Add a new filter option $message for strict blocking

[Yuki2718]

Prerequisites

• I verified that this is not a filter issue
  • Filter issues MUST be reported at filter issue tracker
• This is not a support issue or a question
  • Support issues and questions are handled at /r/uBlockOrigin
• I performed a cursory search of the issue tracker to avoid opening a duplicate issue
  • Your issue may already be reported.
• I tried to reproduce the issue when...
  • uBlock Origin is the only extension
  • uBlock Origin with default lists/settings
  • using a new, unmodified browser profile
• I am running the latest version of uBlock Origin
• I checked the documentation to understand that the issue I report is not a normal behavior

Description

I'm impressed with clever use of $domain= by @DandelionSprout DandelionSprout/adfilt#81 (comment), however, in this case you can't use $domain for its original purpose. This can be significant disadvantage as those rules for bad domains can well be untokenizable regex rules which should be narrowed down by $domain. So my proposal here, add $message (or whatsoever suitable English word) to show messages on the strict-blocked page.
Ex.
||badsite.com^$message="The site is blocked for phishing activity!"

Correct me if I'm wrong but I believe this option can and should be ignored on filter parsing - strict-blocked page shows original list name, which means reverse-lookup was done so why doesn't fetch the value of this new option at this step. I wonder if @curbengh, in addition to @DandelionSprout of course, has interest in using this if it's adopted. Other than bad domains, I will use this option for links with tracking parameter. Most users of my lists would have no idea about what to do if such a link is blocked and all my experiences tell that explaining that (i.e. clicking a loupe icon to get a non-tracking link) in README is far from enough.

A specific URL where the issue occurs

Really any URL that can be strict-blocked, but e.g. http://rsalcau.com/ as it's blocked by EL.

Steps to Reproduce

Skipping

Expected behavior:

Messages can be shown on strict-blocked page

Actual behavior:

There's no way other than exploiting $domain=.

Your environment

• uBlock Origin version: 1.28.4
• Browser Name and version: Firefox 79.0
• Operating System and version: Windows 10

[DandelionSprout]

I see what you're thinking of, and I thank you for the compliments, but if I'm not wildly mistaken, it already can be used for its original purpose. E.g. ||example.org^$domain=example.com|~ Warning comment text.

[Yuki2718]

I see what you're thinking of, and I thank you for the compliments, but if I'm not wildly mistaken, it already can be used for its original purpose. E.g. ||example.org^$domain=example.com|~ Warning comment text.

Okay, I didn't know that. I still can't fully desert the idea of a dedicated option until declined, or unless uBO team guarantees there can be no detrimental effects in using domain option even with 16 bytes char such as 広告.

[DandelionSprout]

Now that you mention it, the $domain trick currently has zero support for non-ASCII letters, or for commas. So that (Especially the former) is one thing that could theorethically be supported and improved on in $message.

[gorhill]

Trying to support messages is quite a task, let alone localized messages.

[curbengh]

@Yuki2718
Most users of my lists would have no idea about what to do if such a link is blocked

My understanding of this suggestion is that it can help user (and maintainer) of a merged blocklist (e.g. Energized Protection) to identify the upstream source of a filter, so that it's easy for them to report issue.

For my end, it's trivial for me to create a new blocklist with $message suffix, so I don't mind.

[Yuki2718]

Trying to support messages is quite a task, let alone localized messages.

Then how about a new special comment, in addition to currently supported "! Title:" etc., one special comment for strict blocking per one list. Not as flexible as the original proposal (I'll need to list up all the possible reason, but for a dedicated anti-malware list it won't be a big issue) but given localized titles are correctly displayed, I guess this will solve the localization matter.

Ex.

! Homepage: http://example.com/
! Title: Foo Anti-phishing List
! Expires: 5 days
! Block-message: The site was blocked for phishing activity.

Maybe it can be loaded with Title but not shown as a title, instead only seen in a strict-blocked page with/under the title currently shown.

@curbengh Thx for the valuable comment, that's what I couldn't think of. My new suggestion above may not support this use case in merged lists, but anyway @gorhill will know what's the best to balance between time to spend and the benefit by the enhancement. Nice to know you can utilize the new option if adopted.

[gorhill]

identify the upstream source of a filter

The list(s) containing the filter is already reported in the document-blocked page.

[gorhill]

! Title: Foo Anti-phishing List
! Expires: 5 days
! Block-message: The site was blocked for phishing activity.

I don't see the message adding useful information, the title of the list is already telling us that the page was blocked because of a filter in "Foo Anti-phishing List".

[Yuki2718]

Uh, yes, in this case. And admittedly explaining all the cases in that way in a general list will not be trivial and may possibly confuse user.

[curbengh]

#1195 (comment)
identify the upstream source of a filter

I meant in a merged list, say I combine blocklists X and Y

! Title: Combined Blocklist
||badsite1.com^$message="Blocklist X"
||badsite2.com^$message="Blocklist Y"

then uBO can show "Combined Blocklist" and "Blocklist X" when a filter is triggered.

Currently blocklist maintainer could add a comment:

! Title: Combined Blocklist

! Blocklist X
||badsite1.com^

! Blocklist Y
||badsite2.com^

This way, maintainer still can easily find the source of a filter, user could also do it via "view content"; my understanding (could be different from OP's) of this $message suggestion is that uBO can directly show the source instead.

Personally, I find ! Blocklist X approach is sufficient though and it hardly increase the file size of a merged blocklist.

[krystian3w]

Reddit idea to block malware pages with diffrent pop-up and have another switch:

https://old.reddit.com/r/uBlockOrigin/comments/k1yyf7/feature_idea_feedback/

[Yuki2718]

Somehow I can't find with cursory search but IIRC there was similar suggestion on Github (or maybe I'm just confusing something).