Function handleRequest

workers/analytics/src/index.js:20–50

(event)

})

async function handleRequest(event) {
    const request = event.request

    // Only GET requests work with this proxy.
    if (request.method !== 'GET') return MethodNotAllowed(request)

    // https://developers.cloudflare.com/workers/examples/cache-api
    const cacheURL = new URL(request.url);

    const cacheKey = new Request(cacheURL.toString(), request);
    const cache = caches.default

    let response = await cache.match(cacheKey);

    if (!response) {
        // If not in cache, get it from origin
        response = await fetch(GTM_URL);

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

        response.headers.append("Cache-Control", `s-maxage=${CACHE_EXPIRY}`)

        // Store the fetched response as cacheKey
        // Use waitUntil so you can return the response without blocking on
        // writing to cache
        event.waitUntil(cache.put(cacheKey, response.clone()))
    }

    return response
}

// Use the following when the request is not a valid GET request
function MethodNotAllowed(request) {