gmail_xoauth2

How to use XOAUTH2 authentication in the mailer lib (version ^3.0.0)

This example uses the googleapis_auth library.

OAuth2 google credentials are explained here

Get an app id

Go to the API & Services dashboard and "create credentials" with type other.

You will get an app-id and an app-secret.

It should also be possible to create a service account. However AFAIK only google apps accounts are allowed to do that. For more information see googleapis_auth → Autonomous Application / Service Account

You want to send mails with your account.

This is acceptable if you are using mailer in a server (command line) app.

Do not use your account in flutter apps. It is possible to extract credentials from apps and an attacker would be able to send spam using your account.

I unfortunately don't know how to find out which account has been used when asking for permissions. You therefore have to specify the username (--username) manually. They obviously have to match.

First retrieve the credentials using obtain_credentials.dart:
dart bin/obtain_credentials.dart --username '[email protected]' --file '/tmp/secrets.json --id 'YOUR_ID.apps.googleusercontent.com' --secret 'YOUR_SECRET'

You can then send mails using: dart bin/send_mail.dart --file '/tmp/secrets.json --to '[email protected]'

Again don't store your credentials in any mobile app!

Send mail in flutter apps.

You will need to ask the user.

Write your own prompt function (obtain_credentials.dart) which displays the homepage to the user.

Then ask the user for its email-address and store the credentials somewhere.