Dialogflow-fulfillment-nodejs: TypeError: Cannot read property 'ask' of null

[kwizfreak]

I have this code and i have this error :

TypeError: Cannot read property 'ask' of null

/**

• Copyright 2017 Google Inc. All Rights Reserved.
  *
• Licensed under the Apache License, Version 2.0 (the "License");
• you may not use this file except in compliance with the License.
• You may obtain a copy of the License at
  *
• http://www.apache.org/licenses/LICENSE-2.0
  *
• Unless required by applicable law or agreed to in writing, software
• distributed under the License is distributed on an "AS IS" BASIS,
• WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
• See the License for the specific language governing permissions and
• limitations under the License.
  */

'use strict';

const express = require("express");
const bodyParser = require("body-parser");
const { WebhookClient } = require('dialogflow-fulfillment');
const { Card, Suggestion } = require('dialogflow-fulfillment');
const { Carousel } = require('actions-on-google');

process.env.DEBUG = 'dialogflow:debug'; // enables lib debugging statements

const restService = express();
const request = require('request-promise-native');
const app = actionssdk();

restService.use(
bodyParser.urlencoded({
extended: true
})
);

restService.use(bodyParser.json());

restService.post("/echo", function(req, res) {

const imageUrl = 'https://developers.google.com/actions/images/badges/XPM_BADGING_GoogleAssistant_VER.png';
const imageUrl2 = 'https://lh3.googleusercontent.com/Nu3a6F80WfixUqf_ec_vgXy_c0-0r4VLJRXjVFF_X_CIilEu8B9fT35qyTEj_PEsKw';
const linkUrl = 'https://assistant.google.com/';
const agent = new WebhookClient({ request: req, response: res });
console.log('Dialogflow Request headers: ' + JSON.stringify(request.headers));
console.log('Dialogflow Request body: ' + JSON.stringify(request.body));
let intentMap = new Map();
intentMap.set('Default Welcome Intent', welcome);
intentMap.set('Default Fallback Intent', fallback);

agent.handleRequest(intentMap);
});

function welcome(agent) {
let conv = agent.conv();
// Use Actions on Google library to add responses
conv.ask('Please choose an item:')
conv.ask(new Carousel({
title: 'Google Assistant',
items: {
'WorksWithGoogleAssistantItemKey': {
title: 'Works With the Google Assistant',
description: 'If you see this logo, you know it will work with the Google Assistant.',
image: {
url: imageUrl,
accessibilityText: 'Works With the Google Assistant logo',
},
},
'GoogleHomeItemKey': {
title: 'Google Home',
description: 'Google Home is a powerful speaker and voice Assistant.',
image: {
url: imageUrl2,
accessibilityText: 'Google Home',
},
},
},
}))
// Add Actions on Google library responses to your agent's response
agent.add(conv);
}

function fallback(agent) {
let conv = agent.conv();
// Use Actions on Google library to add responses
conv.ask('Please choose an item:')

// Add Actions on Google library responses to your agent's response
agent.add(conv);
}

restService.listen(process.env.PORT || 5001, function() {
console.log("Server up and listening :) !");
});

[jorgecasar]

Check in your package.json that you have last version "dialogflow-fulfillment": "^0.3.0-beta.3".

Try with npm i --save dialogflow-fulfillment@latests.

[ashwinbalajir]

i was also having similar issue. Dont test with dialog flow inbuilt try it now. Test it with google assistant .It will work.

[jorgecasar]

Sure, agent.conv() only works for Actions on Google (Google Assistant).

Take a look the code:
https://github.com/dialogflow/dialogflow-fulfillment-nodejs/blob/master/src/dialogflow-fulfillment.js#L391-L397

[matthewayne]

Duplicate of #28

[ychen98]

Like jorgecasar pointed out, you need to set the agent.requestSource, otherwise, agent.conv() return null
const agent = new WebhookClient({ request, response });
agent.requestSource = agent.ACTIONS_ON_GOOGLE;
then agent.conv() would not return null

[valeadami]

What about dialogflow-webhook? Is there any way to end conversation by webhook without "set this intent as end of conversation"? I mean: I would like to find a way to close the conversation programmatically, i.e.
agent.endConversation_ = true;
when the user says specific utterances (for example, "stop", "end" etc).

[jorgecasar]

Yes with agent.end() instead of adding.add()

[valeadami]

ok, so if i got it right, that would end the current session, but it won't emit a sound like in actions-on-google, right?

[xscharlie]

i was also having similar issue. Dont test with dialog flow inbuilt try it now. Test it with google assistant .It will work.

Thanks, it worked for me!