DialogflowSDK middleware return after resolving a promise - google-cloud-functions

Question

I'm currently playing around with the actions-on-google node sdk and I'm struggling to work out how to wait for a promise to resolve in my middleware before it then executes my intent. I've tried using async/await and returning a promise from my middleware function but neither method appears to work. I know typically you wouldn't override the intent like i'm doing here but this is to test what's going on.
const {dialogflow} = require('actions-on-google');
const functions = require('firebase-functions');
const app = dialogflow({debug: true});
function promiseTest() {
return new Promise((resolve,reject) => {
setTimeout(() => {
resolve('Resolved');
}, 2000)
})
}
app.middleware(async (conv) => {
let r = await promiseTest();
conv.intent = r
})
app.fallback(conv => {
const intent = conv.intent;
conv.ask("hello, you're intent was " + intent );
});
It looks like I should at least be able to return a promise https://actions-on-google.github.io/actions-on-google-nodejs/interfaces/dialogflow.dialogflowmiddleware.html
but I'm not familiar with typescript so I'm not sure if I'm reading these docs correctly.
anyone able to advise how to do this correctly? For instance a real life sample might be I need to make a DB call and wait for that to return in my middleware before proceeding to the next step.
My function is using the NodeJS V8 beta in google cloud functions.
The output of this code is whatever the actual intent was e.g the default welcome intent, rather than "resolved" but there are no errors. So the middleware fires, but then moves onto the fallback intent before the promise resolves. e.g before setting conv.intent = r

Answer 1

Async stuff is really fiddly with the V2 API. And for me only properly worked with NodeJS 8. The reason is that from V2 onwards, unless you return the promise, the action returns empty as it has finished before the rest of the function is evaluated. There is a lot to work through to figure it out, here's some sample boilerplate I have that should get you going:
'use strict';
const functions = require('firebase-functions');
const {WebhookClient} = require('dialogflow-fulfillment');
const {BasicCard, MediaObject, Card, Suggestion, Image, Button} = require('actions-on-google');
var http_request = require('request-promise-native');
process.env.DEBUG = 'dialogflow:debug'; // enables lib debugging statements
exports.dialogflowFirebaseFulfillment = functions.https.onRequest((request, response) => {
const agent = new WebhookClient({ request, response });
console.log('Dialogflow Request headers: ' + JSON.stringify(request.headers));
console.log('Dialogflow Request body: ' + JSON.stringify(request.body));
function welcome(agent) {
agent.add(`Welcome to my agent!`);
}
function fallback(agent) {
agent.add(`I didn't understand`);
agent.add(`I'm sorry, can you try again?`);
}
function handleMyIntent(agent) {
let conv = agent.conv();
let key = request.body.queryResult.parameters['MyParam'];
var myAgent = agent;
return new Promise((resolve, reject) => {
http_request('http://someurl.com').then(async function(apiData) {
if (key === 'Hey') {
conv.close('Howdy');
} else {
conv.close('Bye');
}
myAgent.add(conv);
return resolve();
}).catch(function(err) {
conv.close(' \nUh, oh. There was an error, please try again later');
myAgent.add(conv);
return resolve();
})})
}
let intentMap = new Map();
intentMap.set('Default Welcome Intent', welcome);
intentMap.set('Default Fallback Intent', fallback);
intentMap.set('myCustomIntent', handleMyIntent);
agent.handleRequest(intentMap);
});
A brief overview of what you need:
you have to return the promise resolution.
you have to use the 'request-promise-native' package for HTTP requests
you have to upgrade your plan to allow for outbound HTTP requests (https://firebase.google.com/pricing/)

Answer 2

So it turns out my issue was to do with an outdated version of the actions-on-google sdk. The dialogflow firebase example was using v2.0.0, changing this to 2.2.0 in the package.json resolved the issue