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title: blue.microcosm.links.* #

hydrant implements a subset of microcosm constellation when it's built with the backlinks cargo feature (cargo build --features backlinks).

when enabled, hydrant indexes all AT URI and DID references found inside stored records into a reverse index. this lets you efficiently answer "what records link to this subject?".

blue.microcosm.links.getBacklinks #

return records that link to a given subject.

param	required	description
subject	yes	AT URI or DID to look up backlinks for.
source	no	filter by source collection, e.g. app.bsky.feed.like. also accepts collection:path form to further filter by field path, e.g. app.bsky.feed.like:subject.uri. the path is matched against the dotted field path within the record (. is prepended automatically).
did	no	filter links to those from specific users.
limit	no	max results to return (default 50, max 100).
cursor	no	opaque pagination cursor from a previous response.
reverse	no	if true, return results in reverse order (default false).

returns { backlinks: [{ uri, cid }], cursor? }.

results are ordered by source record rkey (ascending by default, descending when reverse=true). the cursor is stable across new insertions for TID rkey records.

blue.microcosm.links.getBacklinksCount #

return the number of records that link to a given subject.

param	required	description
subject	yes	AT URI or DID to count backlinks for.
source	no	filter by source collection (same format as getBacklinks).

returns { count }.