How to extract two slot values having time in RASA - chatbot

Question

I have a FormAction for Applying Leave which requires 3 fields
Leave_Type
Start_Date
End_Date
Now how to extract date and set appropriately in the slots. As the user input can simply be just a date value like - “12/09/2017” or “12 July 2007” or “Sept 21 2016”. The Form will prompt for each of the slot.
Duckling provides a way to enter range but for that user query should be like- "I want to apply leave from 12/2/2018 to 13/2/2018". But my bot prompts user with FormAction for each slot. So when bot asks for Start_Date the input date should be mapped to Start_Date slot

Answer 1

From what I understand, you want to extract both the start and end date slots from the same sentence if the user says something like "I want a leave from 21st September to 23rd September", and not have the bot ask for the end date again.
Since you are parsing dates and date-ranges, I recommend you include Duckling as a component in your NLU pipeline. It returns a plain string if it's a single date and a dict with from and to fields if it's a date range. So, in your action code, you could check the type of the returned entity and either fill both of the slots or just one of them.
Also, like Mukul mentioned, you will have to use slot mappings to map from the "time" entity returned by Duckling to your slots.
Your final solution will probably look something like this (I haven't included the leave type slot).
class LeaveForm(FormAction):
def name(self) -> Text:
return "leave_form"
#staticmethod
def required_slots(tracker: Tracker) -> List[Text]:
return ['start_date', 'end_date']
def validate_start_date(self,
value: Text,
dispatcher: CollectingDispatcher,
tracker: Tracker,
domain: Dict[Text, Any],
) -> Optional[Text]:
# Check if value is a Duckling date-range.
if isinstance(value, dict):
# Since both the fields are populated, the form
# will no longer prompt the user separately for the end_date
return {
'start_date': value['from'],
'end_date': value['to']
}
else:
return {
'start_date': value
}
def slot_mappings(self) -> Dict[Text, Union[Dict, List[Dict]]]:
return {
"start_date": self.from_entity(entity="time"),
"end_date": self.from_entity(entity="time")
}
def submit(self, dispatcher: CollectingDispatcher,
tracker: Tracker,
domain: Dict[Text, Any]) -> List[Dict]:
dispatcher.utter_template('utter_submit', tracker)
return []