Express: Send files to the client

Express provides a handy method to transfer a file as attachment:

Once a user hits a route that sends a file using this method, browsers will prompt the user for download.

The method allows you to send a file attached to the request, and the browser instead of showing it in the page, it will save it to disk.

app.get('/', (req, res) =>'./file.pdf'))

In the context of an app:

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

app.get('/', (req, res) =>'./file.pdf'))
app.listen(3000, () => console.log('Server ready'))

You can set the file to be sent with a custom filename:'./file.pdf', 'user-facing-filename.pdf')

This method provides a callback function which you can use to execute code once the file has been sent:'./file.pdf', 'user-facing-filename.pdf', (err) => {
  if (err) {
    //handle error
  } else {
    //do something

Lessons this unit:

0: Introduction
1: Introduction to Express
2: Request parameters
3: Send a response to the client
4: Send a JSON response
5: Manage cookies
6: Work with HTTP headers
7: Handling redirects
8: Routing
9: Template engines
10: Middleware
11: Serving Static Assets with Express
12: ▶︎ Send files to the client
13: Sessions
14: Validating and sanitizing input
15: Handling form data