDomain = domain.create();
      currDomain.run(function () {
        var currId = id;
        process.domain.id = currId;
        storage[currId] = {};
        id++;
        func();
      });
    },
    set: function (key, value) {
      storage[process.domain.id][key] = value;
    },
    get: function (key) {
      return storage[process.domain.id][key];
    }
  };
}());

ns = domainStorage;

/*
 * CONSTANTS
 */
var NUM_TESTS = 1000;

function createRouter() {
  var emitter = new EventEmitter(),
    router = new director.http.Router();

  var createHandler = function() {
    return function() {
      assert(ns.get('req'), "req propagated to Router handler");
      emitter.emit('routeMatched', ns.get('req').someId);
    };
  };

  var ret = {
    _createHandler: createHandler,
    initialize: function() {
      router.on('get', '/page/:id', ret._createHandler( /* route, routeFunction */ ));
    },
    on: emitter.on.bind(emitter),
    once: emitter.once.bind(emitter),
    dispatch: function(req, res) {
      assert(ns.get('req'), "req propagated to Router dispatch");
      router.dispatch(req, res, function(err) {
        console.log(err);
      });
    }
  };

  return ret;
}

var router = createRouter();
router.initialize();


// use a real req object from express
app.use(function(req, res, next) {
  ns.run(function() {
    req.someId = Math.floor(Math.random() * Date.now());
    ns.set('someId', req.someId);
    next();
  });
});

app.use(function(req, res, next) {
  ns.set('req', req);
  ns.set('res', res);
  router.dispatch(req, res, function() {
    next();
  });
})

app.listen(4567);

// fake request test

function spawnAsync(i) {
  var req = {
    url: '/page/' + i,
    method: 'get',
    someId: Math.floor(Math.random() * Date.now()),
    headers: {
      'content-type': 'text/html'
    }
  };

  ns.set('req', req);

  process.nextTick(router.dispatch.bind(router, req));
}

router.on('routeMatched', function(id) {
  assert(id, "id passed to routeMatched listener");
  assert(ns.get('req'), "req propagated to routeMatched listener");
  assert.equal(id, ns.get('req').someId, "passed id and req.someId match");
  console.log('ok');
});

// actually do the thing
for (var i = 0; i < NUM_TESTS; i++) ns.run(spawnAsync.bind(null, i));

package.json

{
  "name": "clsbughunt",
  "dependencies": {
    "continuation-local-storage": "~2.1.1",
    "director": "~1.2.0",
    "express": "~3.4.0"
  }
}