User.js: investigate: site exceptions Maintain Offline Storage

[Thorin-Oakenpants]

Maintain Offline Storage is a site permission. It used to be in the preferences UI, but was dropped in FF46. You now get to it per site via urlbar info icon > Right Arrow > More Information > Permissions

• Clarify just WTF is this meant to control. The default setting (regardless of prefs for various storage items) seems to be "Always Ask"
• Is there a way to make the default "block", and then users can apply site overrides for allow?
• When a site has this blocked, there is a plain square icon with a stroke thru it in your urlbar next to the info icon. If you mouse over, it says "You have blocked data storage for this site". If you click that icon, you get an option to undo the block (which sets the permission back to default)
• Weird fact: in playing around with this, google.com always showed a blocked-data-storage icon and the permissions when I looked them up were always "default". But as soon as I clicked unblock, now the only way to get google.com to block-data-storage is to override in permissions. Sorcery!
• Update on above bullet point. I haven;t cleaned out my site permissions for like 2.5 years since I did a clean profile. It was probably an old site permission hanging around - I will of course check it out in a nilla FF. NotSorcery!?

Relevant discussion: https://www.wilderssecurity.com/threads/firefox-and-indexeddb.395113/

This is meant to control indexedDB as far as I know (and it has said that in the user.js since the start over 2 years ago). As per the above link, user summerheat said that toggling this site pref made no difference (something about some content on New York Times is not shown when indexedDB is off, but shows when indexedDB is on).

We should replicate this test, and confirm in a vanilla Firefox. First, find a test page where a) with indexedDB=true we see the stuff, and b) after clearing cache with indexedDB=false we don't see the stuff and c) clear cache and do a site exception

Maybe @zymase can tell us a website, since he toggles this pref a lot. Personally, I think this is broken.

[2glops]

https://www.nextinpact.com/news/104602-windows-10-s-ses-capacites-et-restrictions-en-11-questions.htm

IndexedDB enabled = see comments under the article
IndexedDB disabled = don't see comments
IndexedDB disabled + site permission allow = still don't see comments

[Thorin-Oakenpants]

@2glops Excellent. I haven't looked at it, will do tomorrow. Have run out of time.

PS: I assume you cleared the cache between tests?

[2glops]

Yes, cache cleared.

[2glops]

https://blog.nightly.mozilla.org/2017/07/17/preview-storage-api-in-firefox-nightly/

Preview Storage API lands in Nightly
Just in time !

[earthlng]

FYI: eCleaner cleans indexedDB

FYI: eCleaner definitely does not clean indexedDB in Firefox at the moment!

https://developer.mozilla.org/en-US/Add-ons/WebExtensions/API/browsingData/remove#Browser_compatibility

Firefox does not support removal of: 'fileSystems', 'indexedDB', 'localStorage', or 'serverBoundCertificates'