Multer - Stop File Uploading If Form Validation Fails - node.js

Question

i have mixed form with file upload and normal form fields, and while sending this form to Nodejs server i am validating form but problem is that i do not know how to stop uploading the file if (for example) one of the form field is empty.
so for example:
if(name.trim().length < 1){
//stop uploading of file
return res.status(409).send({
message: 'provide name'
})
}
how can i do that (Multer & ExpressJS)?

Answer 1

I was using following code in my case (node & express).
From routes.js file I am calling this insertRating method. like below
//routes.js
router.post('/common/insertrating',RatingService.insertRating);
//controller class
// storage & upload are configurations
var storage = multer.diskStorage({
destination: function (req, file, cb) {
var dateObj = new Date();
var month = dateObj.getUTCMonth() + 1; //months from 1-12
var year = dateObj.getUTCFullYear();
console.log("month and yeare are " + month + " year " + year);
var quarterMonth = "";
var quarterYear = "";
var dir_path = '../../uploads/' + year + '/' + quarterMonth;
mkdirp(dir_path, function (err) {
if (err) {
console.log("error is cominggg insidee");
}
else {
console.log("folder is createtd ")
}
cb(null, '../../uploads/' + year + '/' + quarterMonth)
})
console.log("incomingggg to destination");
},
filename: function (req, file, cb) {
console.log("incoming to filename")
cb(null, Date.now() + "_" + file.originalname);
},
});
var upload = multer({
storage: storage,
limits: {
fileSize: 1048576 * 5
},
fileFilter: function (req, file, callback) {
var ext = path.extname(file.originalname);
ext = ext.toLowerCase();
console.log("ext isss " + ext);
if (ext !== '.png' && ext !== '.jpg' && ext !== '.jpeg' && ext !== '.pdf' && ext !== '.txt'
&& ext !== '.doc' && ext !== '.docx' && ext !== '.xlsx' && ext !== '.xls'
) {
return callback(new Error('Only specific extensions are allowed'))
}
callback(null, true)
}
}).array('files', 5);
// calling below insertRating method from routes js file...
exports.insertRating = async function (req, res) {
let quarterData = req.query.quarterData;
quarterData = JSON.parse(quarterData);
if (quarterData != null) { // here you can check your custom condition like name.trim().length
req.files = []; // not required
upload(req, res, async function (err) { // calling upload
if (err) {
res.send("error is cominggg")
return;
} else {
res.send("file is uploaded");
}
//
});
}
else {
res.send("filed must not be empty");
}
}

Answer 2

You can simply throw error:
in express::
app.get("/upload-image", multterUpload.single("image"), (req, res, next)=>{
try{
if(name.trim().length < 1) {
throw new Error("name length is not valid");
//or
return res.status(409).json({msg: "failed"});
}
// you all operation ....
res.status(200).json({msg: "success"});
}cathc(e=>{
next(e)
});
})
this is something you can do or you can return something else instead of throwing an error.