Outlook: Add column in the Network activity log to track why resources are not loaded from DiskCache when ServiceWorker is present

[dicaryl]

We don't have a lot of intuitive insight into ServiceWorkers and whether Network activity is ultimately serviced from Disk or Network.

It would be great if we could instrument the cache-fail points in network requests (e.g., you can imagine that the browser internally checks Cache header, ETag header, Expires header, etc. etc.. We can't get into Service Worker logic of course (since that's script-managed) but we could create a new panel (even a column) that indicates that we were appropriately serviced by the cache.

It would also be excellent to know why it's not coming from DiskCache when a ServiceWorker is present!

[captainbrosset]

Interesting. Let me double-check my understanding.

On a typical webpage (not using a service worker), the Network tool does provide the information you're looking for in the Size column, as seen below:

However on a PWA, with a service worker, the Network tool only says if a request was handled by the worker, as seen here in the Size column:

So what you're saying is that it'd be really good if the tool would provide more information than this for service worker-handled requests, right? Maybe something like replacing the (ServiceWorker) string with (ServiceWorker - DiskCache) and (ServiceWorker - Network)?

How about this: if you go to about:serviceworker-internals, find your service worker in the list, and then click Inspect, you'll get a DevTools instance just for the worker. In this instance, you can also use the Network tool and there, you should only see the requests that are made to the network. Everything else that hits the cache will not be displayed.

Does that help?

[dicaryl]

This is not currently a PWA, so we're talking about the first experience rather than the second one. The main question is in the failure case - where have a service worker, and we expect it to service from the DiskCache, but we still see network activity. We'd like better visibility into why we're hitting the network. Was something out of date, or did we install the service worker correctly, etc.?

[vidorteg]

Hi everyone,

We have been working in revamping some features that you might want to try (some are available today on Microsoft Edge Canary Channel):

• [On Canary] We added a new column named: 'Fulfilled by' which contains information on who was the original initiator of the request.
• [On Canary] We added the ability to persist this new column in the HAR file.
• [Coming soon to canary] We are adding the ability to persist pending requests (useful for debugging)

I'll still capture the feedback provided in this post, but please let us know if any of the new features were address or were useful in the issue you mentioned.

[captainbrosset]

@dicaryl did you get a chance to take a look at the new Fulfilled by column in the Network tool? Does this help?