did-resolver/lib/index.mjs

Resolve DID documents

// Copyright 2018 Consensys AG
/**
 * Represents the Verification Relationship between a DID subject and a Verification Method.
 *
 * @see {@link https://www.w3.org/TR/did-core/#verification-relationships}
 */
export const VerificationRelationship = {
    authentication: 'authentication',
    assertionMethod: 'assertionMethod',
    keyAgreement: 'keyAgreement',
    capabilityInvocation: 'capabilityInvocation',
    capabilityDelegation: 'capabilityDelegation',
};
export function inMemoryCache() {
    const cache = new Map();
    return async (parsed, resolve, options) => {
        if (options?.cache === false)
            return await resolve();
        const cached = cache.get(parsed.didUrl);
        if (cached !== undefined)
            return cached;
        const result = await resolve();
        if (result.didResolutionMetadata?.error !== 'notFound') {
            cache.set(parsed.didUrl, result);
        }
        return result;
    };
}
export function noCache(parsed, resolve) {
    return resolve();
}
// RFC 3986 ABNF components (referenced by DID Core v1.0 §3.2)
const HEXDIG = '[0-9a-fA-F]'; // allows both lowercase and uppercase
const PCT_ENCODED = `(?:%${HEXDIG}{2})`; // pct-encoded = "%" HEXDIG HEXDIG
// DID Core v1.0 §3.1
const ID_CHAR = `(?:[a-zA-Z0-9._-]|${PCT_ENCODED})`; // idchar
const METHOD = '[a-z0-9]+'; // method-name = 1*(%x61-7A / DIGIT)
const METHOD_ID = `(?:${ID_CHAR}*:)*${ID_CHAR}+`; // method-specific-id
// DID Core v1.0 §3.2 tail via RFC 3986 §3.3
const UNRESERVED = '[a-zA-Z0-9._~-]';
const SUB_DELIMS = "[!$&'()*+,;=]";
const PCHAR = `(?:${UNRESERVED}|${PCT_ENCODED}|${SUB_DELIMS}|[:@])`; // pchar
const PATH_ABEMPTY = `(?:/${PCHAR}*)*`; // path-abempty
const QUERY_CHARS = `(?:${PCHAR}|[/?])*`; // query
const FRAGMENT_CHARS = `(?:${PCHAR}|[/?])*`; // fragment
const DID_URL_MATCHER = new RegExp(`^did:(${METHOD}):(${METHOD_ID})(${PATH_ABEMPTY})(?:\\?(${QUERY_CHARS}))?(?:#(${FRAGMENT_CHARS}))?$`);
/**
 * Parses a DID URL strictly according to the DID Core v1.0 specification ABNF
 * (§3.1 DID Syntax, §3.2 DID URL Syntax). Unlike {@link parse}, this method
 * does not accept legacy DID parameters (`;key=value`) and enforces the
 * RFC 3986 character sets for path, query, and fragment components.
 *
 * @param didUrl - the DID URL string to be parsed
 * @returns a ParsedDID object, or null if the input does not conform to the spec
 */
export function parse(didUrl) {
    if (!didUrl)
        return null;
    const m = didUrl.match(DID_URL_MATCHER);
    if (!m)
        return null;
    const parsed = {
        did: `did:${m[1]}:${m[2]}`,
        method: m[1],
        id: m[2],
        didUrl,
    };
    // path-abempty always matches (possibly empty); only attach a real path.
    if (m[3])
        parsed.path = m[3];
    // query/fragment groups are `undefined` when absent, `''` when present but empty
    // (`did:x:y?` / `did:x:y#`), preserve the distinction.
    if (m[4] !== undefined)
        parsed.query = m[4];
    if (m[5] !== undefined)
        parsed.fragment = m[5];
    // params are intentionally omitted (matrix parameters not in DID Core v1.0 spec)
    return parsed;
}
const EMPTY_RESULT = {
    didResolutionMetadata: {},
    didDocument: null,
    didDocumentMetadata: {},
};
export function wrapLegacyResolver(resolve) {
    return async (did, parsed, resolver) => {
        try {
            const doc = await resolve(did, parsed, resolver);
            return {
                ...EMPTY_RESULT,
                didResolutionMetadata: { contentType: 'application/did+ld+json' },
                didDocument: doc,
            };
        }
        catch (e) {
            return {
                ...EMPTY_RESULT,
                didResolutionMetadata: {
                    error: 'notFound',
                    message: String(e), // This is not in spec, but may be helpful
                },
            };
        }
    };
}
/**
 * This implementation of {@link Resolvable} bundles together multiple implementations of {@link DIDResolver} and
 * presents a single function call to users.
 */
export class Resolver {
    registry;
    cache;
    constructor(registry = {}, options = {}) {
        this.registry = registry;
        this.cache = options.cache === true ? inMemoryCache() : options.cache === false ? noCache : options.cache || noCache;
        if (options.legacyResolvers) {
            Object.keys(options.legacyResolvers).map((methodName) => {
                if (!this.registry[methodName]) {
                    this.registry[methodName] = wrapLegacyResolver(options.legacyResolvers[methodName]);
                }
            });
        }
    }
    async resolve(didUrl, options = {}) {
        let parsed = parse(didUrl);
        if (parsed === null) {
            return {
                ...EMPTY_RESULT,
                didResolutionMetadata: { error: 'invalidDid' },
            };
        }
        const resolver = this.registry[parsed.method];
        if (!resolver) {
            return {
                ...EMPTY_RESULT,
                didResolutionMetadata: { error: 'unsupportedDidMethod' },
            };
        }
        // Use resolver's method-specific parser if available for additional validation
        if (resolver.parser) {
            const refined = resolver.parser(parsed);
            if (refined === null) {
                return {
                    ...EMPTY_RESULT,
                    didResolutionMetadata: { error: 'invalidDid' },
                };
            }
            parsed = refined;
        }
        return this.cache(parsed, () => resolver(parsed.did, parsed, this, options), options);
    }
}
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