Syntax	Description	Examples
`"` keyword `"`	Finds the string within quotes, including spaces. Case-insensitive. (Escape quotes inside with `\"`)	`"Hackers' Pub"`
`from:` handle	Finds content written by the specified user.	`from:hongminhee` `from:hongminhee@hollo.social`
`lang:` ISO 639-1	Finds content written in the specified language.	`lang:en`
`#` tag	Finds content with the specified tag. Case-insensitive.	`#HackersPub`
condition condition	Finds content that satisfies both conditions on either side of the space (logical AND).	`"Hackers' Pub" lang:en`
condition `OR` condition	Finds content that satisfies at least one of the conditions on either side of the OR operator (logical OR).	`#HackersPub OR "Hackers' Pub" lang:en`
`(` condition `)`	Combines the operators within the parentheses first.	`(#HackersPub OR "Hackers' Pub" OR "Hackers Pub") lang:en`

Announce and Undo(Announce) in Mastodon

julian @julian@activitypub.space

NodeBB federates out the <code>Announce</code> activity in two ways. <ol> <li>The "plain object" way, which is an <code>Announce</code> activity wrapping an object (either a uri or the full object itself.)</li> <li>The "1b12" way, which is an <code>Announce</code> activity wrapping another activity (e.g. <code>Create</code>)</li> </ol> Up until now I haven't needed to handle the reverse (which in AP-speak is the "undo" of an activity), but since NodeBB sends <code>Announce</code> when moving a topic in to category, it now makes sense to <code>Undo(Announce)</code> when moving a topic out of a category.

If you have a fediverse account, you can quote this note from your own instance. Search https://activitypub.space/post/648 on your instance and quote it. (Note that quoting is not supported in Mastodon.)