part1

index.js

const functions = require("firebase-functions");
const nodemailer = require("nodemailer");


const fs = require("fs");
const path = require('path');

// The Firebase Admin SDK to access the Firebase Realtime Database.
const admin = require('firebase-admin');
admin.initializeApp()

const gmailEmail = functions.config().gmail.email;
const gmailPassword = functions.config().gmail.password;
const mailTransport = nodemailer.createTransport({
  service: "gmail",
  auth: {
    user: gmailEmail,
    pass: gmailPassword
  }
});

exports.mailFxn = functions.database
  .ref("/maker/{id}")
  .onCreate((snapshot, context) => {
    // Grab the current value of what was written to the Realtime Database.
    const makers = snapshot.val();
    console.log(makers.name);
    console.log(makers.email);

    const makerID = context.params.id;



    //firebase functions:config:set gmail.email=myemailID@gmail.com gmail.password=Mypassword
    //To set email and password

    //To view the set email and pass firebase functions:config:get

    sendEmail(makers, makerID);

    return null;
  });

function sendEmail(makers, makerID) {

  //http://www.google.com/accounts/DisplayUnlockCaptcha
  //https://myaccount.google.com/lesssecureapps
  //This link is important to enable accesses to google account

  var UNIQUE_NAME = makers.name;
  // var UNIQUE_ID = makerID;

  var UNIQUE_QR = `https://chart.googleapis.com/chart?chs=150x150&cht=qr&chl=${+makerID + 1000}`


  var filePath = path.join(__dirname, 'templates/makerEmail.html');

  fs.readFile(filePath, { encoding: 'utf-8' }, function (err, data) {
    data = data.toString();
    data = data.replace(/##UNIQUE_NAME/g, UNIQUE_NAME);
    // data = data.replace(/##UNIQUE_ID/g, UNIQUE_ID);
    data = data.replace(/##UNIQUE_QR/g, UNIQUE_QR);


    var mailOptions = {
      from: '"MakerEvent" <noreply@firebase.com>', // sender address 
      to: makers.email, // list of receivers 
      subject: 'Thank You For Registration', // Subject line 
      html: data // html body
    };



    try {
      mailTransport.sendMail(mailOptions);
    } catch (error) {
      console.error('There was an error while sending the email:', error);

      // errorEmails = functions.database.ref(`/emailError/${makerID}`).set({
      //   email: makers.email
      // })

    }


    return console.log(
      `Sending mail to ${makers.name} with stamp ${makers.stamp}`
    );
  });
}

//To deploy firebase deploy --only functions:mailFxn