Google Action Webhook Inline Editor Returns Before the API call

Question

This is my first Google Action project. I have a simple slot after the invocation. User enters the value on prompt and slot invokes the webhook and make a call to API using the user input. All works fine. However the webhook returns to users even before the API call finish processing and returns the value (line 1 conv.add). I do see in the logs that everything from API is logged fine after the webhook returns to user. Below is the code I am using. I am using inline editor. What am I missing? Thanks for help in advance.

const { conversation } = require('@assistant/conversation');
const functions = require('firebase-functions');
var https = require('https');
const fetch = require('node-fetch');
const app = conversation({debug: true});

app.handle('SearchData', conv => {
   
  const body = JSON.stringify({
        val: "this is my body"
    });
  
      // prepare the header
    var postheaders = {
        'Content-Type' : 'application/json',
        'Auth' : 'MyAuthCreds'
    };
 
fetch('https://host.domain.com/data', {
        method: 'post',
        body:    body,
        headers: postheaders,
    })
    .then(res => res.json())
    .then(d => {
        console.log(d);
                var profile = d;//JSON.parse(d);
            console.log(d.entries);
                console.log("Length: "+ d.entries.length);
                if(d.entries.length > 0)
                {
                    console.log("Data found");
                    conv.add("Data found"); //line 1
            }
                else
                {
                    console.log("no data found");    
                    conv.add("no data found"); //line 1
            }
    })        
    .catch(function (err) {
            // POST failed...
            console.log(err);
    });
});

exports.ActionsOnGoogleFulfillment = functions.https.onRequest(app);

Answer 1

Your issue is that your handler is making API calls which are asynchronous, but the Assistant Conversation library doesn't know that you're doing so. So as soon as the handler finishes, it tries to send back a response, but your asynchronous responses (the stuff in the then() blocks) haven't executed yet.

To address this, you need to return a Promise object so the library knows to wait till the Promise is fulfilled before it returns.

Fortunately, in your case, this should be pretty straightforward. fetch and all the .then() blocks return a Promise. So all you need to do is add a return statement in front of the call to fetch. So something like this:

return fetch('https://host.domain.com/data', {