@atcute/repo

read AT Protocol repository exports.

npm install @atcute/repo

AT Protocol stores user data in repositories - Merkle tree structures containing records organized by collection. this package reads repository CAR exports (from com.atproto.sync.getRepo or account exports) and iterates over the records.

usage

streaming usage

[!NOTE]
PDS implementations, including the reference PDS, may not emit blocks in the efficient order specified by Sync v1.1. the streaming reader compensates by buffering internally, so memory usage may be higher than expected.

streaming may still be useful when responsiveness matters, such as web apps that want to display records as they arrive rather than waiting for the entire CAR to load.

this library intends to enforce efficient block ordering once Sync v1.1 is finalized.

import { fromStream } from '@atcute/repo';

const stream = new ReadableStream({
	/* ... */
});

await using repo = fromStream(stream);

for await (const entry of repo) {
	entry;
	// ^? RepoEntry { collection: 'app.bsky.feed.post', rkey: '3lprcc55bb222', ... }
}

repo.missingBlocks;
//   ^? []

streaming usage (for runtimes without await using yet)

const repo = fromStream(stream);

try {
	for await (const entry of repo) {
		entry;
		// ^? RepoEntry
	}
} finally {
	await repo.dispose();
}

sync usage

const buffer = Uint8Array.from([
	/* ... */
]);

const repo = fromUint8Array(buffer);

for (const entry of repo) {
	entry;
	// ^? RepoEntry { collection: 'app.bsky.feed.post', rkey: '3lprcc55bb222', ... }
}

repo.missingBlocks;
//   ^? []

verifying records

verify a record's inclusion in a repository with optional signature verification:

import { verifyRecord } from '@atcute/repo';

const { cid, record } = await verifyRecord({
	collection: 'app.bsky.feed.post',
	rkey: '3lprcc55bb222',
	carBytes: carBytes,
	// optional: verify commit signature
	publicKey: key,
	// optional: verify DID matches
	did: 'did:plc:...',
});

transform streams

for piping repository data through a transform:

import { repoEntryTransform } from '@atcute/repo';

const { readable, writable } = repoEntryTransform();

// pipe CAR data in, get RepoEntry objects out
response.body.pipeTo(writable);

for await (const entry of readable) {
	console.log(entry.collection, entry.rkey);
}