Matterbridge: [feature] allow Slack @usergroups to be parsed as human-friendly names

[patcon]

We accomodate Slack !variables like @here and @channel (Related: ), but @usergroups are currently unhandled. Should be simple. Creating stub to track for later.

Docs: https://api.slack.com/docs/message-formatting#variables

[42wim]

Probably added support for this (can't test it myself, needs a paid plan it seems?), please try the latest binaries at https://bintray.com/42wim/nightly/Matterbridge/v1.8.0-29-g0bc9c70#files

Also, there has been a lot of code refactoring, which could've triggered old bugs

[patcon]

Ah, pushed the new binaries (nice logs!), but seems it's still not working: https://imgur.com/JWuXypq

Hm.. i recalled how the old parsing worked, but I'll have to catch up on refactored code and see if i can make sense of what's happening. Thanks for trying @42wim!

EDIT: Can you re-open if it's still standing?

[patcon]

ok, so it seems that we should be working in replaceVariable not replaceMention groups show in UI as starting with "@", but they are actually "!" variables.

https://github.com/42wim/matterbridge/blob/master/bridge/slack/slack.go#L364

This regex seems to do the trick: <!((?:subteam\^)?[a-zA-Z0-9]+)(?:\|(.+?))?>

Can test it here with these strings:
https://regex101.com/

<!here>
<!channel|channel>
<!subteam^S012345|happy-peeps>

There are two captured groups, which represent "command" and "label". The Slack docs say "use the label when it's there, and otherwise fall back on command string" (for backward compat).

[42wim]

So in your screenshot there is no label ? so what should it return ? @subteam^S517M0H29 ?

[patcon]

Hm. I think that change in 0bc9c70 might have actually introduced a regression:

Going back to v1.8.0

[patcon]

So in your screenshot there is no label ? so what should it return ? @subteam^S517M0H29 ?

The groups won't ever exist across instances, so best to just copy to label from <!command|label> format and prefix it with "@".

Also, to clarify, the screenshots are not showing label because the existing replaceVariable command just pulls out the "command" portion of <!command|label> from the underlying markup going over the wire. This works fine for <!here|here> and <!channel|channel>, but not <!subteam^S517M0H29|steering-committee>

[patcon]

Not sure about the regression, but this should fix the original variable replacement

// @see https://api.slack.com/docs/message-formatting#variables
func (b *Bslack) replaceVariable(text string) string {
    results := regexp.MustCompile(`<!((?:subteam\^)?[a-zA-Z0-9]+)(?:\|(.+?))?>`).FindAllStringSubmatch(text, -1)
    for _, r := range results {
        // pls doublecheck -- i don't know golang!
        name, isset := r[2]
        if !isset {
            name = r[1]
        }
        text = strings.Replace(text, r[0], "@"+name, -1)
    }
    return text
}

[42wim]

@patcon can you test https://bintray.com/42wim/nightly/Matterbridge/v1.8.0-32-g79c4ad5#files ?

[patcon]

Unfortunately the regression still exists:

Confirmed that going back to v1.8.0 resolved

Logs: https://gist.github.com/patcon/1b2010f2266f098ef1881e4c41449560

[patcon]

Also, confirmed that usergroups are suffering same issue of identifier being used instead... hm..

I'll create a new ticket for regression, as I feel that will confuse this issue until resolved :)

[patcon]

Re: https://github.com/42wim/matterbridge/issues/384#issuecomment-370541059

Related to the extra "@" in the usergroup labels (which seems to be undocumented?), this regex should address it:
<!((?:subteam\^)?[a-zA-Z0-9]+)(?:\|@?(.+?))?>

[42wim]

Ok, thanks for looking into the regex so that I didn't have to :-)
The binary is building, will be in https://bintray.com/42wim/nightly/Matterbridge/v1.8.0-39-ab94b5c#files in a couple of minutes

[patcon]

Confirmed working great now :tada: