actions-on-google api.ai doesn't send body in POST request with nodejs and express

Question

I'm trying to run the sillyNameMaker example from actions-on-google with api.ai, on my computer. I set up a nodejs server with express, and a ngrok tunneling. When I try to send a request with my agent on api.ai, my server receives the POST request, but the body appears to be empty. Is there anything i didn't set up properly?

Here is my index.js file:

'use strict';
var express = require('express')
var app = express()
const ApiAiAssistant = require('actions-on-google').ApiAiAssistant;

function sillyNameMaker(req, res) {
  const assistant = new ApiAiAssistant({request: req, response: res});

  // Create functions to handle requests here
  const WELCOME_INTENT = 'input.welcome';  // the action name from the API.AI intent
  const NUMBER_INTENT = 'input.number';  // the action name from the API.AI intent
  const NUMBER_ARGUMENT = 'input.mynum'; // the action name from the API.AI intent

  function welcomeIntent (assistant) {
    assistant.ask('Welcome to action snippets! Say a number.');
  }

  function numberIntent (assistant) {
    let number = assistant.getArgument(NUMBER_ARGUMENT);
    assistant.tell('You said ' + number);
  }

  let actionMap = new Map();
  actionMap.set(WELCOME_INTENT, welcomeIntent);
  actionMap.set(NUMBER_INTENT, numberIntent);
  assistant.handleRequest(actionMap);

  function responseHandler (assistant) {
    console.log("okok")
    // intent contains the name of the intent you defined in the Actions area of API.AI
    let intent = assistant.getIntent();
    switch (intent) {
      case WELCOME_INTENT:
        assistant.ask('Welcome! Say a number.');
        break;

      case NUMBER_INTENT:
        let number = assistant.getArgument(NUMBER_ARGUMENT);
        assistant.tell('You said ' + number);
        break;
    }
  }
  // you can add the function name instead of an action map
  assistant.handleRequest(responseHandler);
}


app.post('/google', function (req, res) {
  console.log(req.body);
  sillyNameMaker(req, res);
})


app.get('/', function (req, res) {
  res.send("Server is up and running.")
})


app.listen(3000, function () {
  console.log('Example app listening on port 3000!')
})

And the error I got:

TypeError: Cannot read property 'originalRequest' of undefined
    at new ApiAiAssistant (/Users/clementjoudet/Desktop/Dev/google-home/node_modules/actions-on-google/api-ai-assistant.js:67:19)
    at sillyNameMaker (/Users/clementjoudet/Desktop/Dev/google-home/main.js:8:21)

I'm trying to print req.body but it is undefined... Thanks in advance for your help.

Answer 1

Both you and the actions-on-google package are making an assumption about how you're using Express. By default, Express does not populate the req.body attribute (see the reference for req.body). Instead it relies on additional middleware such as body-parser to do so.

You should be able to add body parser to your project with

npm install body-parser

and then use it to parse the request body into JSON (which API.AI sends and actions-on-google uses) with some additional lines right after you define app to attach it to Express:

var bodyParser = require('body-parser');
app.use(bodyParser.json());