Webhooks for slot filling

Question

I am having trouble with slot/parameter filling in dialogflow. I am not able to search any good documentation for how to use webhooks/backend-code for parameter filling.

My use case is, I want to extract date but if the user is not providing YEAR then it should ask the user "which year?". And then fill it back in date.

I am using $date.partial as value so it is giving UUUU for the year part, but how can I prompt the user to give the year so that I can fill it in the parameter to get complete date.

Any help is appreciated.

Answer 1

Sometimes setting a param as required is not enough, because you don't only need that param to be present, but you need it in a specific format, there's an alternative using events.

There are multiple steps, but once you're familiar with it, you'll do it very fast.

1) Create 2 new intents: Year - Confirmation & Year - Confirmed

2) Add an event in the first intent: Intent > Events > ask-year (or whatever name you like)

3) Add an output context: year-confirmation

4) Set a response asking the user to enter the year: Please provide the year...

5) Set parameter:

• Name: date
• Entity: -
• Value: #ask-year.date (This will come from event data, you will send it from your backend)

6) On your second intent Year - Confirmed, add as input context: year-confirmation (the output from the previous intent)

7) Set the same action as your main intent: insurance

8) Add some training phrases where you can match the year:

• 2017 (@sys.number:year)
• The year is @sys.number:year (Use template mode for this one)

Now you will have $year as params.

9) Add one extra parameter:

• Name: date
• Entity: -
• Value: #year-confirmation.date (This will come from year-confirmation context)

10) On your backend, when you receive the incompleted date you should send ask-year event.

Node.js example, I don't know python

const apiai = require('apiai');
const client = apiai('my-dev-token');

function sendEvent(data) {

    const request = client.eventRequest(data, {
        sessionId: 'current-session'
    });

    request.on('response', response => {
        // Push message to your UI
        console.log(response.result.fulfillment.speech); // Please provide the year...
    });

    request.on('error', error => {
        console.error('Event error: ', error);
    });

    request.end();

}

/* ... */

// Your insurance action handler
function insuranceHandler(result) {

    const { parameters } = result;

    if(parameters.date || parameters.date.includes('UUUU')) { // Or whatever check for invalid year

        // Send previous date as data, so you will have it in the event response
        return sendEvent({
            name: 'ask-year',
            data: {
                date: parameters.date
            }
        });

    }

    // Year comes from `ask-year` intent
    if(parameters.year)
        parameters.date = parameters.date.replace('UUUU', parameters.year);

    // Do whatever you need
}

Now when the date is incomplete, the event will be triggered, executing Year - Confirmation and you will be asked to provide the year. After you provide one, Year - Confirmed intent will be executed by your response. Now your backend will receive the insurance action with an additional parameter, year