sendgmail

README

sendgmail

sendgmail is a tool that uses Gmail in order to mimic sendmail for git send-email.

This tool has been modified from its original version. This new version, inspired by siketyan/sendgmail, uses the Gmail users.messages.send API instead of SMTP to send the email. This has the following advantages:

• The scope of the OAuth token can be limited to only sending emails. This avoids the potential danger created by generating a token with full Gmail permissions, which is necessary to send emails through Gmail using SMTP (when not using an app password, which grants even more permissions).

• Sent emails will always appear in the "Sent" folder in Gmail regardless of whether or not you CC yourself. In contrast, when a message is sent via SMTP, the message will not appear in the "Sent" folder unless you CC yourself.

Obtaining OAuth2 credentials for sendgmail

1. Go to the Google Cloud console.

   • Create a new project. You probably want to name it something like sendgmail in IAM & Admin > Settings and also in APIs & Services > OAuth consent screen.

2. Go to the Go quickstart page of the Gmail API documentation.

   • Click the Enable the API button. It will open another page in your browser. Follow the steps on that page to enable the Gmail API for the project that you created.

   • Follow the steps in the Authorize credentials for a desktop application section. However, set the application type to Web application (i.e. instead of Desktop app) and then add https://oauth2.dance/ as an authorised redirect URI. This is necessary for seeing the authorisation code on a page in your browser.

   • When you download the credentials as JSON, create the ${XDG_CONFIG_HOME:-${HOME}/.config}/sendgmail directory with file mode 0700 and then save the file to that directory as config.json with file mode 0600.

     For historical reasons, when the file named config.json does not exist under your config directory, sendgmail will try looking for a file named .sendgmail.json in your home directory.

3. Go back to APIs & Services > OAuth consent screen in the Google Cloud console.

   • Add USERNAME@gmail.com as a test user. This is necessary for using the project that you created.

   • Add https://www.googleapis.com/auth/gmail.send as a scope. This is necessary for sending emails via the Gmail API.

Installing sendgmail

Run the following command to build and install sendgmail to GOPATH/bin/sendgmail:

go install github.com/cyrozap/sendgmail@latest

Obtaining OAuth2 credentials for yourself

Run the following command to perform the OAuth2 dance:

GOPATH/bin/sendgmail -sender=USERNAME@gmail.com -setup

Using sendgmail

Add the following section to .gitconfig in your home directory:

[sendemail]
    smtpServer = GOPATH/bin/sendgmail
    smtpServerOption = -sender=USERNAME@gmail.com

Documentation

Overview

sendgmail is a tool that uses Gmail in order to mimic `sendmail` for `git send-email`.

USAGE:

$ /PATH/TO/sendgmail -sender=USERNAME@gmail.com -setup

$ git send-email --smtp-server=/PATH/TO/sendgmail --smtp-server-option=-sender=USERNAME@gmail.com ...