Sharing Large Files Without Using Cloud Services

26 September 2023

The other day I had to share a large file with my niece but I have run out of space on G Drive and Dropbox and I didn't want to delete any of the files there. So I decided to spin an Express static server and allow her to download the file directly from my computer.

First I had to start the project:

mkdir file-share-server
cd file-share-server
npm init -y
npm install express

After I had the project set up I have copy-pasted the example code for 'hello world' and the static files middleware from the Express documentation in index.js file in the root of the project:

// index.js

const express = require('express')
const app = express()
const port = 3000

app.use(express.static('files'))

app.get('/', (req, res) => {
  res.send('Hello World!')
})

app.listen(port)

Next I have added a start script and in the package.json and also postinstall script creating files folder in the root of the project (files will be served from this folder):

 "scripts": {
    "start": "node index.js",
    "postinstall": "mkdir -p files"
  }

To make the server serve my needs I had to add a few variables. First since this server will be public and without authentication I wanted to generate random string that will be placed in the endpoint and will prevent people from accessing any resources if they don't have the correct url. I also want to have the url generated based on my IP given to me from my ISP. And I will also change the port to something less widely used.

This is the server code after the changes:

// index.js

const express = require('express')
const crypto = require('crypto')

const app = express()
const SECRET = crypto.randomBytes(32).toString('hex')
const PORT = 8008
const IP = 'Change with your ISP IP'

app.use(`/${SECRET}`, express.static('files'))

// Just for testing server is running
app.get('/', function (req, res) {
  res.send('Hello World')
})

app.listen(PORT)

console.log(`
  Link to file you want ot share will be:
  http://${IP}:${PORT}/${SECRET}/full-name-of-file-you-want-to-share-including.extension\n
  Make sure file is in ./files folder
`)

With the server ready I had to find what is my IP and replace the IP variable. Google 'what is my ip' to find what is yours.

Next I had to set port forwarding in my router in order to redirect calls to port 8008 to my machine. To find what is your local IP on Mac or Linux run the following command in the console:

ifconfig | grep "inet " | grep -v 127.0.0.1 | cut -d " " -f 2 | head -n 1

On Widows it should be in Settings > Network & Internet > Ethernet > IPv4 / IPv6 address

With the server running and the router set to redirect requests on port 8008 to your machine you can place files in the files folder and share them with anyone.

I should point out that Google prevents links to be open in Chrome because it is a http server. But downloads were successful with Edge and Firefox.

I recommend shutting down the server and removing/ disabling port forwarding in your router after you are done sharing.

You can get the code for this project from github.

I have also created another version using Bun instead of NodeJS. Find it here: https://github.com/raditotev/file-share-server-with-bun

I