@dsnp/did-resolver-frequency

Overview

This package contains a resolver for the @dsnp/did-resolver library which enables resolution of did:dsnp:* DIDs on the Frequency blockchain.

Installation

npm install @dsnp/did-resolver-frequency

Usage

The resolver object can be constructed with Frequency connection information in one of two ways.

• Construct with provider URI:

import { FrequencyResolver } from "@dsnp/did-resolver-frequency";

const frequencyResolver = new FrequencyResolver({
  providerUri: "ws://127.0.0.1:9944",
});

If constructed this way, you must call disconnect() to explicitly release the connection; the process will not exit if this is not done.

or,

• Construct with preconfigured Promise<ApiPromise> object from @polkadot/api:

import { FrequencyResolver } from "@dsnp/did-resolver-frequency";

const frequencyResolver = new FrequencyResolver({
  apiPromise: myApiPromise, // from ApiPromise.create(...)
});

Summary of options:

Configuration option	Description
providerUri	Provider URI for Frequency RPC node (optional; alternative to apiPromise
apiPromise	A Promise<ApiPromise> (optional; alternative to providerUri

See .env.example for example configuration.

Here's a full usage example with the did-io DID resolver framework:

import { CachedResolver } from "@digitalbazaar/did-io";
import didDsnp from "@dsnp/did-resolver"; 
import { FrequencyResolver } from "@dsnp/did-resolver-frequency";

const frequencyResolver = new FrequencyResolver({
  providerUri: "wss://1.rpc.frequency.xyz",
});

const resolver = new CachedResolver();
resolver.use(didDsnp.driver([ frequencyResolver ]));
const did = "did:dsnp:123456";
const result = await resolver.get({ did });
console.log(JSON.stringify(result, null, 2));

await frequencyResolver.disconnect();

/* Example output:
{
  "@context": [
    "https://www.w3.org/ns/did/v1"
  ],
  "id": "did:dsnp:1",
  "assertionMethod": [
    {
      "@context": "https://w3id.org/security/multikey/v1",
      "id": "did:dsnp:1#z6MktEsFq4c5qFZkj3wq5FZDurXLpG1s9gD7oWDZoS8S5F27",
      "type": "Multikey",
      "controller": "did:dsnp:1",
      "publicKeyMultibase": "z6MktEsFq4c5qFZkj3wq5FZDurXLpG1s9gD7oWDZoS8S5F27"
    }
  ],
  "keyAgreement": []
}
*/

CLI

The example above is provided as a command line script.

cp .env.example .env
# uncomment the desired node endpoint
npm run resolve -- 13972

Features

Currently this resolver implements the minimal functionality required to support lookup of public keys by DSNP applications.

• DSNP control keys are listed in the authentication array.
• DSNP keyAgreementPublicKeys are listed in the keyAgreement array.
• DSNP assertionMethodPublicKeys are listed in the assertionMethod array.
• A user's Frequency handle, if one exists, is noted in the alsoKnownAs array with a did:frqcy:handle: prefix.

All public keys are encoded using the Multikey type. The id consists of the DSNP DID and a URL fragment that is the same as the publicKeyMultibase value, which is a multicodec value in base58btc encoding. The decoded value for ed25519-pub keys will be 34 bytes, including the two-byte multicodec identifier.