Sending emails from remote server

[mavishak]

We succeeded to send email's running our script locally. But we had problems running them remotely:

This is the error message we got in the firebase log:

Error: Invalid login: 534-5.7.14 <https://accounts.google.com/signin/continue?sarp=1&scc=1&plt=AKgnsbt

Steps we took:

1. In index.js:

   const mailTransport = nodemailer.createTransport({
       service: 'gmail',
       auth: {
         user: SENDER_EMAIL,
         pass: SENDER_PASSWORD,
       },
     });

2. Allowing less secure apps into the SENDER_EMAIL account. https://myaccount.google.com/lesssecureapps

3. Allowing access to the SENDER_EMAIL account. Set SENDER_EMAIL to your default account. https://accounts.google.com/b/0/DisplayUnlockCaptcha

This link helped: Nodemailer with Gmail and NodeJS

Problem: It seems that access to SENDER_EMAIL account is not permanent. I didn't find what triggers it - It might be a timeout or that I mistakingly issued an access removal somehow.

• It sees changing our password to a stronger one helped see: https://stackoverflow.com/questions/1607828/how-to-use-gmail-as-a-free-smtp-server-and-overcome-captcha

Possible solution Nodemailer addresses this issue and recommends using a different provider. see:

• https://community.nodemailer.com/using-gmail/
• https://dev.to/chandrapantachhetri/sending-emails-securely-using-node-js-nodemailer-smtp-gmail-and-oauth2-g3a

One other thing It might be better to trigger a .onCreate event rather than .onWrite - in order to minimize the function calls and the threatening caust

[mavishak]

Problem The average time to send the emails out is 4 minutes (one lucky time it took 1 minute).

Problem solved We sent out a question in stackoverflow https://stackoverflow.com/questions/68146035/how-to-reduce-email-sending-time-using-nodemailer-and-firebase