Minor Refactoring to NS record PR (#608)

* minor refactoring

* Fixed an ambiguous if condition

packages/dids/src/did-error.ts

@@ -61,6 +61,9 @@ export enum DidErrorCode {
  /** The DID resolver was unable to find the DID document resulting from the resolution request. */
  NotFound = 'notFound',
 
+ /** The DID resolver was unable to find the DID document in any authoritative gateway. */
+ NotFoundInAuthoritativeGateWay = 'notFoundInAuthoritativeGateWay',
+
  /**
  * The representation requested via the `accept` input metadata property is not supported by the
  * DID method and/or DID resolver implementation.

packages/dids/src/methods/did-dht.ts

@@ -808,13 +808,14 @@ export class DidDhtDocument {
  let bep44Message = await DidDhtDocument.pkarrGet({ gatewayUri, publicKeyBytes });
 
  // Verify the signature of the BEP44 message and parse the value to a DNS packet.
- let dnsPacket = await DidDhtUtils.parseBep44GetMessage({ bep44Message });
+ let dnsPacket: Packet | undefined = await DidDhtUtils.parseBep44GetMessage({ bep44Message });
 
  // Look at the NS records in the DNS packet to find the resolution gateway URIs.
- let resolutionGatewayUris = await DidDhtDocument.getAuthoritativeGatewayUris({ didUri, dnsPacket });
+ const resolutionGatewayUris = await DidDhtDocument.getAuthoritativeGatewayUris({ didUri, dnsPacket });
 
- // Only do a second retrieval if the authoritative resolution gateway URIs are different from the given gateway URI.
- if(!resolutionGatewayUris.includes(gatewayUri)) {
+ // Only do a second retrieval if authoritative resolution gateway URIs are specified and are different from the given gateway URI.
+ if(resolutionGatewayUris.length > 0 && !resolutionGatewayUris.includes(gatewayUri)) {
+ dnsPacket = undefined; // reset to `undefined` to use as a condition check for throwing an error
  const accumulatedErrors = [];
  for(const nsRecordGatewayUri of resolutionGatewayUris) {
  try {
@@ -823,17 +824,20 @@ export class DidDhtDocument {
  } catch (error: any) {
  accumulatedErrors.push(`Failed retrieval from ${nsRecordGatewayUri}: ${error}`);
 
- if(nsRecordGatewayUri == resolutionGatewayUris[resolutionGatewayUris.length - 1]) {
- throw new Error(`DID document not found for: ${didUri}. Errors: ${accumulatedErrors.join('; ')}`);
- }
-
  // If the retrieval failed, try the next resolution gateway.
  continue;
  }
 
  // If the retrieval was successful, break the loop.
  break;
  }
+
+ if(dnsPacket === undefined) {
+ throw new DidError(
+ DidErrorCode.NotFoundInAuthoritativeGateWay,
+ `DID document not found for: ${didUri} after looping through all authoritative gateways. Errors: ${accumulatedErrors.join('; ')}`
+ );
+ }
  }
 
  // Convert the DNS packet to a DID document and metadata.
@@ -1002,7 +1006,7 @@ export class DidDhtDocument {
  * @param {object} params - The parameters to use when extracting gateway URIs from the DNS packet.
  * @param {string} params.didUri - The DID URI corresponding to the DNS packet.
  * @param {Packet} params.dnsPacket - The DNS packet containing potential NS records for resolution gateways.
- * @returns {Promise<string[]>} Resolves to an array of gateway URIs if found, otherwise an empty array.
+ * @returns {Promise<string[]>} Resolves to an array of gateway URIs without trailing '.' if found, otherwise an empty array.
  */
  public static async getAuthoritativeGatewayUris({ didUri, dnsPacket }: {
  didUri: string;
@@ -1013,7 +1017,7 @@ export class DidDhtDocument {
  for (const answer of dnsPacket?.answers ?? []) {
  if (answer.type !== 'NS') continue;
 
- if(answer.name.endsWith(`.${DidDhtDocument.getUniqueDidSuffix(didUri)}.`)) {
+ if (answer.name.endsWith(`.${DidDhtDocument.getUniqueDidSuffix(didUri)}.`)) {
  const gatewayUri = answer.data.slice(0, -1); // Remove trailing dot
  authoritativeGatewayUris.push(gatewayUri);
  break;