@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 should be used with one or more plugins for specific DSNP systems (see below).

Usage

This package follows the conventions described in the did-resolver package and exposes a getResolver() function which returns a mapping from the dsnp DID method to a resolver function. Pass an array of plugins to the getResolver() method.

Usage for DSNP DID method only

import { Resolver } from "did-resolver";
import dsnpResolver 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 Resolver(dsnpResolver.getResolver(
  [ new FooResolver() ]
));
const myDid = "did:dsnp:123456";
const result = await resolver.resolve(myDid);
console.log(JSON.stringify(result, null, 2));

Usage with other DID method resolvers

The Resolver constructor can combine resolvers for multiple DID methods as described in the did-resolver documentation. For example, if you also want to be able to resolve did:ethr:* DIDs, you would import and include the ethr resolver and pass its destructured resolver alongside the DSNP one to the constructor as follows:

import ethrResolver from "ethr-did-resolver";
// ... additional did-resolver packages; 

const resolver = new Resolver({
  ...dsnpResolver.getResolver([plugin]),
  ...ethrResolver.getResolver()
});
// usage is same 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<DIDDocument | null>;
}

The DIDDocument type is defined in the did-resolver package.

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 the getResolver() function.

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.