Editing the context variables in Watson Assistant for a specific dialogue node using Node js

Question

I have a code that links Watson conversation to facebook messenger. Now, I want to implement the following conversation -
User: I need a vehicle
Bot: Tell the location where the vehicle is needed
User: Santa Monica Pier
Bot: ****identifies the location as a context variable ($location) from Watson Assistant*
*Finds out the ETA from node app and sends it to Watson Assistant as a context variable ($ETA) ****
Bot: Your vehicle will arrive in $ETA minutes.

My code is -

var express = require('express');
var request = require('request');
var bodyParser = require('body-parser');
var watson = require('watson-developer-cloud');
var app = express();
var contexid = "";

app.use(bodyParser.urlencoded({ extended: false }))
app.use(bodyParser.json())

var conversation_id = "";
var w_conversation = watson.conversation({
    url: 'https://gateway.watsonplatform.net/conversation/api',
    username: process.env.CONVERSATION_USERNAME || 'username',
    password: process.env.CONVERSATION_PASSWORD || 'pass',
    version: 'v1',
    version_date: '2016-07-11'
});
var workspace = process.env.WORKSPACE_ID || 'id';

app.get('/webhook/', function (req, res) {
    if (req.query['hub.verify_token'] === 'fb_token') {
        res.send(req.query['hub.challenge']);
    }
    res.send('Error : no token.');
});

app.post('/webhook/', function (req, res) {
    var text = null;

    messaging_events = req.body.entry[0].messaging;
    for (i = 0; i < messaging_events.length; i++) { 
        event = req.body.entry[0].messaging[i];
        sender = event.sender.id;

        if (event.message && event.message.text) {
            text = event.message.text;
        }else if (event.postback && !text) {
            text = event.postback.payload;
        }else{
            break;
        }

        var params = {
            input: text,
            // context: {"conversation_id": conversation_id}
            context:contexid
        }

        var payload = {
            workspace_id: "id"
        };

        if (params) {
            if (params.input) {
                params.input = params.input.replace("\n","");
                payload.input = { "text": params.input };
            }
            if (params.context) {
                payload.context = params.context;
            }
        }
        callWatson(payload, sender);
    }
    res.sendStatus(200);
});

function callWatson(payload, sender) {
    w_conversation.message(payload, function (err, convResults) {
         console.log(convResults);
        contexid = convResults.context;

        if (err) {
            return responseToRequest.send("Erro.");
        }

        if(convResults.context != null)
           conversation_id = convResults.context.conversation_id;
        if(convResults != null && convResults.output != null){
            var i = 0;
            while(i < convResults.output.text.length){
                sendMessage(sender, convResults.output.text[i++]);
            }
        }

    });
}

function sendMessage(sender, text_) {
    text_ = text_.substring(0, 319);
    messageData = { text: text_ };

    request({
        url: 'https://graph.facebook.com/v2.6/me/messages',
        qs: { access_token: token },
        method: 'POST',
        json: {
            recipient: { id: sender },
            message: messageData,
        }
    }, function (error, response, body) {
        if (error) {
            console.log('Error sending message: ', error);
        } else if (response.body.error) {
            console.log('Error: ', response.body.error);
        }
    });
};

var token = "token";
var host = (process.env.VCAP_APP_HOST || 'localhost');
var port = (process.env.VCAP_APP_PORT || 3000);
app.listen(port, host);

How do I identify the location as a context variable ($location) from Watson Assistant and send ETA from node app to Watson Assistant as a context variable? I was thinking of using action to make a programmatic call in my Watson dialogue node to do it but was unable to implement it.

Answer 1

convResults will contain the full context object, including the context variables that your dialog has set.