Autocomplete custom data in Slack commands

Question

Just playing with my first slack command. Is there any way of adding custom data from an external API for autocomplete. So what works perfectly right now, is calling the command /assign plus a slack user (both will be autocompleted, nice!). What I want/need is a list of items I would fetch from a remote endpoint, which can be selected by autocomplete.

Is this possible at all?

/assign @userX to [data_by_autocomplete]

Or do I need to solve that by a full conversation like:

=> /assign user @userX
=> BOT: Which task? Here is a list: ...
=> /assign taskY
=> BOT: Assigned TaskY to @userX

But this feels very cumbersome (and wrong). So basically what I want is a remotely fetched list for autocomplete in the same command.

PS: Command and functionality is a simplified example to illustrate the point.

Answer 1

No, you can not use custom autocomplete within the command line, but you can use custom autocomplete with the the new interactive message menus.

So I would suggest to break it up into two steps.

1. Enter slash command and provide username
2. Show interactive menu with autocomplete