multer - What is the best approach to implement a background job in a MERN app?

Question

I made a small MERN app where users can upload images, and I've used multer for that. While it works fine in development, after deploying to heroku, every time I try to upload an image I get an error with code=H12(Request timeout), and it says that the request took more than 3s to load. After some digging, I found that heroku has a time limit of 3000ms for a request to respond, before giving this error. The only solution is to implement the image uploading as a background job, but I don't even know what to start with as I had never done this before.

What is the best way to implement the image uploading as a background job? Any suggestion or link to tutorial would be very helpful and appreciated.

The route file for image uploading:

const router = require('express').Router();
const multer = require('multer');
const FILE_PATH = 'uploads';

const { uploadPhoto } = require('../controllers/photos/upload-photo');

const storage = multer.diskStorage({
    destination: (req, file, cb) => cb(null, FILE_PATH),
    filename: (req, file, cb) => {
        cb(null, `${Date.now()}_${file.originalname}`)
    },
    fileFilter: (req, file, cb) => {
        if (!file.originalname.match(/.(jpeg|jpg|png|JPG|PNG)$/)) {
            console.log('Only upload jpg and png files.');
        }

        cb(undefined, true);
    },
});

router.post('/upload/:userid', multer({ storage }).single('photo'), uploadPhoto);

module.exports = router;

The controller file for image upload:

const User = require('../../models/User');
const Photo = require('../../models/Photo');

exports.uploadPhoto = (req, res) => {
    //My approach with Multer

    const { file: { mimetype, filename, path }, protocol } = req;
    const url = `${protocol}://${req.get('host')}`;

    User
        .findById(req.params.userid)
        .exec((error, user) => {
            if (error || !user) return res.status(404).json({ message: error.message, });

            const newPhoto = new Photo({
                photo: {
                    mimetype,
                    photoUrl: `${url}/${path}`,
                    name: filename,
                },
                owner: user._id,
            });

            newPhoto.save((error, photo) => {
                if (error) {
                    return res.status(404).json({ message: error.message, });
                }

                user.photos.push(newPhoto._id);
                user.save();

                return res.status(201).json({
                    message: `Image created`,
                    photoUrl: photo.photoUrl,
                });
            });
        });
};

question from:https://stackoverflow.com/questions/65648356/what-is-the-best-approach-to-implement-a-background-job-in-a-mern-app

Answer 1

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