Kickstart Your Journey with Fastify for Server-Side Development
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Chapter 1: Introduction to Fastify
Fastify is a lightweight framework designed for building backend applications using Node.js. In this guide, we will explore the steps required to develop backend applications efficiently with Fastify.
Installation
To get started, you need to install the Fastify package. You can do this by using either of the following commands:
npm install fastify --save
or if you prefer Yarn:
yarn add fastify
Creating Your First Application
Let’s create a basic server application with just a few lines of code. The following example demonstrates how to set up a simple server:
const fastify = require('fastify')({
logger: true
})
fastify.get('/', (request, reply) => {
reply.send({ hello: 'world' })
})
fastify.listen(3000, '0.0.0.0', (err, address) => {
if (err) {
fastify.log.error(err)
process.exit(1)
}
fastify.log.info(Server is running at ${address})
})
In this code snippet, we initialize Fastify with logging enabled. The reply.send method is utilized to send a response back to the client. The fastify.listen function initiates the server, with the first parameter specifying the port number and the second indicating the IP address. By setting it to '0.0.0.0', the server listens for requests from all available addresses. When accessing the root route (/), you will receive a JSON response:
{"hello":"world"}
Utilizing Async/Await
Fastify allows the use of async/await in route handlers. Here’s how you can implement it:
const fastify = require('fastify')({
logger: true
})
fastify.get('/', async (request, reply) => {
return { hello: 'world' }
})
const start = async () => {
try {
await fastify.listen(3000, '0.0.0.0')} catch (err) {
fastify.log.error(err)
process.exit(1)
}
}
start()
In this example, we return the desired object directly, and we call fastify.listen without a callback function.
Validating Request Data
To ensure that your application receives valid data, you can validate request payloads by specifying a schema. Here’s an example:
const fastify = require('fastify')({
logger: true
})
const opts = {
schema: {
body: {
type: 'object',
properties: {
foo: { type: 'string' },
bar: { type: 'number' }
}
}
}
}
fastify.post('/', opts, async (request, reply) => {
return { hello: 'world' }
})
const start = async () => {
try {
await fastify.listen(3000, '0.0.0.0')} catch (err) {
fastify.log.error(err)
process.exit(1)
}
}
start()
In this case, we create a schema that defines the expected types for the properties foo and bar, ensuring that only valid data is accepted.
Serializing Response Data
Fastify also allows you to define the response schema. Here’s how you can do that:
const fastify = require('fastify')({
logger: true
})
const opts = {
schema: {
response: {
200: {
type: 'object',
properties: {
hello: { type: 'string' }}
}
}
}
}
fastify.post('/', opts, async (request, reply) => {
return { hello: 'world' }
})
const start = async () => {
try {
await fastify.listen(3000, '0.0.0.0')} catch (err) {
fastify.log.error(err)
process.exit(1)
}
}
start()
This code allows you to specify the expected response structure for the / route.
Running Your Server
You can run your Fastify application using the Fastify CLI. First, install it with the following command:
npm install fastify-cli
Next, add the following script in your package.json:
"scripts": {
"start": "fastify start server.js"
}
Now, you can start your application by running:
npm start
Conclusion
Fastify makes it straightforward to create a basic backend application with Node.js.
For a deeper dive into Fastify, check out the "Fastify Crash Course | Node.js Framework" on YouTube.
Additionally, you can learn about Fastify and its ecosystem in under 15 minutes with the "Learn Fastify and its ecosystem in under 15 Minutes - To build" video.