dereferenceDID Function

The dereferenceDID function is extended from the resolveDID function. It allows you to dereference a DID URL and retrieve the corresponding Verification Method, or Service.

Dereferencing a DID Document

The following examples demonstrate how to use the dereferenceDID function to retrieve a Verification Method or Service.

Dereference a DID Document Fragment

This example shows how to dereference a DID Document fragment. It can be used to retrieve a Verification Method, Verification Relationship, or Service. To dereference a DID Document fragment, the didUrl must contain a fragment. The fragment can be a verificationMethod, verificationRelationship, or service. For example, did:hedera:testnet:z6Mkhj…​#verificationMethod or did:hedera:testnet:z6Mkhj…​#service.

import { dereferenceDID } from '@swiss-digital-assets-institute/resolver';

const didUrl =
  'did:hedera:testnet:23g2MabDNq3KyB7oeH9yYZsJTRVeQ24DqX8o6scB98e3_0.0.5217215#did-root-key'; // Replace with the DID URL you want to dereference

async function main() {
  try {
    const verificationMethod = await dereferenceDID(didUrl);
    console.log(verificationMethod);
  } catch (error) {
    console.error('Error dereferencing DID:', error);
  }
}

main();

See a full running example in the source code.

Dereference a DID Document Service Endpoint

This example shows how to dereference a DID Document Service Endpoint. It can be used to retrieve a Service Endpoint. To dereference a DID Document Service Endpoint, the didUrl must contain a service parameter with additional relativeRef parameter. For example, did:hedera:testnet:z6Mkhj…​?service=github&relativeRef=hashgraph-did-sdk-js. As a result, the function will return the Service Endpoint of the github service. relativeRef is appended to the service endpoint as a path to the URL.

import { dereferenceDID } from '@swiss-digital-assets-institute/resolver';

const didUrl =
  'did:hedera:testnet:3f3zxTz93CXnqhW3bNxqeyk8Gfk7v2yR27DRgSTYvHog_0.0.5278919?service=github&relativeRef=hashgraph-did-sdk-js';

async function main() {
  try {
    const serviceEndpoint = await dereferenceDID(didUrl);
    console.log(serviceEndpoint);
  } catch (error) {
    console.error('Error dereferencing DID:', error);
  }
}

main();

See a full running example in the source code.

Different accept values

dereferenceDID supports different accept values in the same way as resolveDID. Currently, the only supported accept value is application/ld+json;profile="https://w3id.org/did-resolution", application/did+json, application/did+ld+json and application/did+cbor. Based on the accept value, the function will return the corresponding Verification Method, Verification Relationship, or Service Endpoint in the corresponding format. application/did+json and application/did+ld+json are the same format, but application/did+ld+json adds @context to the JSON-LD document. application/ld+json;profile="https://w3id.org/did-resolution" adds resolution and content metadata to the result. The application/did+cbor format is a binary format of the dereferenced fragment.

In example below, the accept value is application/ld+json;profile="https://w3id.org/did-resolution". As a result, the function will return the Verification Method in JSON-LD format with resolution and content metadata.

import { dereferenceDID } from "@hashgraph-did-js-sdk/resolver";

const didUrl = "did:hedera:testnet:z6Mkhj...#did-root-key"; // Replace with the DID URL you want to resolve

async function main() {
  try {
    const verificationMethodResolution = await dereferenceDID(
      didUrl,
      'application/ld+json;profile="https://w3id.org/did-resolution"'
    );
    console.log(verificationMethodResolution);
  } catch (error) {
    console.error("Error dereferencing DID:", error);
  }
}

main();

See a full running example in the source code.

Using TopicReader

The dereferenceDID function accepts an optional options parameter that allows you to specify a custom TopicReader implementation. This is useful if you need to read messages from the Hedera network using a custom topic reader.

Example below shows how to use a custom TopicReader implementation to read messages from the Hedera network using a default gRPC Hedera client.

import {
  dereferenceDID,
  TopicReaderHederaClient,
} from '@swiss-digital-assets-institute/resolver';

const didUrl =
  'did:hedera:testnet:23g2MabDNq3KyB7oeH9yYZsJTRVeQ24DqX8o6scB98e3_0.0.5217215#did-root-key';

async function main() {
  try {
    const topicReader = new TopicReaderHederaClient();
    const verificationMethod = await dereferenceDID(
      didUrl,
      'application/did+ld+json',
      {
        topicReader,
      },
    );
    console.log(verificationMethod);
  } catch (error) {
    console.error('Error dereferencing DID:', error);
  }
}

main();

See a full running example in the source code.

Using Verifier

The dereferenceDID function accepts an optional options parameter that allows you to specify a custom Verifier implementation. This is useful if you need to verify the DID Document signature using a custom verifier.

Example below shows how to use a custom Verifier implementation to verify the DID Document signature using a default internal verifier.

import { dereferenceDID } from '@swiss-digital-assets-institute/resolver';
import { Verifier } from '@swiss-digital-assets-institute/verifier-internal';

const didUrl =
  'did:hedera:testnet:23g2MabDNq3KyB7oeH9yYZsJTRVeQ24DqX8o6scB98e3_0.0.5217215#did-root-key';

async function main() {
  try {
    const verifier = Verifier.fromBase58(
      '23g2MabDNq3KyB7oeH9yYZsJTRVeQ24DqX8o6scB98e3',
    );
    const verificationMethod = await dereferenceDID(
      didUrl,
      'application/did+ld+json',
      {
        verifier,
      },
    );
    console.log(verificationMethod);
  } catch (error) {
    console.error('Error dereferencing DID:', error);
  }
}

main();

See a full running example in the source code.

References