Catch Alls

Stealth CatchAlls are designed to handle a very common scenario within chatbots. What happens when the user says something the bot doesn't understand? The majority of bots will simply respond back with a generic "I don't understand" and hope the user to figures out the next step. While this experience might be ok for some bots, we built a more robust way of handling these experiences right into Stealth. The better your CatchAlls, the better your bot.

Triggering

A CatchAll flow is automatically triggered when a controller action fails to do at least one of the following:

1. Update a session (via step_to, update_session_to, or any other of the step methods)
2. Send a reply via send_replies

In addition to the above two conditions, if your controller action raises an Exception, the CatchAll flow will automatically be triggered.

Multi-Level

Stealth keeps track of how many times a CatchAll is triggered for a given session. This allows you to build experiences in which the user is provided different responses for subsequent failures. Once a session progresses past a failing state, the CatchAll counter resets.

Retrying

By default, a Stealth bot comes with the first level CatchAll already defined. Here is the CatchAllsController action and associated reply:

class CatchAllsController < BotController

  def level1
    send_replies

    if fail_session.present?
      step_to session: fail_session
    else
      step_to session: previous_session - 2.states
    end
  end

private

   def fail_session
     previous_session.flow.current_state.fails_to
   end

end

- reply_type: text
  text: Oops. It looks like something went wrong. Let's try that again

In the controller action, we check if the previous_session (the one that failed) specified a fails_to state. If so, we send the user there. Otherwise, we send the user back 2 states.

Sending a user back two states is a pretty good generic action. Going back 1 state takes us back to the action that failed. Since the actions most likely to fail are get actions, or actions that deal with user responses, going back 2 states usually takes us back to the original "question".

Adding More Levels

If you would like to expand the experience, simply add a level2 controller action and associated reply (and update the FlowMap). You can go as far as you want. CatchAlls have no limit, just make sure you increment using the standardized method names of level1, level2, level3, level4, etc.

If a user has encountered the maximum number of CatchAll levels as you have defined, the user's session will remain at the last CatchAll state.

Caveats

Triggering Catch-Alls within the CatchAllsController

In order to prevent infinite loops, starting in Stealth 2.0, errors raised within the catch_all flow will be ignored.