@dsnp/did-resolver

Overview

This package implements a generic resolver for the dsnp DID method (that is, DIDs of the form did:dsnp:123456, where 123456 is a DSNP User Id in decimal format). This resolver must be used with one or more plugins for specific DSNP systems (see below).

Usage

This package follows the conventions described in the @digitalbazaar/did-io package and exposes a driver() function which returns an object with a get(options) method. Pass an array of DSNPResolver objects to the driver() method.

Usage for DSNP DID method only

import { CachedResolver } from "@digitalbazaar/did-io";
import didDsnp from "@dsnp/did-resolver";
import { FooResolver} from "dsnp-did-resolver-plugin-foo"; // See below for known plugins
// ... additional dsnp-did-resolver plugins if needed

const resolver = new CachedResolver();
resolver.use(didDsnp.driver([ new FooResolver() ]));

const myDid = "did:dsnp:123456";
const result = await resolver.get({ did: myDid });
console.log(JSON.stringify(result, null, 2));

Usage with other DID method resolvers

The CachedResolver can combine drivers for multiple DID methods as described in the did-io documentation. For example, if you also want to be able to resolve did:web:* DIDs, you can use the did-method-web driver alongside the DSNP driver.

import { CachedResolver } from "@digitalbazaar/did-io";
import didWeb from "@digitalbazaar/did-method-web";
import didDsnp from "@dsnp/did-resolver";
import { FooResolver} from "dsnp-did-resolver-plugin-foo";

const resolver = new CachedResolver();
resolver.use(didWeb.driver());
resolver.use(didDsnp.driver([ new FooResolver() ]));

// DID resolution proceeds as in previous example

Plugins

To resolve a DSNP User Id to a specific DSNP system, one or more instances of system-specific plugins are required. Array ordering defines the order in which this resolver will attempt to resolve a DSNP DID. It will return the result from the first plugin that returns a DID document.

Plugin development

Plugins should implement the DSNPResolver interface, which includes a resolve(bigint) function (see index.ts):

export interface DSNPResolver {
  resolve(dsnpUserId: bigint): Promise<object | null>;
}

The resolve() function should return null if the DSNP User Id cannot be resolved to a DID document for any reason. Plugins should avoid throwing errors except in dire circumstances, as errors from one plugin will cause any further plugins that have been registered to not be called.

DSNPResolver instances are passed to this library's driver() method as shown above.

Known plugins

System	Plugin package
Frequency	@dsnp/did-resolver-plugin-frequency

Please submit a pull request with any additional plugins.

Development

• npm install - install dependencies
• npm run build - compile
• npm run test - run unit tests
• npm run lint - run linter
• npm run format - reformat source files

Pull requests are welcomed with an accompanying github issue.