Same Image not uploading in express - node.js

Question

I am trying to upload an image using express but I am facing two problems, first, whenever I upload the same image again it's not getting uploaded and secondly after uploading any single image a file with image also uploading. Here is my code.
var multer = require('multer');
var uploads = multer({dest: './images'});
app.post('/uploading', uploads.single("file"), function (req, res) {
var file = __dirname +"/images" + "/" + req.file.originalname;
fs.readFile( req.file.path, function (err, data) {
fs.writeFile(file, data, function (err,data) {
if( err ){
console.error( err );
response = {
message: 'Sorry, file couldn\'t be uploaded.',
filename: req.file.originalname
};
}else{
response = {
message: 'File uploaded successfully',
filename: req.file.originalname
};
}
res.end( JSON.stringify( response ) );
});
});
})

Answer 1

The uploads.single("file") middleware Will handle the file upload. You don't have to specifically fs.read and fs.write the file.
var multer = require('multer');
var uploads = multer({dest: './images'});
app.post('/uploading', uploads.single("file"), function (req, res) {
//the file is uploaded automatically
})
EDIT: The above code will upload the file with hex string as filename without any extension.
In order to add rename function you need to use diskStorage. Here is the code taken from this github issue page.
var multer = require('multer');
var storage = multer.diskStorage({
destination: function (req, file, cb) {
cb(null, './images/')
},
filename: function (req, file, cb) {
crypto.pseudoRandomBytes(16, function (err, raw) {
cb(null, raw.toString('hex') + Date.now() + '.' + mime.extension(file.mimetype)); //this is the rename func
});
}
});
var uploads = multer({ storage: storage });
app.post('/uploading', uploads.single("file"), function (req, res) {
//the file is uploaded automatically
})
Now you can use the uploads variable as middleware as shown in the above snippet.
you can edit the filename: function (req, file, cb) { .. } according to your needs. Now the filename will be, <16characterhexstring>.ext

Answer 2

another way to handle it will be not using middleware and using multer manually with below options :
try {
var storage = multer.diskStorage({
destination: function(request, file, callback) {
//define folder here by fs.mkdirSync(anyDirName);
},
filename: function(req, file, callback) {
callback(null, anyFileName);
},
limits: self.limits
});
var upload = multer({
storage: storage,
fileFilter: function(request, file, callback) {
// here you can filter out what not to upload..
}
}).any();
upload(request, response, callback);
} catch (e) {
}
hope this helps!