Vue.js 3 Express: Single & Multiple Files and Images Upload

Let’s get started.

Set Up Project

Use command to install Vue project:

vue create vue-single-multi-files-upload

Enter inside the project:

cd vue-single-multi-files-upload

Start the app in the browser:

npm run serve

Configure Bootstrap

Open the public/index.html file and add the Bootstrap CDN link.

<link rel="stylesheet" href="https://stackpath.bootstrapcdn.com/bootstrap/4.4.1/css/bootstrap.min.css" integrity="sha384-Vkoo8x4CGsO3+Hhxv8T/Q5PaXtkKtu6ug5TOeNV6gBiFeWPGFN9MuhOf23Q9Ifjh">

Install Axios Library

Install Axios library in Vue.js app to make the API requests.

# NPM
npm install axios --save


# Yarn
yarn add axios

Build Express/Node Server

We will be uploading files and images in the remote server so that we will create a backend server using Node. Create file upload API using Express.js and store it in the MongoDB database.

Create a server folder at the root of your Vue.js project.

mkdir server && cd server

Create package.json for node server.

npm init

We need to install the following dependencies.

npm i --save cors express mongoose multer body-parser

We have to install the nodemon package to re-start the node server.

Define MongoDB Database

Create server/db/database.js file and folder, here we will define the mongoDB database.

module.exports = {
  db: 'mongodb://localhost:27017/fileupload'
}

Create Schema

Create server/models folder, create a new file and name it User.js.

const mongoose = require('mongoose');
const Schema = mongoose.Schema;

let userSchema = new Schema({
  _id: mongoose.Schema.Types.ObjectId,
  files: {
    type: Array
  },
}, {
  collection: 'users'
})

module.exports = mongoose.model('User', userSchema)

Create File Upload API

Create a new folder server/public, and we are going to store uploaded files in this folder.

mkdir public

Next, we need to create a server/routes folder; in this folder, we have to create user.routes.js file. Add all the following code inside the routes file.

let express = require('express'),
  multer = require('multer'),
  mongoose = require('mongoose'),
  router = express.Router();

const DIR = './public/';

const storage = multer.diskStorage({
  destination: (req, file, cb) => {
    cb(null, DIR);
  },
  filename: (req, file, cb) => {
    const fileName = file.originalname.toLowerCase().split(' ').join('-');
    cb(null, fileName)
  }
});

var upload = multer({
  storage: storage,
  fileFilter: (req, file, cb) => {
    if (file.mimetype == "image/png" || file.mimetype == "image/jpg" || file.mimetype == "image/jpeg") {
      cb(null, true);
    } else {
      cb(null, false);
      return cb(new Error('Only .png, .jpg and .jpeg format allowed!'));
    }
  }
});

// User model
let User = require('../models/User');

router.post('/file-upload', upload.array('files', 10), (req, res, next) => {
  const reqFiles = []
  const url = req.protocol + '://' + req.get('host')
  for (var i = 0; i < req.files.length; i++) {
    reqFiles.push(url + '/public/' + req.files[i].filename)
  }

  const user = new User({
    _id: new mongoose.Types.ObjectId(),
    files: reqFiles
  });
  user.save().then(result => {
    console.log(result);
    res.status(201).json({
      message: "Done upload!",
      userCreated: {
        _id: result._id,
        files: result.files
      }
    })
  }).catch(err => {
    console.log(err),
      res.status(500).json({
        error: err
      });
  })
})

router.get("/", (req, res, next) => {
  User.find().then(data => {
    res.status(200).json({
      message: "Data fetched!",
      users: data
    });
  });
});

module.exports = router;

The Multer package provides the upload.array method. This method takes two parameters, the file name and the total number of files to be uploaded to the server.

You can have a look at the full Multer documentation here.

Set up Node Server

Next, we need to create a server/index.js file. In this file, we define all the server related settings.

let express = require('express'),
  mongoose = require('mongoose'),
  cors = require('cors'),
  bodyParser = require('body-parser'),
  dbConfig = require('./db/database');


// Routes to Handle Request
const userRoute = require('../server/routes/user.routes')


// MongoDB Setup
mongoose.Promise = global.Promise;
mongoose.connect(dbConfig.db, {
  useNewUrlParser: true,
  useUnifiedTopology: true
}).then(() => {
  console.log('Database sucessfully connected')
},
  error => {
    console.log('Database could not be connected: ' + error)
  }
)

// Setup Express.js
const app = express();
app.use(bodyParser.json());
app.use(bodyParser.urlencoded({
  extended: false
}));
app.use(cors());


// Make Images "Uploads" Folder Publicly Available
app.use('/public', express.static('public'));


// API Route
app.use('/api', userRoute)

const port = process.env.PORT || 4000;
const server = app.listen(port, () => {
  console.log('Connected to port ' + port)
})


// Error
app.use((req, res, next) => {
  // Error goes via `next()` method
  setImmediate(() => {
    next(new Error('Something went wrong'));
  });
});

app.use(function (err, req, res, next) {
  console.error(err.message);
  if (!err.statusCode) err.statusCode = 500;
  res.status(err.statusCode).send(err.message);
});

Run the Express Server

Open the terminal window and run the following command to start the MongoDB database.

mongod --config /usr/local/etc/mongod.conf

brew services start mongodb-community@4.2

mongo

Start the nodemon server:

nodemon index.js

Here are the file upload API we created:

We have created the File Uploading API using Node and Express.js. Now let us test out our newly built API using Postmen.

Create Single & Multiple Files Uploading Component

In this step we will build Single & Multiple Files and Images Uploading component.

First, create a component/fileUpload.vue in Vue app. Then, add the following code inside of it.

<template>
  <div>
    <div class="container">
        <form @submit.prevent="handleSubmit">
            <div class="form-group">
                <input type="file" @change="uploadFile" multiple>
            </div>

            <div class="form-group">
                <button class="btn btn-success btn-block btn-lg">Upload</button>
            </div>
        </form>
    </div>    
  </div>
</template>

<script>
import axios from "axios";

export default {
  data() {
      return {
        files: null
      };
    },
    methods: {
        uploadFile (event) {
        this.files = event.target.files
        },
        handleSubmit() {
          const formData = new FormData();
          for (const i of Object.keys(this.files)) {
            formData.append('files', this.files[i])
          }
          axios.post('http://localhost:4000/api/file-upload', formData, {
          }).then((res) => {
            console.log(res)
          })
        }  
    }

}
</script>

<style scoped lang="scss">
.container {
  max-width: 600px;
}
</style>

The axios.post() method takes the file uploading API that we created using Express.js; the second parameter is the form data that we are sending to the server in multi-parts.

The Object.keys() method returns an array of a given object’s enumerable property names, here we are extracting the files from the FileList API by iterating in the same order that a standard loop does.

Summary

So this was it, in this tutorial, we have learned how to upload files to the express server using Axios and FormData() web API. I hope you loved this articles. Don’t forget to share it with others.

You can download the complete code of this tutorial here.