Download a file from NodeJS server using Express

In this tutorial, we’ll explore how to download a file from a Node.js server using the Express framework.

We’ll cover two scenarios: downloading a single file and downloading multiple files as a zipped folder. Express provides a convenient method, res.download() for handling file downloads.

Downloading a Single File

Let’s create a simple example to download a single file. Assume you have an Express app with a file named app.js.

// Import necessary modules
const express = require('express');
const app = express();

// Set up a route for downloading a single file
app.get('/download', function(req, res){
    const file = `${__dirname}/upload-folder/dramaticpenguin.MOV`;
    res.download(file); // Set disposition and send it.
});

// Start the server
app.listen(3000, function(){
    console.log('Server is listening on port 3000');
});

In this example, when a GET request is made to /download, the server responds by triggering the download of the file dramaticpenguin.MOV. The res.download() method automatically sets the appropriate headers for file download.

The browser interprets the response as a file download and prompts the user to choose a location to save the file.

Downloading Multiple Files as a Zipped Folder

To download multiple files as a zipped folder, we’ll use the express-zip npm package. Install it by running:

npm install express-zip

Now, modify the app.js file:

// Import necessary modules
const express = require('express');
const app = express();
const zip = require('express-zip');

// Set up a route for downloading multiple files as a zip
app.get('/download-multiple', function(req, res){
    // Define an array of file objects with path and name
    const files = [
        { path: 'path/to/file1.txt', name: 'file1.txt' },
        { path: 'path/to/file2.txt', name: 'file2.txt' },
        // Add more files as needed
    ];

    // Use res.zip() to send the files as a zip folder
    res.zip(files);
});

// Start the server
app.listen(3000, function(){
    console.log('Server is listening on port 3000');
});

In this example, when a GET request is made to /download-multiple, the server responds by sending a zip file containing multiple files specified in the files array.

The browser prompts the user to download the zip file and choose a location to save it.

Notes

• Remember that the user has control over the download location through their browser settings. They can choose to save files in their default download directory or select a different destination each time.