an implementation of the gridfs-stream module by the awesome @mleanos

node_multer_gridfs.js

'use strict';

var mongoose = require('mongoose'),
	path = require('path'),
	errorHandler = require(path.resolve('./modules/core/server/controllers/errors.server.controller')),
	_ = require('lodash');

var Grid = require('gridfs-stream');
Grid.mongo = mongoose.mongo;
var gfs = new Grid(mongoose.connection.db);

/*
 * Use MongoDb's built in GridFS feature for file system object storage.
 * // testing this 
 * We will merely use GridFS to upload a file, and to retrieve it. Every other interactions should be 
 * at the application level (domain-specific).
 * 
 */
exports.create = function(req, res) {
	console.log('inside upload.create()');
	var part = req.files.file;

	console.log(part);
	var writeStream = gfs.createWriteStream({
		filename: part.originalname,
		mode: 'w',
		content_type: part.mimetype
	});

	writeStream.on('close', function(file) {

		// remove md5 hash from file data, for security reasons
		delete file.md5;
		console.log(file);
		return res.status(200).send({
			message: 'Success',
			// return necessary file data with the response
			data: file
		});
	});

	writeStream.write(part.buffer);
	writeStream.end();
};

exports.read = function(req, res) {
	console.log('inside uploads.read()');
	console.log(req.params.uploadId.toString());
	gfs.files.find({
		_id: mongoose.Types.ObjectId.createFromHexString(req.params.uploadId)
	}).toArray(function(err, files) {

		if (files.length === 0) {
			return res.status(400).send({
				message: 'File not found'
			});
		}

		res.writeHead(200, {
			'Content-Type': files[0].contentType
		});
		var readstream = gfs.createReadStream({
			filename: files[0].filename
		});

		readstream.on('data', function(data) {
			res.write(data);
		});

		readstream.on('end', function() {
			res.end();
		});

		readstream.on('error', function(err) {
			console.log('An error occurred!', err);
			throw err;
		});
	});
};

exports.remove = function(req, res) {
	gfs.remove({
		_id: mongoose.Types.ObjectId.createFromHexString(req.params.uploadId.toString())
	}, function(err) {
		if (err) {
			console.log('Error removing file');
			console.log(err);
			return res.status(400).send({
				message: errorHandler.getErrorMessage(err)
			});
		}
		return res.status(200).send({
			message: 'file remove ' + req.params.id
		});
	});
};