fileDriver.js

var ObjectID = require('mongodb').ObjectID,
    fs = require('fs'); // 1

FileDriver = function(db) {
	this.db = db;
};

FileDriver.prototype.getCollection = function(callback) {
	this.db.collection('files', function(error, file_collection) { // 1
		if(error) callback(error);
		else callback(null, file_collection);
	});
};

FileDriver.prototype.get = function(id, callback) {
	this.getCollection(function(error, file_collection) { // 1
		if (error) callback(error);
		else {
			var checkForHexRegExp = new RegExp("^[0-9a-fA-F]{24}$"); // 2
			if (!checkForHexRegExp.test(id)) callback({error: "invalid id"});
			else file_collection.findOne({'_id': ObjectID(id)}, function(error, doc) { //3
				if (error) callback(error);
				else callback(null, doc);
			});
		}
	});
};

FileDriver.prototype.handleGet = function(req, res) { //1
	var fileId = req.params.id;
	if (fileId) {
		this.get(fileId, function(error, thisFile) { // 2
			if (error) { res.send(400, error); }
			else {
				if (thisFile) {
					var filename = fileId + thisFile.ext; // 3
					var filePath = './uploads/' + filename; // 4
					res.sendfile(filePath); // 5
				} else res.send(404, 'file not found');
			}
		});
	} else {
		res.send(404, 'file not found');
	}
};

// To save a new file
FileDriver.prototype.save = function(obj, callback) { //1
	this.getCollection(function(error, the_collection) {
		if (error) callback(error);
		else {
			obj.created_at = new Date();
			the_collection.insert(obj, function() {
				callback(null, obj);
			});
		}
	});
};

FileDriver.prototype.getNewFileId = function(newobj, callback) { // 1
	this.save(newobj, function (err, obj) {
		if (err) { callback(err); }
		else { callback(null, obj._id); } // 3
	});
};

FileDriver.prototype.handleUploadRequest = function(req, res) { // 1
	var ctype = req.get("content-type"); // 2
	var ext = ctype.substr(ctype.indexOf('/')+1); // 3
	if (ext) {ext = '.' + ext; } else {ext = '';}
	this.getNewFileId({'content-type':ctype, 'ext':ext}, function(err, id) { // 4
		if (err) { res.send(400, err); }
		else {
			var filename = id + ext; // 5
			filePath = __dirname + '/uploads/' + filename; // 6

			var writable = fs.createWriteStream(filePath); // 7
			req.pipe(writable); // 8
			req.on('end', function () { //9
				res.send(201, {'_id': id });
			});
			writable.on('error', function(err) { //10
				res.send(500, err);
			});
		}
	});
};

exports.FileDriver = FileDriver;