Node.js File upload Single File Upload using multer
Example
Remember to
- create folder for upload (
uploadsin example). - install multer
npm i -S multer
server.js:
var express = require("express");
var multer = require('multer');
var app = express();
var fs = require('fs');
app.get('/',function(req,res){
res.sendFile(__dirname + "/index.html");
});
var storage = multer.diskStorage({
destination: function (req, file, callback) {
fs.mkdir('./uploads', function(err) {
if(err) {
console.log(err.stack)
} else {
callback(null, './uploads');
}
})
},
filename: function (req, file, callback) {
callback(null, file.fieldname + '-' + Date.now());
}
});
app.post('/api/file',function(req,res){
var upload = multer({ storage : storage}).single('userFile');
upload(req,res,function(err) {
if(err) {
return res.end("Error uploading file.");
}
res.end("File is uploaded");
});
});
app.listen(3000,function(){
console.log("Working on port 3000");
});
index.html:
<form id = "uploadForm"
enctype = "multipart/form-data"
action = "/api/file"
method = "post"
>
<input type="file" name="userFile" />
<input type="submit" value="Upload File" name="submit">
</form>
Note:
To upload file with extension you can use Node.js path built-in library
For that just require path to server.js file:
var path = require('path');
and change:
callback(null, file.fieldname + '-' + Date.now());
adding a file extension in the following way:
callback(null, file.fieldname + '-' + Date.now() + path.extname(file.originalname));
How to filter upload by extension:
In this example, view how to upload files to allow only certain extensions.
For example only images extensions. Just add to var upload = multer({ storage : storage}).single('userFile'); fileFilter condition
var upload = multer({
storage: storage,
fileFilter: function (req, file, callback) {
var ext = path.extname(file.originalname);
if(ext !== '.png' && ext !== '.jpg' && ext !== '.gif' && ext !== '.jpeg') {
return callback(new Error('Only images are allowed'))
}
callback(null, true)
}
}).single('userFile');
Now you can upload only image files with png, jpg, gif or jpeg extensions
