[Node.js/cloud functions] Send mail from yahoo mail account with nodemailer

Overview

In the smartphone app, I implemented a function that notifies me by e-mail when a certain type of data is posted using firebase's cloud functions. There were some stumbling points along the way, so I'll write them down.

Detail

Overview

Create a function to send an email with cloud functions. The trigger for executing the function is when the document is created in the "\ data" collection of firestore. The sender of the email is the yahoo Japan email account, and the destination of the email is the gmail account.

Implementation

I implemented it as follows.

const functions=require("firebase-functions");
const admin=require("firebase-admin");
admin.initializeApp(functions.config().firebase);

const nodemailer=require('nodemailer');
const smtpTransport=require("nodemailer-smtp-transport");

const email=functions.config().mailfrom.address;
const password=functions.config().mailfrom.password;

let transporter=nodemailer.createTransport(smtpTransport({
    host: 'smtp.mail.yahoo.co.jp',
    port: 465,
    secure: true,
    auth: {
        user: email,
        pass: password
    }
}));

exports.sendOpinion=functions.firestore.document('data/{id}')
.onCreate((snapshot,context)=>{
    const to=functions.config().mailto.address;
    const data=snapshot.data();
    const title=data.title;
    const detail=data.detail;
    const msg="タイトル： "+title+"\n詳細： "+detail;
    const mailOptions={
        from: email,
        to: to,
        subject: 'データが投稿されました',
        text: msg
    };
    
    return transporter.sendMail(mailOptions, (erro,info)=>{
        if(erro){
            return res.send(erro.toString());
        }
        return res.send('Sended');
    });
        
});

The configuration of firestore is as follows.

data

|- title

|- detail

In addition, the sender, destination email address, and password are set in the environment variables of firebase. (Don't write directly in the code)

Error and Solution

Too many bad auth attempts.

→ use nodemailer-smtp-transport

554 Cannot send message due to possible spam

→ There was no text.

Greeting never received

→ secure: true

Lastly

You can now notify by email when the data is posted.

In my case, I use the above when an opinion about the app is posted, but I think that there are other ways to use it, such as when a user is added.