Guide to creating a multi-image upload form with Node.js

A step-by-step guide on how to create a multi-image upload form in Node.js using the `Multer` library for file handling and `Express` for server creation.

In this tutorial, we will learn how to use Multer along with Express in Node.js to create a form that allows users to upload multiple images simultaneously.

Node.js code:

1. Install the necessary libraries

npm init -y
npm install express multer

2. Create index.js with the following content:

const express = require('express');
const multer = require('multer');
const path = require('path');
const app = express();

// Multer configuration
const storage = multer.diskStorage({
    destination: function (req, file, cb) {
        cb(null, 'uploads/');
    },
    filename: function (req, file, cb) {
        cb(null, file.fieldname + '-' + Date.now() + path.extname(file.originalname));
    }
});

const upload = multer({ storage: storage });

// Serve static files from the uploads directory
app.use('/uploads', express.static('uploads'));

// Display the upload form
app.get('/', (req, res) => {
    res.send(`
        <form action="/upload" method="POST" enctype="multipart/form-data">
            <input type="file" name="images" multiple>
            <button type="submit">Upload</button>
        </form>
    `);
});

// Route to handle multiple image uploads
app.post('/upload', upload.array('images', 10), (req, res) => {
    res.send('Upload successful! ' + req.files.length + ' images uploaded.');
});

// Start the server
app.listen(3000, () => {
    console.log('Server is running at http://localhost:3000');
});

Detailed explanation:

1. const express = require('express');: Imports the Express library to create a web server.
2. const multer = require('multer');: Imports the Multer library for handling file uploads.
3. multer.diskStorage: Defines where to store uploaded files and their names.
4. app.use('/uploads', express.static('uploads')): Sets up a static route to access uploaded files.
5. upload.array('images', 10): Allows uploading up to 10 images at once.
6. app.get('/'): Route to display the upload form.
7. app.post('/upload'): Route to handle the image upload process.

System Requirements:

• Node.js version 14 or higher
• Libraries express and multer

How to install the libraries needed to run the Node.js code above:

Use the following command:

npm install express multer

Tips:

• Always validate the file size and type before uploading for security.
• Limit the number and size of images to prevent server overload.

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