Using the Cache API

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JavaScript

JavaScript

export default {
  async fetch(request, env, ctx) {
    const cacheUrl = new URL(request.url);

    // Construct the cache key from the cache URL
    const cacheKey = new Request(cacheUrl.toString(), request);
    const cache = caches.default;

    // Check whether the value is already available in the cache
    // if not, you will need to fetch it from origin, and store it in the cache
    let response = await cache.match(cacheKey);

    if (!response) {
      console.log(
        `Response for request url: ${request.url} not present in cache. Fetching and caching request.`,
      );
      // If not in cache, get it from origin
      response = await fetch(request);

      // Must use Response constructor to inherit all of response's fields
      response = new Response(response.body, response);

      // Cache API respects Cache-Control headers. Setting s-max-age to 10
      // will limit the response to be in cache for 10 seconds max

      // Any changes made to the response here will be reflected in the cached value
      response.headers.append("Cache-Control", "s-maxage=10");

      ctx.waitUntil(cache.put(cacheKey, response.clone()));
    } else {
      console.log(`Cache hit for: ${request.url}.`);
    }
    return response;
  },
};

TypeScript

TypeScript

interface Env {}
export default {
  async fetch(request, env, ctx): Promise<Response> {
    const cacheUrl = new URL(request.url);

    // Construct the cache key from the cache URL
    const cacheKey = new Request(cacheUrl.toString(), request);
    const cache = caches.default;

    // Check whether the value is already available in the cache
    // if not, you will need to fetch it from origin, and store it in the cache
    let response = await cache.match(cacheKey);

    if (!response) {
      console.log(
        `Response for request url: ${request.url} not present in cache. Fetching and caching request.`,
      );
      // If not in cache, get it from origin
      response = await fetch(request);

      // Must use Response constructor to inherit all of response's fields
      response = new Response(response.body, response);

      // Cache API respects Cache-Control headers. Setting s-max-age to 10
      // will limit the response to be in cache for 10 seconds max

      // Any changes made to the response here will be reflected in the cached value
      response.headers.append("Cache-Control", "s-maxage=10");

      ctx.waitUntil(cache.put(cacheKey, response.clone()));
    } else {
      console.log(`Cache hit for: ${request.url}.`);
    }
    return response;
  },
} satisfies ExportedHandler<Env>;

Python

Python

from workers import WorkerEntrypoint
from pyodide.ffi import create_proxy
from js import Response, Request, URL, caches, fetch

class Default(WorkerEntrypoint):
    async def fetch(self, request):
        cache_url = request.url

        # Construct the cache key from the cache URL
        cache_key = Request.new(cache_url, request)
        cache = caches.default

        # Check whether the value is already available in the cache
        # if not, you will need to fetch it from origin, and store it in the cache
        response = await cache.match(cache_key)

        if response is None:
            print(f"Response for request url: {request.url} not present in cache. Fetching and caching request.")
            # If not in cache, get it from origin
            response = await fetch(request)
            # Must use Response constructor to inherit all of response's fields
            response = Response.new(response.body, response)

            # Cache API respects Cache-Control headers. Setting s-max-age to 10
            # will limit the response to be in cache for 10 seconds s-maxage
            # Any changes made to the response here will be reflected in the cached value
            response.headers.append("Cache-Control", "s-maxage=10")
            self.ctx.waitUntil(create_proxy(cache.put(cache_key, response.clone())))
        else:
            print(f"Cache hit for: {request.url}.")
        return response

Hono

TypeScript

import { Hono } from "hono";
import { cache } from "hono/cache";

const app = new Hono();

// We leverage hono built-in cache helper here
app.get(
  "*",
  cache({
    cacheName: "my-cache",
    cacheControl: "max-age=3600", // 1 hour
  }),
);

// Add a route to handle the request if it's not in cache
app.get("*", (c) => {
  return c.text("Hello from Hono!");
});

export default app;