@atcute/lexicon-resolver

resolve lexicon schemas from the AT Protocol network.

npm install @atcute/lexicon-resolver

usage

resolving lexicon authority

find which DID is authoritative for an NSID via DNS TXT records:

import { DohJsonLexiconAuthorityResolver } from '@atcute/lexicon-resolver';

const authorityResolver = new DohJsonLexiconAuthorityResolver({
    dohUrl: 'https://mozilla.cloudflare-dns.com/dns-query',
});

const authority = await authorityResolver.resolve('app.bsky.feed.post');
// -> 'did:plc:4v4y5r3lwsbtmsxhile2ljac'

fetching lexicon schemas

retrieve the lexicon document from an authority's PDS:

import {
    CompositeDidDocumentResolver,
    PlcDidDocumentResolver,
    WebDidDocumentResolver,
} from '@atcute/identity-resolver';
import { LexiconSchemaResolver } from '@atcute/lexicon-resolver';

const schemaResolver = new LexiconSchemaResolver({
    didDocumentResolver: new CompositeDidDocumentResolver({
        methods: {
            plc: new PlcDidDocumentResolver(),
            web: new WebDidDocumentResolver(),
        },
    }),
});

const resolved = await schemaResolver.resolve(authority, 'app.bsky.feed.post');
// -> { uri: string, cid: string, rawSchema: unknown, schema: LexiconDoc }

error handling

import {
    AuthorityNotFoundError,
    InvalidResolvedAuthorityError,
    LexiconAuthorityResolutionError,
    InvalidLexiconSchemaError,
    LexiconResolutionError,
} from '@atcute/lexicon-resolver';

try {
    await authorityResolver.resolve(nsid);
} catch (err) {
    if (err instanceof LexiconAuthorityResolutionError) {
        // authority resolution failed
    }
}

try {
    await schemaResolver.resolve(authority, nsid);
} catch (err) {
    if (err instanceof LexiconResolutionError) {
        // schema resolution failed
    }
}