Example Dialogflow implementation, branching on parameters and returning text strings

chatserver-node.js

require('dotenv').config() //load environemnt vars

const projectId = process.env.GCLOUD_PROJECT; //your project name
const uuidv1 = require('uuid/v1');
const sessionId = uuidv1();
const languageCode = 'en-US';

const server = require('http').createServer((request, response) => {
    response.writeHead(200, {"Content-Type": "text/html"});
    response.write(`Chat Server Running`);
    response.end();
});

const io = require('socket.io')(server);
io.set('origins', '*:*');
const structjson = require('./structjson');
const dialogflow = require('dialogflow');

const sessionClient = new dialogflow.SessionsClient();
const sessionPath = sessionClient.sessionPath(projectId, sessionId);

function detectIntent(request, cb){
    // Send request and log result
    sessionClient.detectIntent(request)
    .then(responses => {
        var result = responses[0].queryResult;

        if(result){
 
            var dialogs = result.fulfillmentMessages;
            for (var i = 0, len = dialogs.length; i < len; i++) {
                var messageType = dialogs[i].message; //text || payload
                var answer = dialogs[i]["text"].text;
            }

            // set the action in Dialogflow to Mortgage
            if(result.action && result.action == 'mortgage') {
                
                // imagine the string literals are retrieved from a database

                var dataMap_en = new Map();
                    dataMap_en.set('H001', "Buying a house.");
                    dataMap_en.set('H002', "Buying a villa.");
                    dataMap_en.set('H003', "Buying a apartment.");
                    dataMap_en.set('H004', "Buying a bungalow. Is this your second mortgage?");
                    dataMap_en.set('Fallback', "That's not an option. You can choose between a house, villa, apartment or bungalow.");
                var dataMap_nl = new Map();
                    dataMap_nl.set('H001', "Een huis kopen.");
                    dataMap_nl.set('H002', "Een villa kopen.");
                    dataMap_nl.set('H003', "Een appartement kopen.");
                    dataMap_nl.set('H004', "Een recreatie woning kopen. Is dit uw tweede hypotheek?");
                    dataMap_nl.set('Fallback', "Dit is helaas geen optie. U kunt een huis, villa, appartement of bungalow kiezen.");
                var dataMap = {};
                    dataMap['en-us'] = dataMap_en;
                    dataMap['nl-nl'] = dataMap_nl;
                
                // @housing_type entity in Dialogflow
                var param = p['housing_type'];

                // language code from Dialogflow
                var lang = result.languageCode;
    
                switch( param ){
                    case 'H004':
                      answer = dataMap[lang].get('H004');

                      // FOLLOW UP QUESTIONS
                      // Just start a new intent with training phrases
                      // Or fire an event to move to the next intent
                      
                        break;
                    default:
                        if(param) {
                            answer = dataMap[lang].get(param);
                        } else {
                            answer = dataMap[lang].get('Fallback');
                        }
                }

                console.log(answer);
                
            }

            if(answer){
                //console.log(result.intent.intentDetectionConfidence);
                cb(answer, result.intent.intentDetectionConfidence, "ChatBot");
                console.log(answer[0]);
            }
        }
    })
    .catch(err => {
        console.error('ERROR:', err);
        io.emit('systemerror', {
            username: "ChatBot",
            message: err
        });
    });
}

io.on('connection', function(client){
    
    // when the client emits 'msg', this listens and executes
    client.on('msg', function(data){

        // The text query request.
        const request = {
            session: sessionPath,
            queryInput: {
            text: {
                text: data,
                languageCode: languageCode,
            },
            },
        };

        detectIntent(request, function(botAnswer, confidence, botName){

            // we tell the client to execute 'agentmsg'
            io.emit('agentmsg', {
                username: botName,
                message: botAnswer,
                confidence: confidence,
                session: client.id
            });
        });
    });

    client.on('disconnect', function(){
        console.log("Close Connection");
    });
});
server.listen(3000); //TODO