Add $cookie modifier support

[superlex]

Prerequisites

• I verified that this is not a filter list issue. Report any issues with filter lists or broken website functionality in the uAssets issue tracker.
• This is NOT an issue with YouTube, Facebook or Twitch.
• This is not a support issue or a question. For support, questions, or help, visit /r/uBlockOrigin.
• I performed a cursory search of the issue tracker to avoid opening a duplicate issue.
• The issue is not present after disabling uBO in the browser.
• I checked the documentation to understand that the issue I am reporting is not normal behavior.

I tried to reproduce the issue when...

• uBO is the only extension.
• uBO uses default lists and settings.
• using a new, unmodified browser profile.

Description

As of now uBO doesn't support $cookie modifier:
https://github.com/gorhill/uBlock/wiki/Static-filter-syntax#extended-syntax

It could be useful to prevent a cookie from being set:
AdguardTeam/AdguardFilters@236ee4d

According to AdGuard KB,

The $cookie modifier completely changes rule behavior. Instead of blocking a request, this modifier makes AdGuard suppress or modify the Cookie and Set-Cookie headers.

https://adguard.com/kb/it/general/ad-filtering/create-own-filters/#cookie-modifier

Original AG issue:
AdguardTeam/AdguardBrowserExtension#961

A specific URL where the issue occurs.

everywhere

Steps to Reproduce

Add to user filters list

example.org##+js(set-cookie, examplecookie , 1)
$cookie=examplecookie,domain=example.org

Expected behavior

examplecookie cookie isn't set.

Actual behavior

examplecookie cookie is set.

uBO version

1.53

Browser name and version

Firefox 119

Operating System and version

macOS 11

[gorhill]

I consider the best way to deal with such filter option is through the browser.cookies API, but adding such permissions would trigger a new extension permissions warning, leading to a lot of unhappy people. Implementing this through the webRequest API requires enabling a specific API capabilities, but it comes with a lot of warnings, including about performance concerns, see https://developer.chrome.com/docs/extensions/reference/webRequest/, search for opt_extraInfoSpec:

Specifying 'extraHeaders' in opt_extraInfoSpec may have a negative impact on performance, hence it should only be used when really necessary.

So I will keep the issue opened, but as of now it's unlikely I will go through with it.

Related issue: #2552

[iam-py-test]

I consider the best way to deal with such filter option is through the browser.cookies API, but adding such permissions would trigger a new extension permissions warning, leading to a lot of unhappy people.

What about an optional permission and a setting, ie

Thanks

[superlex]

Thanks anyway :)

[superlex]

@gorhill

Something like a scriptlet cookie-defuser / prevent-cookie ?

See mapx- workaround:
uBlockOrigin/uAssets@bc3b6b7

[ghost]

What about an optional permission and a setting, ie

The great majority of people would understand this as Allow uBlock Origin to block cookie notices/popups. The average user doesn't know what a cookie actually is.