Server-Side Development with Fastify — Sending Responses

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Fastify is a small Node framework for developing back end web apps.

In this article, we’ll look at how to create back end apps with Fastify.

Strings Responses

We can send a string response with the reply.send method:

const fastify = require('fastify')({})
fastify.get('/', function(req, reply) {
  reply.send('plain string')
})
const start = async () => {
  try {
    await fastify.listen(3000, '0.0.0.0')
  } catch (err) {
    fastify.log.error(err)
    process.exit(1)
  }
}
start()

Stream Response

We can send a stream response with reply.send .

For instance, we can write:

index.js

const fastify = require('fastify')({})
fastify.get('/', function(req, reply) {
  const fs = require('fs')
  const stream = fs.createReadStream('some-file', 'utf8')
  reply.send(stream)
})
const start = async () => {
  try {
    await fastify.listen(3000, '0.0.0.0')
  } catch (err) {
    fastify.log.error(err)
    process.exit(1)
  }
}
start()

some-file

foo