Create actions-on-google object from Express request

Question

The documentation here shows this code example for creating an Actions SDK object for Express:

const express = require('express');
const bodyParser = require('body-parser');

const expressApp = express().use(bodyParser.json());
expressApp.post('/fulfillment', app);
expressApp.listen(3000);

But I need to do something like this:

const express = require('express');
const bodyParser = require('body-parser');

function func (req, res) {
    let headers = req.headers;
    let body = req.body;

    console.log(headers);
    console.log(body);

    const app = actionssdk({
        // init: () => body
        // init: () => req
    });

    app.intent('actions.intent.MAIN', (conv) => {
        conv.ask("Welcome to the app");
    })
    return app;
}

const expressApp = express().use(bodyParser.json());
expressApp.post('/fulfillment', func);
expressApp.listen(3000);

This obviously isn't the correct syntax and it doesn't return any response to the Google Action.

The reason I want to do something like this is to initialize the actionssdk object with dynamic clientId. I can extract the projectId from the authorization header present in req.headers object. From the projectId I can dynamically fetch the clientId and initialize the actionssdk by passing the clientId

What would be the correct syntax for this?

Answer 1

The app variable can be called with express request and response objects like so, as it is a function:

const express = require('express');
const bodyParser = require('body-parser');

const expressApp = express().use(bodyParser.json());
expressApp.post('/fulfillment', async (req, res) => {
  const clientId = // Some logic to get client ID
  const app = actionssdk({ clientId })
  // Define intent handlers here
  return app(req, res)
});
expressApp.listen(3000);