email-oauth2-proxy | SMTP proxy that transparently adds OAuth

After downloading the contents of this repository, start by editing the file emailproxy.config to add configuration details for each server and account you want to use with the proxy. Documentation and example account configurations are provided for Office 365 and Gmail, but you will need to register a new Microsoft identity or Google API desktop app client (or use your existing desktop app's client ID and secret). Make sure your client is set up to use an OAuth scope that will give it permission to access IMAP/SMTP – see the sample configuration file for examples. You can remove details from the sample configuration file for services you don't use, or add additional ones for any other OAuth 2.0 IMAP/SMTP servers you would like to use with the proxy (note: services other than Office 365 and Gmail have not been tested, but should work – please open an issue if not). Multiple accounts with the same provider can share the same server, and the correct server to use with an account is identified using the port number you configure in your client, as explained below. Account names (i.e., email addresses) must be unique – only one entry per account is permitted in the configuration file. Once the proxy is running, you can view or update the current configuration from its menu (via the Servers and accounts option). Next, from a terminal, install the script's requirements: python3 -m pip install -r requirements.txt, and start the proxy: python3 emailproxy.py – a menu bar/taskbar icon should appear. If instead of the icon you see an error in the terminal, it is likely that your system is missing dependencies for the pywebview or pystray packages. See the Dependencies and setup section below to resolve this. Once any missing dependencies have been installed, starting the proxy should create a menu bar icon. Finally, open your email client and configure your account's server details to match the ones you set in the proxy's configuration file. For example, using the sample Office 365 details, this would be localhost on port 1993 for IMAP and localhost on port 1587 for SMTP. The local connection in your email client should be configured as unencrypted to allow the proxy to operate, but the connection between the proxy and your email server is secured (implicit SSL/TLS for IMAP; implicit or explicit (STARTTLS) SSL/TLS for SMTP). The first time your email client makes a request you should see a notification from the proxy about authorising your account. (Note that the notification is not itself clickable, but pull requests to improve this are very welcome). Click the proxy's menu bar icon, select your account name in the Authorise account submenu, and then log in via the popup browser window that appears. The window will close itself once the process is complete. After successful authentication and authorisation you should have IMAP/SMTP access to your account as normal. Make sure you keep the proxy running at all times to allow it to authorise your email client's background activity – see the next section for instructions about how to do this. No further proxy interaction should be required unless your account needs authorising again, but it will notify you if this is the case.
On macOS the setup and installation instructions above should automatically install all required dependencies. Any error messages you may encounter (for example, with your pip version and cryptograpy, or pillow and imagingft dependencies) normally point to clear explanations of how to resolve these issues. Please open an issue if you encounter any other problems here. When first launching on Linux you may encounter errors similar to Namespace […] not available. This is caused by missing dependencies for pystray and pywebview, which are used to display the menu bar icon and login windows. See the pywebview dependencies page and issue 1 in this repository for a summary and suggestions about how to resolve this. A similar issue may occur on Windows with the pythonnet package, which is required for pywebview. If you are unable to resolve this by following the pythonnet installation instructions, you may find that installing a prebuilt wheel helps fix the issue.