#210 [threadreaderapp.com] HTML filter toggle doesn't apply until you do a force refresh

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opened 4 months ago by emlimap · 4 comments

URL: https://threadreaderapp.com/thread/1329697513830420482.html

On Thread reader website, enabling HTML doesn't make a difference until you do a force refresh. When it is broken the whole page aligns to the left as opposed to being centred.

It seems this website requires a force refresh as clicking on refresh button in the browser after enabling filter toggle doesn't fix it either.

Steps to reproduce

Visting the above URL with LocalCDN enabled but HTML filter toggle disabled. Inverted HTML filter shouldn't be enabled
Enable HTML filter
The page should refresh but remain broken due to CSS stylesheets not being injected.
If you force refresh (ctrl/cmd + f5), it works fine.

Errors from browser console.

Cross-Origin Request Blocked: The Same Origin Policy disallows reading the remote resource at moz-extension://866e6a0f-5d34-304e-b582-f09a3325cc50/resources/fontawesome/5.15.1/css/all.min.css. (Reason: CORS request not http).
Cross-Origin Request Blocked: The Same Origin Policy disallows reading the remote resource at moz-extension://866e6a0f-5d34-304e-b582-f09a3325cc50/resources/bootstrap/4.5.3/bootstrap.min.css. (Reason: CORS request not http).
Cross-Origin Request Blocked: The Same Origin Policy disallows reading the remote resource at https://cdnjs.cloudflare.com/ajax/libs/font-awesome/5.14.0/css/all.min.css. (Reason: CORS request did not succeed).
Cross-Origin Request Blocked: The Same Origin Policy disallows reading the remote resource at https://cdnjs.cloudflare.com/ajax/libs/twitter-bootstrap/4.2.1/css/bootstrap.min.css. (Reason: CORS request did not succeed).

Browser: Firefox 85.0b4
LocalCDN version: 2.5.11

Edit: Just came across this after raising this issue https://codeberg.org/nobody/LocalCDN/wiki/Home#use-cases-for-localcdn

Looks like LocalCDN can't do much with strict CORS policies.

Thank you for your detailed report.

The website uses a ServiceWorker. This is partially similar to a proxy that is between your browser and the web server. If you disable the ServiceWorker in the whole browser, the replacement works without any problems. This ServiceWorker also handles caching and blocks loading from other (even LocalCDN) sources.

If you don't need the features of a ServiceWorker (e.g. offline availability, caching or push notifications), you can simply disable it with about:config:

dom.serviceWorkers.enabled = false

I'm currently undecided whether LocalCDN should block ServiceWorker. I don't think so, because that's not really part of LocalCDN's job. But I'll add a note to the wiki soon.

https://developer.mozilla.org/en-US/docs/Web/API/Service_Worker_API
https://web.dev/service-worker-mindset/

nobody added the

sop/cors

label 4 months ago

Could a solution like https://stackoverflow.com/questions/5721704/window-location-reload-with-clear-cache be used with the auto-refresh feature in LocalCDN? Perhaps an opt-in in the settings? (It might slightly break cross-browser compatibility, and need some testing.)

It depends on what the service worker is doing. It doesn't always work as a cache. Mostly it's used for tracking or offline functionality, so it's recommended to disable this feature completely in the (Firefox) browser.

I have added the section "Service Worker" in the Wiki: https://codeberg.org/nobody/LocalCDN/wiki/Home#7-3-service-worker

nobody added the

documentation

label 4 months ago

nobody closed this issue 4 months ago

see #369 Information about SOP/CORS related issues

documentation

sop/cors

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