Fastify #

Fastify is a web framework for Node.js designed to be highly efficient and performant. It focuses on speed and low overhead while providing a rich set of features for building web applications and APIs. Here’s a basic overview of the Fastify framework in Node.js:

Installation: #

Install Fastify using npm:

npm install fastify

Hello World Example: #

Create a simple Fastify app with a “Hello, World!” route:

const fastify = require('fastify')();

fastify.get('/', async (request, reply) => {
    return 'Hello, World!';
});

fastify.listen(3000, (err) => {
    if (err) throw err;
    console.log('Server is running on port 3000');
});

Access the application by navigating to http://localhost:3000 in your web browser.

Routing: #

Define routes using various HTTP methods:

fastify.get('/about', async (request, reply) => {
    return 'About Us';
});

fastify.post('/api/data', async (request, reply) => {
    // Handle POST request
});

Middleware: #

Use middleware functions for tasks such as logging, authentication, and request/response manipulation:

fastify.use((request, reply, done) => {
    console.log('Middleware executed');
    done();
});

Schema Validation: #

Fastify supports JSON schema-based validation for both incoming requests and outgoing responses:

fastify.post('/validate', {
    schema: {
        body: {
            type: 'object',
            properties: {
                name: { type: 'string' },
                age: { type: 'integer' }
            },
            required: ['name']
        }
    }
}, async (request, reply) => {
    // Validated request body
    return `Hello, ${request.body.name}!`;
});

Plugin System: #

Extend Fastify functionality through plugins. Plugins encapsulate features, routes, and middleware:

const myPlugin = (fastify, options, next) => {
    fastify.decorate('myFunction', () => 'This is my function');
    next();
};

fastify.register(myPlugin);

fastify.get('/plugin', async (request, reply) => {
    return fastify.myFunction();
});

Dependency Injection: #

Leverage Fastify’s built-in dependency injection for organizing and injecting dependencies into routes and plugins:

const myDependency = () => 'Dependency Value';

fastify.decorate('myDependency', myDependency);

fastify.get('/inject', async (request, reply) => {
    return fastify.myDependency();
});

Error Handling: #

Implement error handling using reply to send error responses:

fastify.get('/error', async (request, reply) => {
    reply.code(500).send({ error: 'Internal Server Error' });
});

Logging: #

Customize logging with Fastify’s built-in logger or integrate external logging libraries:

fastify.log.info('This is an info message');
fastify.log.error('This is an error message');

Asynchronous Hooks: #

Utilize hooks for performing actions at various stages of the request/response lifecycle:

fastify.addHook('onRequest', async (request, reply) => {
    console.log('On Request Hook');
});

Fastify is known for its speed and efficiency, making it a suitable choice for performance-critical applications. It provides a clean and organized way to build web applications and APIs, focusing on simplicity, extensibility, and adherence to best practices in modern web development. The framework’s emphasis on simplicity and performance makes it a popular choice for developers seeking a lightweight yet feature-rich solution for their Node.js applications.