How to Create a Zip Backup of Folders in Express.js (with Exclusions)

Keeping regular backups of user-uploaded files or generated content is critical in any web application. If you’re using Express.js and saving files inside the public/storage directory, this guide walks you through creating a .zip backup of the folder — excluding certain subdirectories like backups, assets, or files like .gitignore.

Why Use Zip Archives for Backups?

• Space-efficient thanks to compression
• Easy to download, move, or upload elsewhere
• Simple to automate for regular intervals or on-demand backups

The Backup Logic (Excluding Specific Files/Folders)

Here’s how the create_storage_backup function works:

import fs from 'fs';
import path from 'path';
import archiver from 'archiver';

/**
 * Create backup of storage folder
 * create_storage_backup(['backups', 'assets', '.gitignore']);
 * @param {string[]} exclude
 */
export async function create_storage_backup(exclude = []) {
    const storagePath = path.join('public', 'storage');
    const backupDir = path.join(storagePath, 'backups');

    exclude.push('backups'); // always exclude backup folder itself

    // Format timestamp for the filename: storage-YYYY-MM-DD-HH-mm-ss.zip
    const now = new Date();
    const filename = `storage-${now.getFullYear()}-${(now.getMonth()+1).toString().padStart(2,'0')}-${now.getDate().toString().padStart(2,'0')}-${now.getHours().toString().padStart(2,'0')}-${now.getMinutes().toString().padStart(2,'0')}-${now.getSeconds().toString().padStart(2,'0')}.zip`;

    const zipPath = path.join(backupDir, filename);
    fs.mkdirSync(backupDir, { recursive: true });

    const output = fs.createWriteStream(zipPath);
    const archive = archiver('zip', { zlib: { level: 9 } });

    output.on('close', () => {
        console.log(`Backup created: ${zipPath} (${archive.pointer()} bytes)`);
    });

    archive.on('error', (err) => { throw err; });
    archive.pipe(output);

    // Recursively walk through storage and add files
    const walkDir = (dir, base = '') => {
        fs.readdirSync(dir).forEach((file) => {
            const fullPath = path.join(dir, file);
            const relPath = path.join(base, file);

            const shouldExclude = exclude.some((ex) =>
                relPath === ex || relPath.startsWith(ex + path.sep)
            );

            if (shouldExclude) return;

            const stats = fs.statSync(fullPath);
            if (stats.isDirectory()) {
                walkDir(fullPath, relPath);
            } else if (stats.isFile()) {
                archive.file(fullPath, { name: relPath.replace(/\\/g, '/') });
            }
        });
    };

    walkDir(storagePath);
    await archive.finalize();
}

Protecting the Backup Route (Optional Admin-Only)

Here’s an example route that lets a super admin create a new backup and fetch existing ones:

import { Router } from 'express';
const router = Router();

router.get('/storage-backups', auth, async (req, res) => {
    try {
        if (!is_super_admin(req.user)) {
            return res_json(res, 'Please Login as admin', 403);
        }

        if (String(req.query?.['action'] ?? '') === 'create') {
            await create_storage_backup();
        }

        const backupDir = path.join('public', 'storage', 'backups');
        const items = fs.readdirSync(backupDir).filter(f => f.endsWith('.zip'));
        const latest = items.sort().reverse()[0];

        return res_json(res, {
            items, latest,
            url: url('/storage/backups'),
        });
    } catch (error) {
        return res_json(res, get_error_message(error), 500);
    }
});

Example API Usage

To create a new backup

GET /storage-backups?action=create

To list and fetch backups

GET /storage-backups

Output Example

The backup files will be saved like:

/public/storage/backups/storage-2025-04-25-14-38-20.zip

Access them via your preferred admin panel or direct link.

Final Tips

• This script assumes you’re using Express + ESM modules.
• Use a cron job or scheduled function to call this on intervals.
• Always exclude .gitignore and the backups folder to avoid infinite recursion.
• Store backups off-site (e.g., S3) for extra safety.

Conclusion

This approach gives you a simple, customizable, and secure way to back up your storage files in Express.js. Whether for disaster recovery or audit logs, having compressed archives on hand is a best practice every app should adopt.