Client-tag for specifying in which shared channel a private NOTICE should be displayed

[delthas]

Many IRC bots respond to commands in a channel with a private NOTICE.

>>> PRIVMSG #foo :!help
<<< :bot NOTICE me :i can't help

This is a common practice that is done to prevent flooding a channel with messages that are only useful to a single user. But there is no way for the client to actually know that this message was meant to be sent as a response to a query in #foo.

Most clients have developed heuristics to match incoming NOTICEs with a corresponding channel context that makes the most sense. In some clients this is built-in, in some others these are third-party scripts.

The usual order in which these channels are matched with these heuristics is typically:

• the current channel shown in the client, if the sender is in that channel
• a channel in which the sender is present (this could be the last opened channel in the client, the first one by order, the last one in which the client sent a message, ...)
• optionally, the current channel even if the bot is not in it
• an actual private buffer with the sender

This is a bit of a hack and is a bit harder to work with on clients that use CHATHISTORY and do not necessarily have a "client context" (which buffer did we open last at the time of receiving) at hand. eg if I connect after 1 week to my bouncer and run CHATHISTORY, my heuristic may not return the same result as if I had just received the message "live".

Now that we have client-only tags, we could make the bot send the actual channel the message refers to, in a client-only tag. This is a client-only tag because it does not require any processing from the server. Client-only tags are blacklisted from some servers/networks, but this is fine because it is a best-effort piece of information.

>>> PRIVMSG #foo :!help
<<< @+channel=#foo :bot NOTICE me :i can't help

The heuristic now becomes:

• the channel specified in the channel tag, if the sender and the client are in that channel
• ... (the usual other heuristics)

There is no particular security issue (as long as the client checks that the sender is indeed in the channel it pretends to refer a message to).

The actual tag name is open to discussion. A short list:

• +channel
• +channel-context

Thoughts?

Relates to/closes: #163

[progval]

On networks which support it, you can use CPRIVMSG/CNOTICE (aka WHISPER) for this: https://github.com/evilnet/nefarious2/blob/master/doc/features.txt#L89

[grawity]

On networks which support it, you can use CPRIVMSG/CNOTICE (aka WHISPER) for this: https://github.com/evilnet/nefarious2/blob/master/doc/features.txt#L89

CNOTICE is not the same thing as WHISPER; it only affects server-side rate limits – the additional context parameter is invisible to the recipient, they just get a regular NOTICE with no context. (Besides that, you need to be a chanop to use it.)

An actual IRCX WHISPER command that is visible to recipients would be great, but every time it comes up, someone says "use a tag instead".

[progval]

I see, thanks

[ailin-nemui]

There is a WHISPER emulation by convention, used by ChanServ and supported in Irssi through /set notice_channel_context, whereas the bot has to send "[#channel] text" in its reply

[jwheare]

PR here #498