ExpressJS Multer: Upload image to server - express

Question

I'm newer with Node.js and Express.js.
I want to upload first a image into the server (directory: uploads/spots), and then (synchronous) upload the rest of form data in MongoDB.
I'm using REST (Method Post)
app.route('/spots').post(users.requiresLogin, spots.create);
and I'm using Multer for updating the image into the server, and works.
app.use(multer(
{ dest: './public/uploads/spots',
onFileUploadStart: function (file) {
var imagePath = file.path;
gm(imagePath).resize(850, 850).quality(70).noProfile().write('public/uploads/spots/850x850/'+file.name, function (err) {
if (!err) {
gm(imagePath).resize(150, 150).quality(70).noProfile().write('public/uploads/spots/150x150/'+file.name, function (err) {
if (!err) {
}
else{
console.log('Error: '+err);
}
});
}
else{
console.log('Error: '+err);
}
});
}
}));
Is working, but is asynchronous , and returns the response to frontend before that the image will be upload into the server.
My question is how to do this but synchronous and how to return the response to the frontend after that the image was uploaded.
Thank you!
spots.server.routes.js
'use strict';
module.exports = function(app) {
var gm = require('gm');
var multer = require('multer');
var users = require('../controllers/users.server.controller.js');
var spots = require('../controllers/spots.server.controller.js');
//Upload image
app.use(multer(
{ dest: './public/uploads/spots',
onFileUploadStart: function (file) {
var imagePath = file.path;
gm(imagePath).resize(850, 850).quality(70).noProfile().write('public/uploads/spots/850x850/'+file.name, function (err) {
if (!err) {
gm(imagePath).resize(150, 150).quality(70).noProfile().write('public/uploads/spots/150x150/'+file.name, function (err) {
if (!err) {
}
else{
console.log('Error: '+err);
}
});
}
else{
console.log('Error: '+err);
}
});
}
}));
// Spots Routes
app.route('/spots')
.get(spots.list)
.post(users.requiresLogin, spots.create);
app.route('/spots/:spotId')
.get(spots.read)
.put(users.requiresLogin, spots.update)
.delete(users.requiresLogin, spots.hasAuthorization, spots.delete);
// Finish by binding the Spot middleware
app.param('spotId', spots.spotByID);
};
spots.server.controller.js (create method)
'use strict';
/**
* Module dependencies.
*/
var mongoose = require('mongoose'),
errorHandler = require('./errors.server.controller.js'),
Spot = mongoose.model('Spot'),
_ = require('lodash'),
fs = require('fs');
/**
* Create a Spot
*/
exports.create = function(req, res) {
var spot = new Spot(JSON.parse(req.body.spot));
spot.user = req.user;
if(req.files.file)
spot.image=req.files.file.name;
else
spot.image='default.jpg';
spot.save(function(err) {
if (err) {
fs.unlinkSync('public/uploads/spots/'+spot.image);
fs.unlinkSync('public/uploads/spots/850x850/'+spot.image);
fs.unlinkSync('public/uploads/spots/150x150/'+spot.image);
return res.status(400).send({
message: errorHandler.getErrorMessage(err)
});
} else {
var socketio = req.app.get('socketio'); // tacke out socket instance from the app container
socketio.sockets.emit('spot.created.'+spot.municipality, {spot:spot, user:req.user});
socketio.sockets.emit('spot.created.'+spot.province, {spot:spot, user:req.user});
socketio.sockets.emit('spot.created.'+spot.community, {spot:spot, user:req.user});
socketio.sockets.emit('spot.created.'+spot.country, {spot:spot, user:req.user});
res.jsonp(spot);
}
});
};
/**
* Spot authorization middleware
*/
exports.hasAuthorization = function(req, res, next) {
if (req.spot.user.id !== req.user.id) {
return res.status(403).send('User is not authorized');
}
next();
};

Answer 1

The solution is not use onFileUploadStart method and use a function with callback in the controller.
routes
// Spots Routes
app.route('/spots')
.get(spots.list)
.post(users.requiresLogin,multer({ dest: './public/uploads/spots'}), spots.create);
controller
exports.create = function(req, res) {
if (req.files.file)
exports.uploadImage(req.files.file,callback);
else
callback();
function callback(){
var spot = new Spot(JSON.parse(req.body.spot));
spot.user = req.user;
if (req.files.file)
spot.image = req.files.file.name;
else
spot.image = 'default.jpg';
spot.save(function (err) {
if (err) {
fs.unlink('public/uploads/spots/850x850/'+spot.image);
fs.unlink('public/uploads/spots/150x150/'+spot.image);
return res.status(400).send({
message: errorHandler.getErrorMessage(err)
});
} else {
var socketio = req.app.get('socketio'); // tacke out socket instance from the app container
socketio.sockets.emit('spot.created.' + spot.municipality, {spot: spot, user: req.user});
socketio.sockets.emit('spot.created.' + spot.province, {spot: spot, user: req.user});
socketio.sockets.emit('spot.created.' + spot.community, {spot: spot, user: req.user});
socketio.sockets.emit('spot.created.' + spot.country, {spot: spot, user: req.user});
req.spot = spot;
Feedback.subscribeSpot(req);
Notify.getLocalSubscriptors(spot.municipality,spot.province,spot.community,spot.country,function(subscriptions){
Notify.create(req,null,spot,null,null,null,subscriptions,'spots/'+spot._id,false,'SPOT_CREATED', function(){
res.jsonp(spot);
});
});
}
});
}
};
exports.uploadImage = function(file, fn){
var imagePath = file.path;
gm(imagePath).resize(850, 850).quality(70).noProfile().write('public/uploads/spots/850x850/'+file.name, function (err) {
if (!err) {
gm(imagePath).resize(150, 150).quality(70).noProfile().write('public/uploads/spots/150x150/'+file.name, function (err) {
if (!err) {
if(fn)fn();
}
else{
console.log('Error: '+err);
}
});
}
else{
console.log('Error: '+err);
}
});
};