Mattermost, Inc.

Slash commands and Microsoft Flow


Anyone has slash commands running successfully with Microsoft Flow? I can get Flow to process outgoing webhooks just fine, but slash commands not. The problem seems to be that Mattermost includes Authorization header in the slash command, which Flow does not like and answers with 401. The Flow behaviour is not configurable and exactly the same Flow workflow is working fine when called from a webhook.

To the user Mattermost shows “Command with a trigger of ‘commandname’ returned response 401 Unauthorized” and logs the Flow response:

“http_code”:500,“err_details”:"{“error”:{“code”:“DirectApiAuthorizationRequired”,“message”:“The request must be authenticated only by Shared Access scheme.”

By the way, it’s completely stupid that outgoing webhooks cannot be used on private channels. That’s the only reason to even attempt using slash commands in this case…