Utility to add stale-while-revalidate
and stale-if-error
(see rfc5861) handling to Cloudflare workers via the
Workers Cache API.
The library is very minimalistic and requires almost no code changes, just install the library via:
npm i workers-swr
Then import and wrap your fetch handler with the provided withSWR
function:
import { withSWR } from "workers-swr";
export default {
fetch: withSWR(
// your standard fetch handler goes here
(request, env, ctx) => {
return new Response("Hello World!");
}
),
};
The library will check incoming requests and outgoing responses and implement the swr caching for you.
Warning Note that the workers cache API, which this library uses, is not available in
*.workers.dev
deployments, in order to make use of it you need to deploy your worker to a custom domain.
Note Cloudflare adds a default 4-hour max-age caching to fetch responses, this means that this library by default will make your responses be cached for 4 hours, you can easily change this by changing accordingly the Browser Cache TTL option in the Cloudflare dashboard.
Demo on how this library works (source code): https://workers-swr-demo.dariopiot.net/
- [] Request Cache-Control Directives handling
Note >
no-cache
,no-store
andmax-age
are already handled by the workers cache api- []
max-stale
- []
min-fresh
- []
only-if-cached
- []
-
[] adding a config parameter can be passed to
withSWR
to enable themust-understand
directive -
[] adding the possibility to use a different caching storage (e.g. using KVs instead of the cache api, allowing caching also on
workers.dev
subdomains) (important note: this would also need to make sure we handle all the cache control directives that now the workers api handles for us)