Routing e middleware
Utilizzi librerie di routing e pattern middleware per organizzare e potenziare la sua API Worker.
Routing e middleware è una lezione Edge Computing with Cloudflare Workers & Deno gratuita su CoddyKit. Questa è la lezione 2 di 3. Puoi leggere la lezione completa qui gratuitamente — poi esercitati direttamente nel browser con un editor di codice integrato e un tutor IA disponibile 24/7. Fa parte del percorso di apprendimento Edge Computing with Cloudflare Workers & Deno, e i tuoi progressi si sincronizzano tra il web e l'app CoddyKit. Il corso Edge Computing with Cloudflare Workers & Deno include 3 lezioni in totale.
Parti di questa lezione non sono ancora state tradotte e vengono mostrate in inglese.
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.
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Utilizzi librerie di routing e pattern middleware per organizzare e potenziare la sua API Worker. Eserciti Edge Computing with Cloudflare Workers & Deno con codice pratico che esegui direttamente nel browser, e un tutor IA 24/7 risponde alle tue domande mentre lavori sulla lezione.
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Tutte le lezioni di questo corso
- Progettazione di API RESTful
- Routing e middleware
- Validazione e gestione degli errori