Upgrade from WebHook to Firebase function on dialogflow

May 22, 2019 min read

Webhooks have been on Dialogflow for a long time, but if you want to have more versatility controlling the responses, you need to use Fulfillment through a Firebase function.

How can we upgrade from webhooks to a Firebase function without losing our webhook functionality?

Given we had a webhook on a certain url myurl used by an intent, we could do the following.

First, we need to set the intent in the intentMap so we can create a new handler for this intent and put our webhook on it.

…

Then we need to set the dependencies, so we can make requests from the firebase function. We need this and that dependency to make this to work. It’s very important to notice that making requests to external urls from our Firebase function is not available unless we use a paid plan (Blaze, …), otherwise our webhook requests will be blocked in it won’t work, so we need to upgrade our plan to a paid one (how much would it cost per execution?)

After those two steps we need to create our handler, it will make the request to our external webhook and set the response in the agent, as we had before. if we have Context we need to separately set it too, but it’s not usually big deal.

[Set code and output of the webhook so we see what we have to parse for the agent.]

Debugging is easy for firebase functions, we could see the logs on Firebase, Dialogflow gives us a link below the firebase function for quick access.

// See https://github.com/dialogflow/dialogflow-fulfillment-nodejs
// for Dialogflow fulfillment library docs, samples, and to report issues
"use strict";

const functions = require("firebase-functions");
const { WebhookClient } = require("dialogflow-fulfillment");
const { Card, Suggestion } = require("dialogflow-fulfillment");
const requestClient = require("request-promise-native");

const URL = "https://example.com/hook?token=token";

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 gameFunctionHandler(agent) {
      var options = {
        method: "POST",
        uri: URL,
        body: request.body,
        json: true // Automatically stringifies the body to JSON
      };

      return requestClient(options)
        .then(function(parsedBody) {
          agent.add(parsedBody.fulfillmentText);
          const contexts = parsedBody.outputContexts;
          let context;

          for (var i in contexts) {
            context = contexts[i].name.split("/");
            const context_name = context[context.length - 1];
            agent.setContext({
              name: context_name,
              lifespan: contexts[i].lifespanCount,
              parameters: contexts[i].parameters
            });
          }

          return Promise.resolve(agent);
        })
        .catch(function(err) {
          console.log(err);
        });
    }

    // Run the proper function handler based on the matched Dialogflow intent name
    let intentMap = new Map();
    intentMap.set("Default Welcome Intent", welcome);
    intentMap.set("Default Fallback Intent", fallback);
    intentMap.set("game", gameFunctionHandler);
    intentMap.set("game-fallback", gameFunctionHandler);
    agent.handleRequest(intentMap);
  }
);

package.json

{
  "name": "dialogflowFirebaseFulfillment",
  "description": "This is the default fulfillment for a Dialogflow agents using Cloud Functions for Firebase",
  "version": "0.0.1",
  "private": true,
  "license": "Apache Version 2.0",
  "author": "Google Inc.",
  "engines": {
    "node": "8"
  },
  "scripts": {
    "start": "firebase serve --only functions:dialogflowFirebaseFulfillment",
    "deploy": "firebase deploy --only functions:dialogflowFirebaseFulfillment"
  },
  "dependencies": {
    "actions-on-google": "^2.2.0",
    "firebase-admin": "^5.13.1",
    "firebase-functions": "^2.0.2",
    "dialogflow": "^0.6.0",
    "dialogflow-fulfillment": "^0.5.0",
    "request-promise-native": "^1.0.5",
    "request": "^2.88"
  }
}