Cache POST requests
Cache POST requests using the Cache API.
export default { async fetch(request, env, ctx) {
async function sha256(message) { // encode as UTF-8 const msgBuffer = await new TextEncoder().encode(message); // hash the message const hashBuffer = await crypto.subtle.digest('SHA-256', msgBuffer); // convert bytes to hex string return [...new Uint8Array(hashBuffer)] .map((b) => b.toString(16).padStart(2, '0')) .join(''); } try { if (request.method.toUpperCase() === 'POST') {
const body = await request.clone().text(); // Hash the request body to use it as a part of the cache key const hash = await sha256(body); const cacheUrl = new URL(request.url); // Store the URL in cache by prepending the body's hash cacheUrl.pathname = '/posts' + cacheUrl.pathname + hash; // Convert to a GET to be able to cache const cacheKey = new Request(cacheUrl.toString(), { headers: request.headers, method: 'GET', }); const cache = caches.default; // Find the cache key in the cache let response = await cache.match(cacheKey); // Otherwise, fetch response to POST request from origin if (!response) { response = await fetch(request); ctx.waitUntil(cache.put(cacheKey, response.clone())); } return response; } return fetch(request); } catch (e) { return new Response('Error thrown ' + e.message); } },
};
async function sha256(message) { // encode as UTF-8 const msgBuffer = new TextEncoder().encode(message);
// hash the message const hashBuffer = await crypto.subtle.digest('SHA-256', msgBuffer);
// convert bytes to hex string return [...new Uint8Array(hashBuffer)].map(b => b.toString(16).padStart(2, '0')).join('');
}
async function handlePostRequest(event) { const request = event.request; const body = await request.clone().text();
// Hash the request body to use it as a part of the cache key const hash = await sha256(body); const cacheUrl = new URL(request.url);
// Store the URL in cache by prepending the body's hash cacheUrl.pathname = '/posts' + cacheUrl.pathname + hash;
// Convert to a GET to be able to cache const cacheKey = new Request(cacheUrl.toString(), { headers: request.headers, method: 'GET', });
const cache = caches.default;
// Find the cache key in the cache let response = await cache.match(cacheKey);
// Otherwise, fetch response to POST request from origin if (!response) { response = await fetch(request); event.waitUntil(cache.put(cacheKey, response.clone())); } return response;
}
addEventListener('fetch', event => { try { const request = event.request; if (request.method.toUpperCase() === 'POST') return event.respondWith(handlePostRequest(event)); return event.respondWith(fetch(request)); } catch (e) { return event.respondWith(new Response('Error thrown ' + e.message)); }
});