A bit more convenient way of routing when developing on expressjs. And add a context object to request

dispatcher.js

/**
 * Path array: [method, pattern, function]
 * 
 * Usage in app.js:
 * var dispatcher = require('./routes').getDispatcher(app);
 * 
 * dispatcher.routes('root',
 *   ['get', '/', 'index']
 * );
 * 
 * dispatcher.routes('auth',
 *   ['gp', '/auth/login', 'login'],
 *   ['post', '/auth/logout', 'logout'],
 *   ['gp', '/auth/signup', 'signup']
 * );
 * 
 * TODO: make the third element of path optional.
 */ 
function Dispatcher(app) {
  // Create a shortcut for GET and POST.
  app.gp = function() {
    app.get.apply(app, arguments);
    app.post.apply(app, arguments);
  }
  this.app = app;
}

module.exports.getDispatcher = function(app) {
  return new Dispatcher(app);
}

/**
 * routes(module_name, path1, path2, ...)
 */
Dispatcher.prototype.routes = function() {
  var name = arguments[0];
  var submodule = require('./' + name);
  for (var i = 1; i < arguments.length; i ++) {
    var entry = arguments[i];
    if (entry.length < 3) {
      continue;
    }
    var fn = this.app[entry[0]];
    fn.call(this.app, entry[1], this.beforeEntry, submodule[entry[2]]);
  }
}

/**
 * Before every entry, add a context object to request.
 * Common context variables can be added here.
 * 
 * So in routes:
 * exports.index = function(req, res) {
 *   ctx = req.context.extend({'title', 'Express'});
 *   res.render('index', ctx);
 */
Dispatcher.prototype.beforeEntry = function(req, res, next) {
  req.context = new RequestContext();
  next();
}

RequestContext = function() {}

RequestContext.prototype.extend = function(items) {
  for (var itemname in items) {
    this[itemname] = items[itemname];
  }
  return this;
}