PublicResolver

The default public resolver.

Source

PublicResolver implements a general-purpose LNS resolver that is suitable for most standard LNS use-cases. The public resolver permits updates to LNS records by the owner of the corresponding name.

The public resolver implements the following EIPs:

  • EIP 137 - Contract address interface (addr()).

  • EIP 165 - Interface Detection (supportsInterface()).

  • EIP 181 - Reverse resolution (name()).

  • EIP 205 - ABI support (ABI()).

  • EIP 619 - SECP256k1 public keys (pubkey()).

  • EIP 634 - Text records (text()).

  • EIP 1577 - Content hash support (contenthash()).

  • EIP 2304 - Multicoin support (addr()).

While the PublicResolverprovides a convenient default implementation, many resolver implementations and versions exist. Callers must not assume that a domain uses the current version of the public resolver, or that all of the methods described here are present. To check if a resolver supports a feature, see Check Interface Support.

Check Interface Support

function supportsInterface(bytes4 interfaceID) external pure returns (bool)

LNS uses ERC 165 for interface detection. ERC 165 requires that supporting contracts implement a function, supportsInterface, which takes an interface ID and returns a boolean value indicating if this interface is supported or not.

Interface IDs are calculated as the exclusive-or of the four-byte function identifiers of each function included in the interface. For example, addr(bytes32) has the function ID 0x3b3b57de. Because it is the only function in the smartBCH Address interface, its interface ID is also 0x3b3b57de, and so calling supportsInterface(0x3b3b57de) will return true for any resolver that supports addr().

ERC 165 has an interface ID of 0x01ffc9a7, so supportsInterface(0x01ffc9a7) will always return true for any ERC 165 supporting contract (and hence for any resolver).

Note that the public resolver does not expose explicit interfaces for setter functions, so there are no automated means to check for support for a given setter function.

Get smartBCH Address

function addr(bytes32 node) external view returns (address)

Returns the smartBCH address associated with the provided node, or 0 if none.

This function has interface ID 0x3b3b57de.

This function is specified in EIP 137.

Set smartBCH Address

function setAddr(bytes32 node, address addr) external;

Sets the smartBCH address associated with the provided node to addr.

Only callable by the owner of node.

Emits the following event:

event AddrChanged(bytes32 indexed node, address a);

Get Blockchain Address

function addr(bytes32 node, uint coinType) external view returns(bytes memory);

Returns the Blockchain address associated with the provided node and coinType, or 0 if none.

This function has interface ID 0xf1cb7e06.

This function is specified in EIP 2304.

The return value is the cryptocurrency address in its native binary format and each blockchain address has a different encoding and decoding method.

For example, the Bitcoin address 1A1zP1eP5QGefi2DMPTfTL5SLmv7DivfNa base58check decodes to the 21 bytes 0062e907b15cbf27d5425399ebf6f0fb50ebb88f18 then scriptPubkey encodes to 25 bytes 76a91462e907b15cbf27d5425399ebf6f0fb50ebb88f1888ac whereas the BNB address bnb1grpf0955h0ykzq3ar5nmum7y6gdfl6lxfn46h2 Bech32 decodes to the binary representation 40c2979694bbc961023d1d27be6fc4d21a9febe6.

To convert the binary representation into the address, use formatsByCoinType[SYMBOL].encoder(binary) of address-encoder.

A zero-length string will be returned if the specified coin ID does not exist on the specified node.

Set Blockchain Address

function setAddr(bytes32 node, uint coinType, bytes calldata a) external;

Sets the blockchain address associated with the provided node and coinType to addr.

coinType is the cryptocurrency coin type index from SLIP44.

To convert the address into the binary representation, use formatsByName[SYMBOL].decoder(text) of address-encoder

Only callable by the owner of node.

Emits the following event:

event AddressChanged(bytes32 indexed node, uint coinType, bytes newAddress);

Get Canonical Name

function name(bytes32 node) external view returns (string memory);

Returns the canonical LNS name associated with the provided node. Used exclusively for reverse resolution.

This function has interface ID 0x691f3431.

This function is specified in EIP 181.

Set Canonical Name

function setName(bytes32 node, string calldata name) external;

Sets the canonical LNS name for the provided node to name.

Only callable by the owner of node.

Emits the following event:

event NameChanged(bytes32 indexed node, string name);

Get Content Hash

function contenthash(bytes32 node) external view returns (bytes memory);

Returns the content hash for node, if one exists. Values are formatted as machine-readable multicodecs, as specified in EIP 1577.

contenthash is used to store IPFS and Swarm content hashes, which permit resolving LNS addresses to distributed content (eg, websites) hosted on these distributed networks.

This function has interface ID 0xbc1c58d1.

This function is specified in EIP 1577.

Set Content Hash

function setContenthash(bytes32 node, bytes calldata hash) external;

Sets the content hash for the provided node to hash.

Only callable by the owner of node.

Values are formatted as machine-readable multicodecs, as specified in EIP 1577.

Emits the following event:

event ContenthashChanged(bytes32 indexed node, bytes hash);

Get Contract ABI

ABI(bytes32 node, uint256 contentTypes) external view returns (uint256, bytes memory);

Returns a matching ABI definition for the provided node, if one exists. contentTypes is the bitwise-OR of the encodings that the caller can accept. If multiple content types are specified, the resolver will select one to return. Currently supported content types are:

Content Type ID
Description

1

JSON

2

zlib-compressed JSON

4

8

URI

ABI returns a two-tuple of the content type ID and the ABI data. If no data of the appropriate content type ID was found, 0 is returned for the content type ID, and the ABI data will be the empty string.

This function has interface ID 0x2203ab56.

This function is specified in EIP 205.

Set Contract ABI

function setABI(bytes32 node, uint256 contentType, bytes calldata data) external

Sets or updates ABI data for node. contentType specifies the content type ID (see Get Contract ABI for valid values); exactly one type ID must be specified. data contains the encoded ABI data. To clear ABI data for a name, specify the empty string for data.

Only callable by the owner of node.

Emits the following event:

event ABIChanged(bytes32 indexed node, uint256 indexed contentType);

Get Public Key

function pubkey(bytes32 node) external view returns (bytes32 x, bytes32 y)

Returns the ECDSA SECP256k1 public key for node, as a 2-tuple (x, y). If no public key is set, (0, 0) is returned.

This function has interface ID 0xc8690233.

This function is specified in EIP 619.

Set Public Key

function setPubkey(bytes32 node, bytes32 x, bytes32 y) external

Sets the ECDSA SECP256k1 public key for node to (x, y).

Only callable by the owner of node.

Emits the following event:

event PubkeyChanged(bytes32 indexed node, bytes32 x, bytes32 y);

Get Text Data

function text(bytes32 node, string calldata key) external view returns (string memory)

Retrieves text metadata for node. Each name may have multiple pieces of metadata, identified by a unique string key. If no text data exists for node with the key key, the empty string is returned.

Standard values for key are:

key
Meaning

email

An email address

url

A URL

avatar

A URL to an image used as an avatar or logo

description

A description of the name

notice

A notice regarding this name

keywords

A list of comma-separated keywords, ordered by most significant first; clients that interpresent this field may choose a threshold beyond which to ignore

In addition, anyone may specify vendor-specific keys, which must be prefixed with vnd.. The following vendor-specific keys are currently known:

key
Meaning

com.twitter

Twitter handle

com.github

Github username

This function has interface ID 0x59d1d43c.

This function is specified in EIP 634.

Set Text Data

function setText(bytes32 node, string calldata key, string calldata value) external

Sets text metadata for node with the unique key key to value, overwriting anything previously stored for node and key. To clear a text field, set it to the empty string.

Only callable by the owner of node.

Emits the following event:

event TextChanged(bytes32 indexed node, string indexedKey, string key);

Multicall

function multicall(bytes[] calldata data) external returns(bytes[] memory results)

Permits users to set multiple records in a single operation.

Use encodeABI function to encode your contract calls and pass it to data.

The frontend usage will be as follows:

var addrSet = resolver.contract.methods['setAddr(bytes32,address)'](node, accounts[1]).encodeABI();
var textSet = resolver.contract.methods.setText(node, "url", "https://ethereum.org/").encodeABI();
var tx = await resolver.multicall([addrSet, textSet], {from: accounts[0]});
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