Edge Computing with Cloudflare Workers & Deno · Leçon

Gérer les requêtes HTTP

Écrivez un Worker de base pour intercepter et traiter des requêtes HTTP, afin d’illustrer les fonctionnalités fondamentales.

Gérer les requêtes HTTP est une leçon Edge Computing with Cloudflare Workers & Deno gratuite sur CoddyKit. Ceci est la leçon 2 sur 4. Tu peux lire la leçon complète ci-dessous gratuitement — puis la pratiquer en direct dans le navigateur avec un éditeur de code intégré et un tuteur IA 24/7. Elle fait partie du parcours d'apprentissage Edge Computing with Cloudflare Workers & Deno, et ta progression se synchronise sur le web et l'application CoddyKit. Le cours Edge Computing with Cloudflare Workers & Deno comprend 4 leçons au total.

Certaines parties de cette leçon n'ont pas encore été traduites et s'affichent en anglais.

Workers and Web Requests

Cloudflare Workers are powerful tools that sit at the edge of the internet. Think of them as highly efficient gatekeepers for your web traffic.

Their primary job is to intercept incoming HTTP requests, process them using your code, and then send back an appropriate HTTP response.

Understanding the Request

Every time a user's browser interacts with your Worker, it receives a Request object. This object is packed with all the details about the incoming request:

URL: The full web address the user tried to reach.
Method: The HTTP action, like GET (fetching data) or POST (sending data).
Headers: Extra information such as the browser type, cookies, and preferred language.
Body: Any data sent with the request, common with POST or PUT methods.

Catching the Fetch Event

Cloudflare Workers use an event listener to 'catch' incoming requests. The fetch event is triggered for every HTTP request that hits your Worker.

The standard entry point for a Worker is an exported object with an async fetch method. This method receives the request object as its first argument.

export default {
  async fetch(request, env, ctx) {
    // Your Worker logic goes here
    // The 'request' object holds all incoming request details
    return new Response("Hello from Worker!");
  }
}

Crafting a Simple Response

After your Worker processes a request, it needs to send back a Response object. This object contains the content and metadata that the user's browser will receive.

A basic Response can be created by simply passing a string of text to its constructor.

export default {
  async fetch(request, env, ctx) {
    const responseText = "Welcome to the edge!";
    return new Response(responseText);
  }
}

Your First 'Hello Worker!'

Let's combine what we've learned to create a simple Worker that says "Hello Cloudflare Worker!" to every incoming request.

This is the fundamental structure you'll use for almost all Cloudflare Workers.

export default {
  async fetch(request, env, ctx) {
    return new Response("Hello Cloudflare Worker!");
  }
}

Peeking at the Request URL

You can access various properties of the request object to get information about the incoming request. For example, request.url gives you the full URL that was requested.

This allows you to create dynamic responses based on the specific path or query parameters a user is trying to reach.

export default {
  async fetch(request, env, ctx) {
    const url = request.url;
    return new Response(`You requested: ${url}`);
  }
}

Responding to GET vs. POST

The request.method property tells you the HTTP method used (e.g., GET, POST, PUT, DELETE). You can use this to provide different logic for different types of requests.

For instance, a GET request might fetch data, while a POST request might submit data for creation.

export default {
  async fetch(request, env, ctx) {
    if (request.method === "GET") {
      return new Response("This is a GET request.");
    } else if (request.method === "POST") {
      return new Response("This is a POST request.", { status: 201 });
    }
    return new Response("Method not allowed.", { status: 405 });
  }
}

Custom Headers and Status

You can customize the Response object further by adding HTTP headers or changing the status code. This is done by passing an options object as the second argument to the Response constructor.

Headers: Provide metadata about the response (e.g., Content-Type: text/plain).
Status Code: Indicates the outcome of the request (e.g., 200 OK, 404 Not Found).

export default {
  async fetch(request, env, ctx) {
    return new Response("Custom response!", {
      status: 200,
      headers: {
        "Content-Type": "text/plain",
        "X-Worker-Info": "Processed at the Edge"
      }
    });
  }
}

Fetching from an Origin

Often, your Worker will act as a proxy. This means it fetches content from an 'origin server' (your actual website or API backend) and potentially modifies it before sending it to the user.

You can use the global fetch() function, passing it the original request object, to forward the request to another server.

export default {
  async fetch(request, env, ctx) {
    // Fetch the request from the origin server
    const response = await fetch(request);
    // You can modify the response here before returning it
    return response;
  }
}

Worker Response Check

You're building a Cloudflare Worker. Which of the following correctly sets the status code of a response to 404 Not Found?

Recap: Handling HTTP Requests

In this lesson, you learned the core of Cloudflare Workers: how they handle HTTP requests and send back responses.

Workers intercept fetch events.
The Request object contains all incoming request data.
You return a Response object to the user.
You can access request details like URL and method.
Responses can have custom status codes and headers.
Workers can act as proxies, fetching content from origin servers.

Next, you'll learn the steps to deploy your first Worker to Cloudflare's edge network so it can start serving users globally!

Questions Fréquemment Posées

La leçon « Gérer les requêtes HTTP » est-elle gratuite ?

Oui — le texte complet de « Gérer les requêtes HTTP » est gratuit à lire ici sur le web. Pour la pratiquer de manière interactive (un éditeur de code intégré et un tuteur IA 24/7) et déverrouiller le reste du cours Edge Computing with Cloudflare Workers & Deno, passe à CoddyKit PRO. Le cours Edge Computing with Cloudflare Workers & Deno comprend 4 leçons au total.

Qu'est-ce que j'apprendrai dans « Gérer les requêtes HTTP » ?

Écrivez un Worker de base pour intercepter et traiter des requêtes HTTP, afin d’illustrer les fonctionnalités fondamentales. Tu pratiques Edge Computing with Cloudflare Workers & Deno avec du code pratique que tu exécutes directement dans le navigateur, et un tuteur IA 24/7 répond à tes questions au fur et à mesure que tu avances dans la leçon.

Dois-je avoir de l'expérience pour commencer Edge Computing with Cloudflare Workers & Deno ?

Aucune expérience préalable n'est requise. Edge Computing with Cloudflare Workers & Deno sur CoddyKit est structuré pour les débutants jusqu'aux apprenants avancés, donc tu peux commencer ici ou depuis le début et avancer à ton rythme. Ceci est la leçon 2 sur 4.

Combien de temps prend la leçon « Gérer les requêtes HTTP » ?

La plupart des leçons CoddyKit prennent environ 5–10 minutes. Chacune est courte et interactive, tu progresses régulièrement et tu repiques exactement où tu t'es arrêté sur le web et l'app.

Peux-tu écrire et exécuter du code dans cette leçon Edge Computing with Cloudflare Workers & Deno ?

Oui. Chaque leçon Edge Computing with Cloudflare Workers & Deno inclut un éditeur de code intégré, tu écris et exécutes du vrai code directement dans ton navigateur et tu reçois des retours IA instantanés — aucune configuration locale requise.

Toutes les leçons de ce cours

Configurer l’environnement Worker
Gérer les requêtes HTTP
Déployer votre premier Worker
Variables d’environnement et secrets dans les Workers

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