Roteamento e middleware
Utilize bibliotecas de roteamento e padrões de middleware para organizar e aprimorar sua API de Worker.
Roteamento e middleware é uma aula grátis de Edge Computing with Cloudflare Workers & Deno no CoddyKit. Esta é a aula 2 de 3. Você pode ler a aula completa abaixo gratuitamente — depois pratica ao vivo no navegador com um editor de código integrado e um tutor de IA 24/7. Faz parte do caminho de aprendizado de Edge Computing with Cloudflare Workers & Deno, e seu progresso é sincronizado entre a web e o app CoddyKit. O curso de Edge Computing with Cloudflare Workers & Deno inclui 3 aulas no total.
Partes desta aula ainda não foram traduzidas e aparecem em inglês.
API Routing Essentials
When building APIs, we need a way to direct incoming requests to the correct functions based on their URL path and HTTP method (GET, POST, etc.). This process is called routing.
Think of it like a receptionist for your API. When a request comes in, the router checks its destination and sends it to the right department (your code handler).
Manual Worker Routing
In a Cloudflare Worker, all incoming requests are handled by the fetch event listener. You can manually inspect the request's URL and method to decide what to do.
While possible for simple cases, this approach quickly becomes complex and hard to manage as your API grows.
export default {
async fetch(request) {
const url = new URL(request.url);
if (url.pathname === '/hello' && request.method === 'GET') {
return new Response('Hello from manual route!');
}
return new Response('Not Found', { status: 404 });
}
}Introducing itty-router
To simplify routing, we use lightweight libraries. For Cloudflare Workers, itty-router is a popular choice. It's tiny, fast, and designed for the edge.
It provides a clean, expressive way to define routes and handlers, making your Worker code much more organized.
Basic GET Routes
With itty-router, you can define routes using methods like router.get() for GET requests. Each route takes a path and a handler function.
Let's create a simple Worker that responds to / and /greet.
import { Router } from 'itty-router';
const router = Router();
router.get('/', () => new Response('Welcome to the API!'));
router.get('/greet', () => new Response('Hello there!'));
export default {
fetch: router.handle
};Handling All HTTP Methods
itty-router allows you to define routes for specific HTTP methods like .post(), .put(), .delete(), and more.
You can also use .all() to match any HTTP method for a given path, useful for middleware or generic handlers.
import { Router } from 'itty-router';
const router = Router();
router.get('/data', () => new Response('GET data'));
router.post('/data', () => new Response('POST data', { status: 201 }));
router.all('*', () => new Response('Method Not Allowed', { status: 405 }));
export default {
fetch: router.handle
};Dynamic Route Parameters
Often, you need to extract dynamic values from the URL, like an item ID or a username. These are called route parameters.
itty-router uses a colon (:) to define parameters in a route path. The values are then available in the handler's request.params object.
import { Router } from 'itty-router';
const router = Router();
router.get('/users/:id', ({ params }) => {
return new Response(`Fetching user ${params.id}`);
});
export default {
fetch: router.handle
};What is Middleware?
Middleware functions are code snippets that run before or after your main route handler. They can modify the request, perform logging, check authentication, or add headers to the response.
They act as a pipeline, allowing you to add common functionalities across multiple routes without duplicating code.
Implementing Simple Middleware
With itty-router, middleware can be added to specific routes or globally. A middleware function receives the request and can return a response (ending the chain) or continue to the next handler.
Let's add a simple logging middleware that runs for every request.
import { Router } from 'itty-router';
const router = Router();
const loggerMiddleware = async (request, event) => {
console.log(`Request: ${request.method} ${request.url}`);
// To proceed to the next handler, don't return a Response.
// If you return a Response, the chain stops.
};
router.all('*', loggerMiddleware);
router.get('/hello', () => new Response('Hello from route!'));
export default {
fetch: router.handle
};Chaining Middleware
You can chain multiple middleware functions. Each middleware executes in order. If a middleware doesn't return a response, the next one in the chain (or the final route handler) is called.
This allows for powerful, modular processing of requests, like authentication, data parsing, and logging.
import { Router } from 'itty-router';
const router = Router();
const authMiddleware = async (request) => {
if (request.headers.get('Authorization') !== 'Bearer token123') {
return new Response('Unauthorized', { status: 401 });
}
};
const headerMiddleware = async (request, event) => {
// Add a custom header to the response later
event.response = new Response('', { headers: { 'X-Powered-By': 'CoddyKit' } });
};
router.get('/secure', authMiddleware, (request) => {
return new Response('Access granted!');
});
router.get('/info', headerMiddleware, (request) => {
return new Response('Info page');
});
export default {
fetch: async (request, env, ctx) => {
const response = await router.handle(request, env, ctx);
// Merge headers from middleware if present
if (ctx.response && response) {
for (let [key, value] of ctx.response.headers.entries()) {
response.headers.set(key, value);
}
}
return response;
}
};Routing & Middleware Check
Consider a Cloudflare Worker using itty-router. You want to ensure that all requests to /admin/* paths require an X-Admin-Key header, and if it's missing, return a 403 Forbidden response. Other paths should not be affected.
Recap: Routing & Middleware
You've mastered the fundamentals of organizing your edge API with routing and middleware!
- Routing directs requests to the right handlers.
- Libraries like
itty-routersimplify route definition, including dynamic parameters. - Middleware functions enhance requests/responses, adding common logic like logging or authentication before (or after) the main handler.
These patterns are crucial for building scalable and maintainable serverless APIs at the edge.
Perguntas Frequentes
A aula “Roteamento e middleware” é grátis?
Sim — o texto completo de “Roteamento e middleware” é grátis para ler aqui na web. Para praticá-la interativamente (um editor de código integrado e um tutor de IA 24/7) e desbloquear o restante do curso de Edge Computing with Cloudflare Workers & Deno, atualize para CoddyKit PRO. O curso de Edge Computing with Cloudflare Workers & Deno inclui 3 aulas no total.
O que vou aprender em “Roteamento e middleware”?
Utilize bibliotecas de roteamento e padrões de middleware para organizar e aprimorar sua API de Worker. Você pratica Edge Computing with Cloudflare Workers & Deno com código prático que executa diretamente no navegador, e um tutor de IA 24/7 responde suas dúvidas enquanto trabalha na aula.
Preciso ter experiência prévia para começar Edge Computing with Cloudflare Workers & Deno?
Nenhuma experiência prévia é necessária. Edge Computing with Cloudflare Workers & Deno no CoddyKit é estruturado para alunos iniciantes até avançados, então você pode começar aqui ou desde o início e aprender no seu ritmo. Esta é a aula 2 de 3.
Quanto tempo leva a aula “Roteamento e middleware”?
A maioria das aulas CoddyKit leva cerca de 5–10 minutos. Cada uma é compacta e interativa, então você faz progresso constante e retoma exatamente de onde parou entre web e app.
Posso escrever e executar código nesta aula de Edge Computing with Cloudflare Workers & Deno?
Sim. Cada aula de Edge Computing with Cloudflare Workers & Deno inclui um editor de código integrado, então você escreve e executa código real direto no navegador e recebe feedback de IA instantaneamente — nenhuma configuração local necessária.
Todas as aulas deste curso
- Projetando APIs RESTful
- Roteamento e middleware
- Validação e tratamento de erros