app.js

const dialogflow = require('@google-cloud/dialogflow');
const uuid = require('uuid');
const express = require('express');
const bodyParser = require('body-parser');
const app = express();
const port = 5000;

const sessionId = uuid.v4();



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


//code for cors - 

app.use(function (req, res, next) {

    res.setHeader('Access-Control-Allow-Origin', '*');
    res.setHeader('Access-Control-Allow-Methods', 'GET, POST, OPTIONS, PUT, PATCH, DELETE');
    res.setHeader('Access-Control-Allow-Headers', 'X-Requested-With,content-type');
    res.setHeader('Access-Control-Allow-Credentials', true);
  
    // Pass to next layer of middleware
    next();
  });



app.post('/send-msg',(req,res)=>{
     runSample(req.body.MSG).then(data=>{
      res.send({Reply:data});
     })
})


/**
 * Send a query to the dialogflow agent, and return the query result.
 * @param {string} projectId The project to be used
 */
async function runSample(msg,projectId = 'student-support-system-vpdx') {
  // A unique identifier for the given session
  // const sessionId = uuid.v4();

  // Create a new session
  const sessionClient = new dialogflow.SessionsClient({
    keyFilename:"D:/Student_Support_System/student-support.json"
  });
  const sessionPath = sessionClient.projectAgentSessionPath(
    projectId,
    sessionId
  );

  // The text query request.
  const request = {
    session: sessionPath,
    queryInput: {
      text: {
        // The query to send to the dialogflow agent
        text: msg,
        // The language used by the client (en-US)
        languageCode: 'en-US',
      },
    },
  };

  // Send request and log result
  const responses = await sessionClient.detectIntent(request);
  console.log('Detected intent');
  const result = responses[0].queryResult;
  console.log(`  Query: ${result.queryText}`);
  console.log(`  Response: ${result.fulfillmentText}`);
  if (result.intent) {
    console.log(`  Intent: ${result.intent.displayName}`);
  } else {
    console.log('  No intent matched.');
  }
  return result.fulfillmentText;
}

app.listen(port,()=>{
  console.log("Listening on port",port);
})