TingoDB

It is possible to build application that will transparently support both MongoDB and TingoDB. Here are some hints that help to do it:

• Wrap module require call into helper module or make it part of core object. This way you can control which engine is loaded in single place.
• Use only native JavaScript types. BSON types can be slow in JavaScript and will need special attention when passed to or from client JavaScript.
• Think about ObjectID as of just unique value that can be converted to and from String regardless its actual meaning.

Most of these approaches already implemented in Mongoose.js ODM library and there is expirimental driver that trasparently links it with TingoDB.

For more simple dual usage example please take a look to this code that consists from 3 files.

engine.js – wrapper on TingoDB and MongoDB

var fs = require('fs'),db,engine;

// load config
var cfg = JSON.parse(fs.readFileSync("./config.json"));

// load requestd engine and define engine agnostic getDB function
if (cfg.app.engine=="mongodb") {
    engine = require("mongodb");
    module.exports.getDB = function () {
        if (!db) db = new engine.Db(cfg.mongo.db,
            new engine.Server(cfg.mongo.host, cfg.mongo.port, cfg.mongo.opts),
                {native_parser: false, safe:true});
        return db;
    }
} else {
    engine = require("tingodb")({});
    module.exports.getDB = function () {
        if (!db) db = new engine.Db(cfg.tingo.path, {});
        return db;
    }
}
// Depending on engine this can be different class
module.exports.ObjectID = engine.ObjectID;

sample.js – Dummy usage example, pay attention to comments

var engine = require('./engine');
var db = engine.getDB();

console.time("sample")
db.open(function(err,db) {
    db.collection("homes", function (err, homes) {
        // its fine to create ObjectID in advance
        // NOTE!!! we get class thru engine because its type
        // can depends on database type
        var homeId = new engine.ObjectID();
        // but with TingoDB.ObjectID righ here it will be negative
        // which means temporary. However its uniq and can be used for 
        // comparisons
        console.log(homeId);
        homes.insert({_id:homeId, name:"test"}, function (err, home) {
            var home = home[0];
            // in this place homeID will change its value and will be in sync
            // with database
            console.log(homeId,home);
            db.collection("rooms", function (err, rooms) {
                for (var i=0; i<5; i++) {
                    // its ok also to not provide id, then it will be
                    // generated
                    rooms.insert({name:"room_"+i,_idHome:homeId}, function (err, room) {
                        console.log(room[0]);
                        i--;
                        if (i==0) {
                            // now lets assume we serving request like
                            // /rooms?homeid=_some_string_
                            var query = "/rooms?homeid="+homeId.toString();
                            // dirty code to get simulated GET variable
                            var getId = query.match("homeid=(.*)")[1];
                            console.log(query, getId)
                            // typical code to get id from external world
                            // and use it for queries
                            rooms.find({_idHome:new engine.ObjectID(getId)})
                                .count(function (err, count) {
                                    console.log(count);
                                    console.timeEnd("sample");
                            })
                        }
                    })
                }
            })
        })
    })
})

config.json – Dummy config

{
    "app":{
        "engine":"tingodb"
    },
    "mongo":{
        "host":"127.0.0.1",
        "port":27017,
        "db":"data",
        "opts":{
            "auto_reconnect": true,
            "safe": true
        }
    },
    "tingo":{
        "path":"./data"
    }
}

Console output running on TingoDB

-2
13 { _id: 13, name: 'test' }
{ name: 'room_0', _idHome: 13, _id: 57 }
{ name: 'room_1', _idHome: 13, _id: 58 }
{ name: 'room_2', _idHome: 13, _id: 59 }
{ name: 'room_3', _idHome: 13, _id: 60 }
{ name: 'room_4', _idHome: 13, _id: 61 }
/rooms?homeid=13 13
5
sample: 27ms

Console output running on MongoDB

51b43a05f092a1c544000001
51b43a05f092a1c544000001 { _id: 51b43a05f092a1c544000001, name: 'test' }
{ name: 'room_3',
  _idHome: 51b43a05f092a1c544000001,
  _id: 51b43a05f092a1c544000005 }
{ name: 'room_2',
  _idHome: 51b43a05f092a1c544000001,
  _id: 51b43a05f092a1c544000004 }
{ name: 'room_1',
  _idHome: 51b43a05f092a1c544000001,
  _id: 51b43a05f092a1c544000003 }
{ name: 'room_0',
  _idHome: 51b43a05f092a1c544000001,
  _id: 51b43a05f092a1c544000002 }
{ name: 'room_4',
  _idHome: 51b43a05f092a1c544000001,
  _id: 51b43a05f092a1c544000006 }
/rooms?homeid=51b43a05f092a1c544000001 51b43a05f092a1c544000001
5
sample: 22ms