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.

$3

``
$ npm install nft-did-resolver
`

$3

`typescript
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.

$3

`gql
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")
...
}

`

$3

`gql
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}

$3

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:

`typescript
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