NFT DID Resolver

NFT is a DID method that uses the Ceramic network to resolve DID documents for NFTs

See CIP-94

Getting started

This implementation is still a prototype. Contributions are welcome!

To use a package, you would need to provide three subgraph endpoints for every network you are going to use: one for blocks, one for ERC721 tokens, another for ERC1155 tokens. You would also need to provide a skew that is a time (in milliseconds) within which a latest block is considered valid. Usually it is a typical block time.

Installation

$ npm install nft-did-resolver

Usage

import { getResolver } from 'nft-did-resolver'
import type { NftResolverConfig } from 'nft-did-resolver'
import { Resolver } from 'did-resolver'
import Ceramic from '@ceramicnetwork/http-client'

const ceramic = new Ceramic() // connects to localhost:7007 by default

const config: NftResolverConfig = {
  ceramic,
  chains: {
    'eip155:1': {
      blocks: 'https://api.thegraph.com/subgraphs/name/yyong1010/ethereumblocks',
      skew: 15000,
      assets: {
        erc721: 'https://api.thegraph.com/subgraphs/name/sunguru98/mainnet-erc721-subgraph',
        erc1155: 'https://api.thegraph.com/subgraphs/name/sunguru98/mainnet-erc1155-subgraph',
      },
    },
    'eip155:4': {
      blocks: 'https://api.thegraph.com/subgraphs/name/mul53/rinkeby-blocks',
      skew: 15000,
      assets: {
        erc721: 'https://api.thegraph.com/subgraphs/name/sunguru98/erc721-rinkeby-subgraph',
        erc1155: 'https://api.thegraph.com/subgraphs/name/sunguru98/erc1155-rinkeby-subgraph',
      },
    },
  },
}

// getResolver will return an object with a key/value pair of { 'nft': resolver }
// where resolver is a function used by the generic did resolver.
const nftResolver = getResolver(config)
const didResolver = Resolver(nftResolver)

const erc721result = await didResolver.resolve(
  'did:nft:eip155:1_erc721:0xb300a43751601bd54ffee7de35929537b28e1488_2'
)
const erc1155result = await didResolver.resolve(
  'did:nft:eip155:1_erc1155:0x06eb48572a2ef9a3b230d69ca731330793b65bdc_1'
)
console.log(erc721result, erc1155result)

chains field in config has CAIP-2 chain identifiers as keys. Each such chain is expected to contain endpoints to ERC721 and/or ERC1155 subgraphs under assets field. Both ERC721 and ERC1155 are supported. Feel free to specify either one or both.

The resolver supports the following networks by default:

• Ethereum mainnet (eip155:1),
• Ethereum Rinkeby (eip155:4),
• Polygon (formerly Matic) (eip155:137).

If you use one of those, you do not have to provide chains field.

Testing

$ npm test

Custom Subgraphs

You may specify custom subgraph URLs in the configuration object as shown above in usage.

Note: custom subgraphs must conform to the below schemas at a minimum for assets to be resolved properly.

Note: At the moment, only ERC721 and ERC1155 asset namespaces are supported. However, CAIP2 chains beside ETH, for instance xDAI, with support for those namespaces are supported, as long as the subgraph schema is the same.

ERC721:

type Token @entity {
  id: ID!
  contract: TokenContract!
  owner: Owner!
  ...
}

type TokenContract @entity {
  id: ID!
  tokens: [Token!]! @derivedFrom(field: "contract")
  ...
}

type Owner @entity {
  id: ID!
  tokens: [Token!]! @derivedFrom(field: "owner")
  ...
}

ERC1155:

type Account @entity {
  id: ID!
  balances: [Balance!]! @derivedFrom(field: "account")
  ...
}

type TokenRegistry @entity {
  id: ID!
  tokens: [Token!]! @derivedFrom(field: "registry")
  ...
}

type Token @entity {
  id: ID!
  registry: TokenRegistry!
  identifier: BigInt!
  balances: [Balance!]! @derivedFrom(field: "token")
  ...
}

type Balance @entity {
  id: ID!
  token: Token!
  account: Account!
  ...
}

For more information on writing schemas for GraphProtocol, check out their documentation.

DID Specs

The token DIDs are prefixed with did:nft:, and the latter half is a modified CAIP format.

ERC721 (CAIP-22)

DID: did:nft:{chainNamespace}:{chainReference}_erc721:{contractAddress}_{tokenId}

CAIP-22: {chainNamespace}:{chainReference}/erc721:{contractAddress}/{tokenId}

ERC1155 (CAIP-29)

DID: did:nft:{chainNamespace}:{chainReference}_erc1155:{contractAddress}_{tokenId}

CAIP-29: {chainNamespace}:{chainReference}/erc1155:{contractAddress}/{tokenId}

Conversions

DID->CAIP

const caip = did.substr(8).replace(/_/g, '/')

CAIP->DID

const did = `did:nft:${caip.replace(/\//g, '_')

There are helpers that help you with the conversion:

import { caipToDid, didToCaip, createNftDidUrl } from 'nft-did-resolver'
import { AssetId } from 'caip'

// CAIP -> DID URL
const didUrl = createNftDidUrl({
  chainId: 'eip155:1',
  namespace: 'erc721',
  contract: '0x1234567891234567891234567891234596351156'
  tokenId: '1',
})
// If you use `caip` library in your app, consider using sister `caipToDid` function to convert `AssetId` to NFT DID URL.

// DID URL -> CAIP
const assetId1 = didToCaip(didUrl) // eip155:1/erc721:0x1234567891234567891234567891234596351156/1
const assetId2 = didToCaip(didUrlWithTimestamp) // eip155:1/erc721:0x1234567891234567891234567891234596351156/1

Contributing

We are happy to accept small and large contributions. Make sure to check out the Ceramic specifications for details of how the protocol works.

License

Apache-2.0 OR MIT