{"id":32928,"date":"2021-06-23T16:14:39","date_gmt":"2021-06-23T20:14:39","guid":{"rendered":"https:\/\/mjtsai.com\/blog\/?p=32928"},"modified":"2021-07-07T11:58:25","modified_gmt":"2021-07-07T15:58:25","slug":"mail-app-extensions","status":"publish","type":"post","link":"https:\/\/mjtsai.com\/blog\/2021\/06\/23\/mail-app-extensions\/","title":{"rendered":"Mail App Extensions"},"content":{"rendered":"

Apple<\/a>:<\/p>\n

Meet MailKit: the best way to build amazing experiences on top of Mail. MailKit enables apps to easily and securely interact with the Mail app for macOS. We’ll deep dive into the MailKit API, and show you how to create extensions for composing messages, message actions, secure email, and content blocking.<\/p><\/blockquote>\n\n

Joe Rossignol<\/a>:<\/p>\n

\n

In the WWDC session, Apple indicated that older Mail app plug-ins will stop functioning in an unspecified future macOS release.<\/p>\n<\/blockquote>\n

Plug-ins still work in Monterey, and SpamSieve’s<\/a> is already in public beta<\/a>.<\/p>\n\n

Currently, MailKit’s<\/a> functionality is very limited<\/a>. Unless it’s expanded in a future version, I think a lot of plug-ins will not be able to make the transition to extensions, a loss to both their users and developers.<\/p>\n\n

For SpamSieve, I’m cautiously optimistic about extensions. In theory, the current Monterey API is sufficient to implement the core SpamSieve functionality, though implementing some of the more advanced features would require API changes (FB9176051, FB9176075, FB9176097). I say, “in theory,” because MailKit in the Monterey developer beta doesn’t work as designed\/documented. Extensions are supposed to be able to access the raw data<\/a> of the message, but currently they receive either incomplete data (FB9175977) or none at all (FB9176011).<\/p>\n\n

This takes me back to why I wrote a Mail plug-in in the first place<\/a>. I had resisted doing so because I didn’t want to rely on an unsupported private API. But the reason I ended up making a plug-in is that the official API (AppleScript rule actions) was buggy. The private API ended up being more reliable and faster. And I’ve even been able to patch Mail to fix some (FB7035263) but not all (FB7145734) of Mail’s AppleScript bugs and to tweak the interface to make it more readable.<\/p>\n\n

The private API has proven amazingly stable. I’ve always tried to make minimal hooks into Mail, and so the updates needed due to Mail code changes have been minor. The main hurdles have been unrelated to the API itself:<\/p>\n\n