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I just inherited a website where the whole site (including index.html) is cached by a service worker. I deleted the old website and migrated it to WordPress. The problem is that when users visit this website they still see the old site and I don't have a way to clear the cache.
I tried adding headers to Nginx Cache-Control "no-store, must-revalidate"; expires 0; but this had no effect since index.html page was not loaded from the server but directly from service worker cache.
It seems that there is no way for me to update this site at all. Old users are seeing the old version no matter what I do. Is there any way I can disable this service worker or force clear the cache at this point?
You can use some javascript to unregister the service workers
navigator.serviceWorker.getRegistrations().then(function(registrations) {
for(let registration of registrations) {
registration.unregister();
}
});
Source: https://gist.github.com/mrienstra/9c60a76009480e2240770dadb2fb96fe
A more verbose version would be useful for you as well, since it's such a hard problem: https://gist.github.com/mrienstra/9c60a76009480e2240770dadb2fb96fe
@bobbybouwmann but how do I execute that javascript since I cannot change the page?
@martinszeltins The only thing I can think of is doing a DNS redirect to a certain page where you run this script and redirect the user back to another page. It's not the most beautiful solution, but that would be a way to force this.
You can maybe even do this redirect on nginx or apache level. There is no way you're going to make this work in the new code base for sure.
@bobbybouwmann already tried that and it looks like the service worker is caching the domain and does not even make a DNS query. So changing the DNS IP address has no effect.
It looks like there is no way to update this site and I have to tell users to perform a hard refresh or reinstall their browsers. This isn't a problem for new users though since they don't have that cached version.
Honestly, I'm out of ideas here.
@martinszeltins are there any links on the index page that would direct to your server? You could intercept them and send back code to clear the worker?
@Snapey good point, I could use those links but unless a user clicks on one of them the cache will remain. It seems that only the index.html page itself is cached by the service worker but not other resources. I will try to use some existing js file to inject a script to unregister the service worker.
Man, this is a tough situation.
@Snapey oh shoot, it looks like all js files are also cached by the sw :( And waiting for users to click on a link to clear the cache is also not very realistic.
Am I out of options here?
@martinszeltins are there ANY network requests when the user loads the index?
@Snapey yes there is an api request that returns json data.
@martinszeltins I'm out of ideas as well. I guess you can now only contact your users through a different channel and tell them to use that.
@martinszeltins You need to change the contents of the service worker file: https://web.dev/learn/pwa/service-workers/#updating-a-service-worker
One way to do this is to add a “version” to the file, and increment this number when you want the service worker to update.
@martinbean The sw.js file is not versioned and is loaded from the cache (previous developers). So since the service worker is loaded from cache there doesn't seem to be a way to update its content.
@martinszeltins No, you can. If you change the contents of the service worker file as described in the article I linked you to, it will trigger an update.
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