The receiving server can forward the message for us. For us to resolve the entire collection is a lot of work, especially since paginated followers collections only contain like 12 entries per page! Lots of people have over 300 followers.

A nil key gets handled by rsa.Sign* but we won't catch an empty pubkey url until some server finds an incorrect HTTP signature.

While here make apget print mail format by default, consistent with rest of system.

This lets it send activity which cannot be converted to mail such as Follow

This is actually valid according to the spec. This makes embedded Activities like Mentions neater, too.

Yet! Decoding shouldn't be too hard. But for now it's a TODO. At least error out so we don't send out crazy messages.

Clearer: set a body to read from, then change it when necessary. Fewer instructions! Also, mail clients don't really know what to do with text/markdown, so just use text/plain; that's what Gruber would want. Adds basic test case too

This stuff is generated programaticall now.

Moved to package sys, generated dynamically (and tested!).

This seems clear enough. In the regular email world we want direct recipients to be signalled in some way of our message. Recipients merely copied in (CC'd) don't need to be alerted but still get the message.

We've already looked up the entire actor so may as well return it, then let callers do what they want with the data.

This gets us a bit closer to seeing Mastodon's non-standard Mention activities.