Analytics using MongoDB aggregation and Node.js

app.js

// The code is based on a MongoDB database myhome with a typical record as below:
// {
//	"rec_time" : ISODate("2013-11-25T16:53:43.808Z"),
//	"rec_data" : {
//		"power" : 372.201,
//		"current" : 1.73,
//		"voltage" : 221.678,
//	},
//	"rec_asset" : {
//		"name" : "Airconditioner",
//		"room" : "Bed_1",
//	},
// }

var MongoClient = require('mongodb').MongoClient;

var express = require('express');
var app = express.createServer();
app.use(express.bodyParser());

MongoClient.connect("mongodb://mongodbhost:port/myhome", function(err, db) {
	app.get('/setup', function(req, res) {
		db.createCollection('test', function(err, collection) {
			db.collection('records').find({}, {rec_time:1}, {sort:{rec_time:1}, limit:1}, function(err, cursor)	{
				cursor.toArray(function(err, docs) {
					if(!err){
						var startDate = docs[0].rec_time;
						startDate.setUTCHours(0,0,0,0);
						startDate.setDate(1);
						db.collection('records').find({}, {rec_time:1}, {sort:{rec_time:-1}, limit:1}, function(err, cursor)	{
							cursor.toArray(function(err, docs) {
								if(!err){
									var endDate = docs[0].rec_time;
									endDate.setUTCHours(0,0,0,0);
									endDate.setDate(1);
									endDate.setMonth(endDate.getMonth() + 1);
									db.collection('readings').aggregate([
										{$match:	{
											"rec_time":{$gt:startDate, $lt:endDate},
										}}, 
										{$project: {
											"rec_time":1,
											"rec_Year" : { $year : "$rec_time"}, 
											"rec_Month": { $month : "$rec_time" },
											"rec_Day": { $dayOfMonth : "$rec_time" },
											"rec_Hour": { $hour : "$rec_time" },
											"rec_data":1,
											"rec_asset":1,
										}}, 
										{$group: {
											_id: {rec_asset_name:"$rec_asset.name", rec_asset_room:"$rec_asset.room",
												rec_Year: "$rec_Year", rec_Month:"$rec_Month", rec_Day:"$rec_Day", rec_Hour:"$rec_Hour"},
											count: { $sum: 1 }, 
											avgVolt : {$avg:"$rec_data.voltage"},
											avgCurrent:{$avg:"$rec_data.current"},
											sumPower:{$sum:"$rec_data.power"},
											avgPower:{$avg:"$rec_data.power"},
										}}
									], function(err, result)	{
											db.collection("agg").insert(result, function(err, docs)	{
												if(err) console.log('Error inserting data');
												else	{
													db.collection("agg").insert({"lastrun":endDate}, function(err, docs)	{
														if(err) console.log('Error inserting lastrun');
														else {
															console.log('Completed aggregation');
															res.end('Initial aggregation completed successfully');
														}
													});
												}
											});
									});
								}
							});
						});
					}
				});
			});
		});
	});

	app.post('/room/year', function(req, res) {
		db.collection('agg').aggregate([
			{$match: {"_id.rec_asset_room": req.body.room, "_id.rec_Year": parseInt(req.body.year)
			}},
			{$group: {
				_id: null,
				avgVolt : {$avg:"$avgVolt"},
				avgCurrent:{$avg:"$avgCurrent"},
				sumPower:{$sum:"$sumPower"},
				avgPower:{$avg:"$avgPower"},
			}}
		], function(err, result)	{
				if(err)	{
					console.log(err);
				}
				else	{
					res.json(result);
				}
			}
		);
	});

	app.post('/room/month', function(req, res) {
		db.collection('agg').aggregate([
			{$match: {"_id.rec_asset_room": req.body.room, "_id.rec_Year": parseInt(req.body.year), "_id.rec_Month": parseInt(req.body.month)
			}},
			{$group: {
				_id: null,
				avgVolt : {$avg:"$avgVolt"},
				avgCurrent:{$avg:"$avgCurrent"},
				sumPower:{$sum:"$sumPower"},
				avgPower:{$avg:"$avgPower"},
			}}
		], function(err, result)	{
				if(err)	{
					console.log(err);
				}
				else	{
					res.json(result);
				}
			}
		);
	});

	app.post('/room/day', function(req, res) {
		db.collection('agg').aggregate([
			{$match: {"_id.rec_asset_room": req.body.room, "_id.rec_Year": parseInt(req.body.year), "_id.rec_Month": parseInt(req.body.month),
					"_id.rec_Day": parseInt(req.body.day)
			}},
			{$group: {
				_id: null,
				avgVolt : {$avg:"$avgVolt"},
				avgCurrent:{$avg:"$avgCurrent"},
				sumPower:{$sum:"$sumPower"},
				avgPower:{$avg:"$avgPower"},
			}}
		], function(err, result)	{
				if(err)	{
					console.log(err);
				}
				else	{
					res.json(result);
				}
			}
		);
	});

	app.listen(3000);
});