Node.js File Upload Using Express Multer

Node.js File Upload: This tutorial is based on uploading files to the server in Node.js. You will learn to upload a single file at a time through this tutorial. Even you can validate the uploading file type. Every step is explained with the MVC Pattern. So, It is very easy to understand & use for your project.

There are lots of modules in npm to upload files to the server. But you should use the Multer module for uploading the file. Because It is the most popular & easy to implement in Node.js Express. So, Before using the Multer module, you have to know about the Multer Module with the following points.

• Multer can handle multipart/form-data for uploading files.
• Multer will not work without declaring enctype=”multipart/form-data”  within the form tag.

How to Upload File Using Node.js & Express

You can easily upload the file through the following steps that are very simple to understand.

Learn also – 

How to store Image in MySQL Database using Node.js

How to display Image from MySQL Database in Node.js

1. Install Express Application

First of all, Install Basic Express Application and create more required folders & file

nodeapp/
  |__controllers/
  |     |__file-upload.js
  |__public/
  |     |__files/
  |__middlewares/
  |     |__file-upload.js
  |__routes/
  |     |__file-upload.js
  |__views/
  |     |__file-upload-form.ejs

2. Install Express Multer

First of all, Install multer module using the following command with npm

npm install --save multer

3. Create File Upload Form

File Upload form must have the following attribute

• method=”POST” – To upload the file through the post method
• enctype=”multipart/form-data” –  to handle file uploading
• name=”file – It is the name of the file input Field

File Path: views/file-upload-form.ejs

<form action="/upload" method="POST" enctype="multipart/form-data">
     <label>Avatar</label>
     <input type="file"  name="file">
     <button type="submit">Upload</button>
</form>

4. Upload File to the Folder

You should create a middleware to upload file to the folder using the following points –

• Create a folder middlewares
• Also, create a file file-upload.js in the middlewares
• Declare image folder path in the code cb(null, 'image_folder_path'). Here public/files/ is the path where the file will be uploaded.

File Path: controllers/file-upload.js

var multer = require('multer');

module.exports.files={
    storage:function(){
        var storage = multer.diskStorage({
        destination: function (req, file, cb) {
          cb(null, 'public/files/')
        },
        filename: function (req, file, cb) {
            cb(null, file.originalname)
        }
      })
      
      return storage;
},

allowedFile:function(req, file, cb) {
    
    if (!file.originalname.match(/\.(pdf|doc|txt|jpg|JPG|jpeg|JPEG|png|PNG|gif|GIF)$/)) {
        req.fileValidationError = 'Only  files are allowed!';
        return cb(new Error('Only  files are allowed!'), false);
    }
    cb(null, true);
}


}

5. Send File Upload Request

• Include Multer module require('multer')
• Also, include a middleware file using require('../middlewares/file-upload')
• Create a method fileUploadForm to display file upload form
• Even create another method uploadFile to send file upload requests.

file Path: controllers/upload-controller.js

var multer  = require('multer');
var fileUpload= require('../middlewares/file-upload');


module.exports={
    fileUploadForm:function(req,res){
        res.render('file-upload-form');
     },
     uploadFile:function(req,res){
        var upload = multer({
                    storage: fileUpload.files.storage(), 
                    allowedFile:fileUpload.files.allowedFile 
                    }).single('file');
        upload(req, res, function (err) {
           if (err instanceof multer.MulterError) {
              res.send(err);
           } else if (err) {
              res.send(err);
           }else{
              res.render('file-upload-form');
           }
           
        })
        
     }
}

6. Create a Route File to Upload File

• include a controller file using require('../controllers/file-upload')
• Create a route /upload  with the GET method to display file upload form
• Also, Create another route /upload with the POST method to upload file. This route will be called when you submit the file upload form.

File Pathe: routes/file-upload.js

const express = require('express');
const router = express.Router();
const fileUploadController= require('../controllers/file-upload');

router.get('/upload',fileUploadController.fileUploadForm);

router.post('/upload',fileUploadController.uploadFile);

module.exports = router;

7. Include the Route File in the app.js

At last, You must load the following file uploading route in the main file app.js

var uploadRouter = require('./routes/file-upload');
app.use('/', uploadRouter);

8. Run Node.js App to Upload File

First of all, Start the Node.js server, then enter the following URL in your browser and press Enter.

http://localhost:3000/upload

The above URL displays the file upload form in your browser.

9. My Suggestion

Dear developers, I hope you have understood the above script and you are able to upload files in Node.js express using Multer. Now, you can easily implement another file uploading in Node.js express.

If you have any doubts or questions. You can directly ask me through the below comment box.