fastify

Web Server

Fastify allows you to create a web server that can handle HTTP requests and send responses. The above code demonstrates setting up a simple server that responds with JSON when the root route is accessed.

const fastify = require('fastify')({ logger: true });

fastify.get('/', async (request, reply) => {
  return { hello: 'world' };
});

fastify.listen(3000, (err, address) => {
  if (err) throw err;
  fastify.log.info(`server listening on ${address}`);
});

Route Shorthand Methods

Fastify provides shorthand methods for different HTTP methods like GET, POST, etc. This makes it easy to define routes for various request types.

fastify.get('/example', (request, reply) => {
  reply.send({ message: 'This is a GET request' });
});

fastify.post('/example', (request, reply) => {
  reply.send({ message: 'This is a POST request' });
});

Schema Validation

Fastify supports schema validation for request payloads, query strings, and parameters using JSON Schema. This ensures that the data received is in the expected format.

const schema = {
  body: {
    type: 'object',
    required: ['name'],
    properties: {
      name: { type: 'string' },
      age: { type: 'number' }
    }
  }
};

fastify.post('/user', { schema }, (request, reply) => {
  // Handle request knowing that the body has been validated against the schema
});

Plugins

Fastify has a powerful plugin system that allows you to extend its core functionality. Plugins can add new features, routes, services, and decorators to the Fastify instance.

const myPlugin = async (fastify, options) => {
  fastify.decorate('utility', () => {
    return 'something useful';
  });
};

fastify.register(myPlugin);

// Now you can use fastify.utility() in your application

Lifecycle Hooks

Fastify provides lifecycle hooks that can be used to execute code at various stages of the request/response cycle, such as onRequest, preHandler, onResponse, etc.

fastify.addHook('onRequest', (request, reply, done) => {
  // Perform some operations before the request handler is executed
  done();
});