did:dht resolution

[amika-sq]

(Adding reviewers that I know are semi familiar with did:dht resolution. Feel free to add anyone else if I might have missed anyone!)

This PR adds did:dht resolution.

How-To

did:dht resolution can be done either by interacting directly with the DIDDHT.Resolver struct, or by resolving using the generic DIDResolver, which can resolve any supported DID Method

Resolving directly with DIDDHT.Resolver

Resolution can be accomplished via the DIDDHT.Resolver struct:

1. With the default options:

let resolver = DIDDHT.Resolver()
await resolver.resolve(didURI: "did:dht:1234")

2. With a custom gateway:

let resolver = DIDDHT.Resolver(
    options: .init(gatewayURI: "https://my-custom-gateway.org")
)
await resolver.resolve(didURI: "did:dht:1234")

Resolving with DIDResolver

Resolution can also be accomplished with the DIDResolver simply by calling it with a DID URI:

await DIDResolver.resolve(didURI: "did:dht:1234")

By default, DIDResolver uses the default options to resolve the DID. If you want to customize the resolution process, create a new DIDDHT.Resolver, define your desired custom options, and register it.

Note

This will cause all did:dht resolutions to use the custom resolution options

let resolver = DIDDHT.Resolver(
    options: .init(gatewayURI: "https://my-custom-gateway.org")
)
DIDResolver.register(resolver: resolver)
await DIDResolver.resolve(didURI: "did:dht:1234")

[decentralgabe]

awesome work. after the test vectors pass this should be good to go

[decentralgabe]

if these tests rely on DIDs being present on this node it will work for some time...then break when we move to our prod node.

separately I believe it's crucial to implement tests for the two vectors the spec currently has https://did-dht.com/#test-vectors

[amika-sq]

I copied these tests from the web5-js repo here.

In terms of the test-vectors defined in the spec, I'm a little confused as to what exactly they are representing. It looks like they are not resolution vectors, but instead are importing keys, and verifying a particular DIDDocument is constructed from them. Creation/Importing will be coming in a later PR, and should be able to handle those. Do let me know if I'm misunderstanding those though!

[decentralgabe]

they are not exactly resolution vectors, you are correct. they make sure you can construct a consistent document and packet given a set of inputs.

I mention it now because you have implemented fromDNSPacket which could exercise the listed vectors DNS packets and compare them to the resulting DID document.

[amika-sq]

Added these vectors in the following commit: 93351ac

These vectors are kind of a deviation from the existing resolve vectors in the web5-spec here, so I decided to just implement them directly in Swift for the time being. Eventually, I think these should work their way into the web5-spec repo though, so that we ensure they pass across all SDKs. Just a matter of aligning on input/output formats!

[decentralgabe]

thank you @amika-sq I noted a comment here and will make sure to get these updated.

[decentralgabe]

awesome work