1641998 - Add an intervention for Twitter videos that have cookies blocked

Status: RESOLVED FIXED

(Web Compatibility :: Interventions, task, P1)

Description

[Steven Englehardt [:englehardt]]

Embedded Twitter videos are currently broken by ETP's cookie blocking. See Bug 1641521 as an example. These video embeds are incredibly common on news sites, so it's likely that this breakage is widespread beyond the two publishers mentioned in that bug. This breakage is present both on Fenix and Desktop.

We've shipped an anti-tracking intervention which unblocks the video path from cookie blocking, but this also exposes users to tracking from Twitter. Thankfully, resources from the unblocked path only seems to load after user interaction. Bug 1641969 tracks that intervention.

However, it would be better to ship an intervention via the webcompat addon since it means we won't have to unblock cookies from that origin. I dug into why the videos are broken in Bug 1641521 Comment 3 and prototyped a fix here https://github.com/englehardt/twitter-video-fix which seems to work, but I only tested on a couple sites. We should confirm that it works with and without ETP enabled and test a few more news sites. We should also test twitter videos when visiting twitter as a first party.

Comment 1

[Dennis Schubert [:denschub]]

Hey Steven,

is there a way to test an intervention without the skiplisting tracked in bug 1641969? I tried emptying the urlclassifier.features.socialtracking.annotate.* prefs and related prefs in the urlclassifier.features. tree, but I can't seem to break embedded twitter videos. Is there a magic pref or something else I have to do?

Comment 2

[Steven Englehardt [:englehardt]]

(In reply to Dennis Schubert [:denschub] from comment #1)

Hey Steven,

is there a way to test an intervention without the skiplisting tracked in bug 1641969? I tried emptying the urlclassifier.features.socialtracking.annotate.* prefs and related prefs in the urlclassifier.features. tree, but I can't seem to break embedded twitter videos. Is there a magic pref or something else I have to do?

Yes there is.

Unfortunately we don't yet have an easy way to disable the skiplist served through remote settings (Bug 1644273 will add something for that).

Until then you'll have to follow these steps:
1. Use a fresh Firefox browser profile
2. Install the RemoteSettings devtools extension [0]
3. Click the Remote Settings devtools icon that's added to the browser's toolbar after installation
4. Under "Sync actions" click "Clear ALL local data"
5. Restart the browser
[0] https://github.com/mozilla-extensions/remote-settings-devtools/releases/download/1.2.1/[e-mail]

EDIT: It looks like those steps don't work anymore. I forgot we preload the collection. These will work instead.

1. Use a fresh Firefox browser profile.
2. Go to about:config.
3. Change services.settings.default_bucket from main to foo.
4. Restart the browser.

Comment 3

[Steven Englehardt [:englehardt]]

Dennis, FYI I've updated the comment above with the correct steps

Comment 4

[Dennis Schubert [:denschub]]

Attachment: GitHub Pull Request

Awesome, thanks!

I could test that the solution you suggested works fine, and I tested on some news sites and on isolated embeds, and it appears to work fine without any downside.

I added the intervention in the PR linked above. Landing this change will be tracked in bug 1637672, and I plan on landing it today or tomorrow.