Managing uploads and downloads

We need to add two more functionalities to our application, and we will do it by developing a dedicated Fastify plugin. The first will allow our users to upload CSV files to create to-do tasks in bulk. We will rely on two external dependencies to do it:

• @fastify/multipart for file uploads
• csv-parse for CSV parsing

The second plugin will expose an endpoint to download items as a CSV file. Again, we need the external csv-stringify library to serialize objects and create the document.

While we will split the code into two snippets in the book, the complete code can be found in ./routes/todos/files/routes.js. Let’s explore the following snippet, which contains the file upload and items bulk creation logic:

const fastifyMultipart = require('@fastify/multipart')
const { parse: csvParse } = require('csv-parse')
// ... omitted for brevity
  await fastify.register(fastifyMultipart, { // [1]
 &...