Example for multer upload custom error handling

example-multer-custom-error.js

const express = require('express')
const multer = require('multer');

const app = express();

const storage = multer.diskStorage({
    destination: function (req, file, cb) {
        cb(null, 'tmp')
    },
    filename: function (req, file, cb) {
        cb(null, file.fieldname + '-' + Date.now())
    }
})

const upload = multer({
    storage: storage,
    limits: {
        fileSize: 1024 * 1024 * 5
    },
    fileFilter: (req, file, cb) => {
        if (file.mimetype == "image/png" || file.mimetype == "image/jpg" || file.mimetype == "image/jpeg") {
            cb(null, true);
        } else {
            return cb(new Error('Invalid mime type'));
        }
    }
});

const uploadSingleImage = upload.single('image');

app.post('/upload', function (req, res) {

    uploadSingleImage(req, res, function (err) {

        if (err) {
            return res.status(400).send({ message: err.message })
        }

        // Everything went fine.
        const file = req.file;
        res.status(200).send({
            filename: file.filename,
            mimetype: file.mimetype,
            originalname: file.originalname,
            size: file.size,
            fieldname: file.fieldname
        })
    })
})

app.listen(3000, () => {
    console.log("Server is listening on port: 3000");
});

Hello , why my app is hang when i hit the endpoint twice, if you try on postman, it will hang with "Sending request..." message

This is my code :

R_menu.js

const MW_MULTER = [handlerUploadImage];
router.post("/upload-image", MW_MULTER, C_menu.uploadImage);

MW_menu.js

const handlerUploadImage = (req, res) => {
  console.log("Handler Upload Image middleware reached");

  const h = upload.single("image");
  h(req, res, function (err) {
    if (err) {
      return res.status(400).send({ message: err.message });
    }
  });
};

Hello , why my app is hang when i hit the endpoint twice, if you try on postman, it will hang with "Sending request..." message

This is my code :

R_menu.js

const MW_MULTER = [handlerUploadImage];
router.post("/upload-image", MW_MULTER, C_menu.uploadImage);

MW_menu.js

const handlerUploadImage = (req, res) => {
  console.log("Handler Upload Image middleware reached");

  const h = upload.single("image");
  h(req, res, function (err) {
    if (err) {
      return res.status(400).send({ message: err.message });
    }
  });
};

Every middleware should call next handler or throw error (or smth). Your handlerUploadImage takes 3 parameters: req, res and next. Call next() in your handler, and request will be transferred into C_menu.uploadImage

"Hello @nacza,

I've encountered an issue while uploading '.png' files and it seems you're facing the same problem. Could you please review my code on GitHub (https://github.com/codal-umistri/Multer).

It will help You!