Action using web-fulfillment with firebase throwing MalformedResponse 'final_response' must be set

Question

Env : Using firebase cloud deployed google action. Action is using webhook to get results from functions. I am using Blaze plan so calling external URL should be legit. I am using dialogflow V2.

Part of my function's job is doing the following: I make an external API request using the following (Masked code detail):

var requestObj = require('request');
var options = {
  url: 'my url',
  headers: {
    'User-Agent': 'request'
  }
};

function callback(error, response, body) {
  if (!error && response.statusCode == 200) {
    var info = JSON.parse(body);
    result = JSON.parse(body).element;
    console.log('Title 0  ' + result);
  }
}

requestObj(options, callback);

Once I have the result, I parse it and use it.

Following are my reference points that I tried from stack overflow solutions:

• Dialogflow v2 API + Actions v2 API: MalformedResponse 'final_response' must be set

Would appreciate any help from the community.

Answer 1

In most cases involving the MalformedResponse and an asynchronous call using something like request, the problem is that you're sending the response outside of the callback. Frequently this is because the library is expecting a Promise and you are handling things in a non-promise like way.

My usual practice is:

• use the request-promise library (or the request-promise-native library)
• in one of the then sections where you get the results, make sure you call conv.ask()
• make sure you return the promise itself.

So (very roughly)

var request = require('request-promise-native');

var options = {
  uri: 'https://example.com/api',
  json: true // Automatically parses the JSON string in the response
};

return request(options)
  .then( response => {
    // The response will be a JSON object already. Do whatever with it.
    var value = response.whatever.you.want;
    return conv.ask( `The value is ${value}. What now?` );
  });