Using a URL query parameter to version cached responses - caching

Question

I am trying to cache specific urls and each url has md5 hash and If the urls updated with new md5 i want to remove the current cache and add the new one.
cached url: http://www.mysite.lo/cards/index.php?md5=f51c2ef7795480ef2e0b1bd24c9e07
function shouldFetch(event) {
if ( event.request.url.indexOf( '/cards/') == -1 ) {
return false;
}
return true;
}
self.addEventListener('fetch', function(event) {
if (shouldFetch(event)) {
event.respondWith(
caches.match(event.request).then(function(response) {
if (response !== undefined) {
return response;
} else {
return fetch(event.request).then(function (response) {
let responseClone = response.clone();
caches.open('v1').then(function (cache) {
cache.put(event.request, responseClone);
});
return response;
}).catch(function (err) {
return caches.match(event.request);
});
}
})
);
}
});
I know we can use caches.delete() and so on, but I want to call it only if the md5 updated from the new request.
Thanks

Answer 1

You can accomplish roughly what you describe with the following, which makes use of the ignoreSearch option when calling cache.matchAll():
self.addEventListener('fetch', (event) => {
const CACHE_NAME = '...';
const url = new URL(event.request.url);
if (url.searchParams.has('md5')) {
event.respondWith((async () => {
const cache = await caches.open(CACHE_NAME);
const cachedResponses = await cache.matchAll(url.href, {
// https://developers.google.com/web/updates/2016/09/cache-query-options
ignoreSearch: true,
});
for (const cachedResponse of cachedResponses) {
// If we already have the incoming URL cached, return it.
if (cachedResponse.url === url.href) {
return cachedResponse;
}
// Otherwise, delete the out of date response.
await cache.delete(cachedResponse.url);
}
// If we've gotten this far, then there wasn't a cache match,
// and our old entries have been cleaned up.
const response = await fetch(event.request);
await cache.put(event.request, response.clone());
return response;
})());
}
// Logic for non-md5 use cases goes here.
});
(You could make things slightly more efficient by rearranging some of the cache-manipulation code to bring it out of the critical response path, but that's the basic idea.)