Support Slack's Interactivity Mode & Block Kit

[dimasmamot]

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I am...

• Reporting a bug
• Suggesting a new feature
• Requesting help with running my bot
• Requesting help writing plugins
• Here about something else

I am running...

• Errbot version:5.2.0
• OS version: linux
• Python version: 3.6
• Using a virtual environment: yes

Issue description

The new block kits add more possible interactivity between users and bots, yet to enable the interactive mode you need to supply endpoint to receive the POST and processing all the thing that get sent to this endpoint whenever user interact with interactive component, it all has nice explanation detail in this docs https://api.slack.com/messaging/interactivity

Is it possible for errbot slack backend to implement this as a wrapper to cover the interactivity instead of creating your own endpoint and provision a special server to host the endpoint ?

I've seen this request too https://github.com/errbotio/errbot/issues/794 and I think slack did some change to their button with interactivity.

By far, did this possible for errbot to support this slack interactivity option ? That would be nice addition to errbot feature.

Additional info

It's my first request of feature, please guide me

[nzlosh]

The slack backend provides a thin wrapper to the slack webclient. The method is called api_call and can be used to call on features that aren't directly exposed through errbot's framework. https://github.com/errbotio/errbot/blob/f63019800cbb1d28f00cc1d1c98204e18925c3ec/errbot/backends/slack.py#L356

[sijis]

Transferring if there's a need for something more formal.