An example NodeJS / Mongoose / Express application based on their respective tutorials

api.js

/* The API controller
   Exports 3 methods:
   * post - Creates a new thread
   * list - Returns a list of threads
   * show - Displays a thread and its posts
*/


var Thread = require('../models/thread.js');
var Post = require('../models/post.js');

exports.post = function(req, res) {
    new Thread({title: req.body.title, author: req.body.author}).save();
}

exports.list = function(req, res) {
  Thread.find(function(err, threads) {
    res.send(threads);
  });
}

// first locates a thread by title, then locates the replies by thread ID.
exports.show = (function(req, res) {
    Thread.findOne({title: req.params.title}, function(error, thread) {
        var posts = Post.find({thread: thread._id}, function(error, posts) {
          res.send([{thread: thread, posts: posts}]);
        });
    })
});

app.js

// The main application script, ties everything together.

var express = require('express');
var mongoose = require('mongoose');
var app = module.exports = express.createServer();

// connect to Mongo when the app initializes
mongoose.connect('mongodb://localhost/norum');

app.configure(function(){
  app.use(express.bodyParser());
  app.use(express.methodOverride());
  app.use(app.router);
});

// set up the RESTful API, handler methods are defined in api.js
var api = require('./controllers/api.js');
app.post('/thread', api.post);
app.get('/thread/:title.:format?', api.show);
app.get('/thread', api.list);

app.listen(3000);
console.log("Express server listening on port %d", app.address().port);

post.js

// The Post model

var mongoose = require('mongoose')
   ,Schema = mongoose.Schema
   ,ObjectId = Schema.ObjectId;

var postSchema = new Schema({
    thread: ObjectId,
    date: {type: Date, default: Date.now},
    author: {type: String, default: 'Anon'},
    post: String
});

module.exports = mongoose.model('Post', postSchema);

thread.js

// The Thread model

var mongoose = require('mongoose')
  , Schema = mongoose.Schema;

var threadSchema = new Schema({
    title:  String,
    postdate: {type: Date, default: Date.now},
    author: {type: String, default: 'Anon'}
});

module.exports = mongoose.model('Thread', threadSchema);

Thank you! you are the best!