TL;DR

I have created a Magento 2 module - Yireo_DisableServiceWorkerInAdmin - that loads a JavaScript snippet in the Magento Admin Panel, that unregisters any Service Worker currently being active for that specific domain. It's a dirty job and somebody needed to do it.

Caching strategies, offline, push notifications

A PWA is able to introduce new features in the frontend progressively. This might include features like caching, in the end leading to offline strategies, and other features like push notifications. With a lot of these PWA features, it is the Service Worker that allows for the magic to happen.

The Service Worker is basically a piece of JavaScript (sw.js or serviceworker.js), custom built or generated, that is added to the page and activated within the browser. The worker process even keeps on working when the website is not available, with the browser closed or the internet not working (offline).

Not for the backend

While these Service Worker features are cool on the frontend, they are often not needed in the backend. Even worse, sometimes caching features prevent the backend from working properly. In these cases, my new Yireo_DisableServiceWorkerInAdmin extension might come in handy. It simpy unregisters any Service Worker found to be running.

Same domain or different domains?

Because Service Workers are always bound to a specific domain, this is only needed when the Magento Admin Panel and the frontend share the same domain. However, what I personally do a lot is use separate domains instead: For instance, a frontend www.example.org and a backend admin.example.org, so that cookies do not conflict, weird session attacks have less impact. Plus, I can use separate PHP processes for each, so that the frontend has a smaller memory_limit than the backend, for instance.

Anyway, using different domains is not mandatory, you can simply use the same domain for both frontend and backend. And that's where this module might come in handy.

Unregistering?

One down-side is that you can only unregister the Service Worker. With every visit on the frontend, it registers. With every visit on the backend, it registers. It feels kind of awkward, strange. But because only admin users have this impact and because the impact simply leads to some pointless JavaScript execution (while you could say that Magento is excellent in executing pointless JavaScript), this is a non-issue.

Hope you enjoy this little widget.