Custom Queries

In this lesson we will show you how to customise how we ask for information from the user.

Video#

Code#

Let's look at our domain.yml file again. In particular, let's zoom in on two responses.

responses:
  utter_ask_first_name:
  - text: What is your first name?
  utter_ask_last_name:
  - text: What is your last name?

The utterances that ask for a name follow a utter_ask_<slotname> convention. This is how Rasa knows how to ask for a slot value. We could take it a step further though by using a custom action instead of a static response.

Custom Action#

The naming convention for the custom action is a bit different. Instead of utter_ask_<slotname> it becomes action_ask_<slot_name> or action_ask_<form_name>_<slot_name> if we'd like to use a specific form.

So let's remove the standard utter_ask_last_name from our domain.yml file and replace it a query written as a custom action. The custom action code from the video is listed below.

from typing import Dict, Text, List

from rasa_sdk import Tracker
from rasa_sdk.events import EventType
from rasa_sdk.executor import CollectingDispatcher
from rasa_sdk import Action


class AskForSlotAction(Action):
    def name(self) -> Text:
        return "action_ask_last_name"

    def run(
        self, dispatcher: CollectingDispatcher, tracker: Tracker, domain: Dict
    ) -> List[EventType]:
        first_name = tracker.get_slot("first_name")
        dispatcher.utter_message(text=f"So {first_name}, what is your last name?")
        return []

To run this custom action we will need to update our domain.yml file so that it is aware of this new custom action.

actions:
- action_ask_last_name

Once that's done, you can retrain a new Rasa model and confirm that the form now uses a custom action to query the user. Note in order to run this you'll need to configure you endpoints.yml file first.

action_endpoint:
 url: "http://localhost:5055/webhook"

Once the new model is trained you can start a custom action service that Rasa can talk to.

rasa run actions

Links#

• GitHub repo
• Rasa Open Source Docs

Exercises#

Try to answer the following questions to test your knowledge.

1. What is the naming convention for a custom action that asks for a slot?
2. Let's say you want to use the first name to ask for a last name. Do you need to write a custom action for this use-case?