Dialogflow v2 client library not working | Error: Could not load the default credentials - google-api

Question

here is their sample code:
const dialogflow = require('dialogflow');
const uuid = require('uuid');
/**
* Send a query to the dialogflow agent, and return the query result.
* #param {string} projectId The project to be used
*/
async function runSample(projectId = 'your-project-id') {
// A unique identifier for the given session
const sessionId = uuid.v4();
// Create a new session
const sessionClient = new dialogflow.SessionsClient();
const sessionPath = sessionClient.sessionPath(projectId, sessionId);
// The text query request.
const request = {
session: sessionPath,
queryInput: {
text: {
// The query to send to the dialogflow agent
text: 'hello',
// The language used by the client (en-US)
languageCode: 'en-US',
},
},
};
// Send request and log result
const responses = await sessionClient.detectIntent(request);
console.log('Detected intent');
const result = responses[0].queryResult;
console.log(` Query: ${result.queryText}`);
console.log(` Response: ${result.fulfillmentText}`);
if (result.intent) {
console.log(` Intent: ${result.intent.displayName}`);
} else {
console.log(` No intent matched.`);
}
}
and this code is not working at all, giving Error: Could not load the default credentials :
2019-03-21T16:59:40.099101+00:00 app[web.1]: Message: hi Bilal
2019-03-21T16:59:40.102561+00:00 app[web.1]: (node:23) UnhandledPromiseRejectionWarning: Error: Could not load the default credentials. Browse to https://cloud.google.com/docs/authentication/getting-started for more information.
2019-03-21T16:59:40.102565+00:00 app[web.1]: at GoogleAuth.<anonymous> (/app/web/node_modules/google-auth-library/build/src/auth/googleauth.js:168:23)
2019-03-21T16:59:40.102568+00:00 app[web.1]: at Generator.next (<anonymous>)
2019-03-21T16:59:40.102570+00:00 app[web.1]: at fulfilled (/app/web/node_modules/google-auth-library/build/src/auth/googleauth.js:19:58)
2019-03-21T16:59:40.102572+00:00 app[web.1]: at process._tickCallback (internal/process/next_tick.js:68:7)
2019-03-21T16:59:40.102691+00:00 app[web.1]: (node:23) UnhandledPromiseRejectionWarning: Unhandled promise rejection. This error originated either by throwing inside of an async function without a catch block, or by rejecting a promise which was not handled with .catch(). (rejection id: 1)
2019-03-21T16:59:40.102784+00:00 app[web.1]: (node:23) [DEP0018] DeprecationWarning: Unhandled promise rejections are deprecated. In the future, promise rejections that are not handled will terminate the Node.js process with a non-zero exit code.
2019-03-21T16:59:55.986568+00:00 app[web.1]: Message: hi Bilal
2019-03-21T16:59:55.986595+00:00 app[web.1]: (node:23) UnhandledPromiseRejectionWarning: Error: Could not load the default credentials. Browse to https://cloud.google.com/docs/authentication/getting-started for more information.
2019-03-21T16:59:55.986598+00:00 app[web.1]: at GoogleAuth.<anonymous> (/app/web/node_modules/google-auth-library/build/src/auth/googleauth.js:168:23)
2019-03-21T16:59:55.986600+00:00 app[web.1]: at Generator.next (<anonymous>)
2019-03-21T16:59:55.986602+00:00 app[web.1]: at fulfilled (/app/web/node_modules/google-auth-library/build/src/auth/googleauth.js:19:58)
2019-03-21T16:59:55.986605+00:00 app[web.1]: at process._tickCallback (internal/process/next_tick.js:68:7)
2019-03-21T16:59:55.986647+00:00 app[web.1]: (node:23) UnhandledPromiseRejectionWarning: Unhandled promise rejection. This error originated either by throwing inside of an async function without a catch block, or by rejecting a promise which was not handled with .catch(). (rejection id: 2)
they have instructions how to use this library in the repo but it doesnt makes sense https://github.com/googleapis/nodejs-dialogflow
they have not described anywhere how to put credentials while calling detect intent, not eve in the example code here: https://github.com/googleapis/nodejs-dialogflow/blob/master/samples/detect.js
I have never seen such irresponsible team like dialogflow team in my life
Update:
exporting env variable solved my problem and now I am getting something back from dialogflow but not as expected, may be they have incorrect code in their repository sample code
this is the code they do have as try an example:
...
// Send request and log result
const responses = await sessionClient.detectIntent(request);
console.log('Detected intent');
const result = responses[0].queryResult;
console.log(` Query: ${result.queryText}`);
console.log(` Response: ${result.fulfillmentText}`);
if (result.intent) {
console.log(` Intent: ${result.intent.displayName}`);
} else {
console.log(` No intent matched.`);
}
...
and in fact result.fulfillmentText does not exist, it is giving me undefined
Update 2
that much effort I have done(see console.logs below) just to understand that instead of responses[0].queryResult.fulfillmentText now they return responses[0].queryResult.fulfillmentMessages and it is not a text string but it is an object which have further values in it that you can see in console.logs below:
...
// Send request and log result
const responses = await sessionClient.detectIntent(request);
console.log('Detected intent');
console.log("responses: ", responses)
console.log("responses[0]: ", responses[0])
console.log("responses[0].queryResult: ", responses[0].queryResult)
console.log("responses[0].queryResult.fulfillmentMessages: ", responses[0].queryResult.fulfillmentMessages)
// console.log("responses[0].queryResult.fulfillmentMessages[1]: ", responses[0].queryResult.fulfillmentMessages[1])
console.log("responses[0].queryResult.fulfillmentMessages[0]: ", responses[0].queryResult.fulfillmentMessages[0])
console.log("responses[0].queryResult.fulfillmentMessages[0].text: ", responses[0].queryResult.fulfillmentMessages[0].text)
console.log("responses[0].queryResult.fulfillmentMessages[0].text.text: ", responses[0].queryResult.fulfillmentMessages[0].text.text)
console.log("responses[0].queryResult.fulfillmentMessages[0].text.text[0]: ", responses[0].queryResult.fulfillmentMessages[0].text.text[0])
var fulfilmentText = responses[0].queryResult.fulfillmentMessages[0].text.text[0]
...

Answer 1

The google auth library is looking for an environment variable called
GOOGLE_APPLICATION_CREDENTIALS that points to a JSON credentials file.
You can download that file by following instructions as described in https://dialogflow.com/docs/reference/v2-auth-setup.
The link after the error message has examples of how to set that environment variable:
https://cloud.google.com/docs/authentication/getting-started

Answer 2

Have you tried taking a look at this? You'll need to set up authentication, create a service account key as a .json then have Google Cloud SDK handle it.
https://dialogflow.com/docs/reference/v2-auth-setup
You can also try passing in the service account like this
// Create a new session
const sessionClient = new dialogflow.SessionsClient({keyFilename: "./service_account.json"});