node.js multer rename uploaded file

Question

I am trying to rename an image file uploaded with multer by the request parameters.

Here is my code:

router.route('/upload/:userid')
.post(multer({
    dest: 'uploads/'
    }), function(req,res){
            fs.readFile('uploads/' + req.files.file.name, function(err, data) {
                fs.writeFile('uploads/' + req.params.userid + '.' + req.files.file.extension, data, function(err) {
                    fs.unlink('uploads/' + req.files.file.name, function(){
                        if(err) throw err;
                    });
                }); 
            });
            res.json({ message: 'Successfully uploaded image!' });
});

It works great but I was wondering if it exists something cleaner and easier with multer rename function.

It already tried something like this:

router.route('/upload/:userid')
.post(multer({
    dest: 'uploads/',
    rename: function(req,res) {
        return req.params.userid
    }
    }), function(req,res){
            res.json({ message: 'Successfully uploaded image!' });
});

But it does not work because req is not populated yet (undefined).

I use httpie to test my code with the following command:

http.exe -f POST http://localhost:8080/upload/171284 file@D:\....\cat.jpg

Is it possible to use rename function of multer to do what I do with fs? Or is there a better way?

Thank you for your feedbacks.

Thomas

EDIT

My new code using diskStorage:

var storage = multer.diskStorage({
    destination: function (req, file, cb) {
    cb(null, 'uploads/')
  },
    filename: function (req, file, cb) {
    cb(null, req.params.userid + '-')
  }
})

var upload = multer({ storage: storage })

router.route('/upload/:userid')
    .post(multer({
        storage: storage
    }), function(req,res){
        res.json({ message: 'Successfully uploaded image!' });
});

That throws an error:

Error: Route.post() requires callback functions but got a [object Object]

Gergo Gergo · Accepted Answer · 2016-02-11T20:49:01

Ther is no rename in Multer constructor, insted of that, there is a filename in DiskStorage.

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

var upload = multer({ storage: storage })

filename is used to determine what the file should be named inside the folder. If no filename is given, each file will be given a random name that doesn't include any file extension.

node.js multer rename uploaded file

1 Answers