142 lines
4.6 KiB
Rust
142 lines
4.6 KiB
Rust
//! [Ethereum Name Service](https://docs.ens.domains/) support
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//! Adapted from <https://github.com/hhatto/rust-ens/blob/master/src/lib.rs>
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use ethers_core::{
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types::{Address, NameOrAddress, Selector, TransactionRequest, H160, H256},
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utils::keccak256,
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};
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use std::convert::TryInto;
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/// ENS registry address (`0x00000000000C2E074eC69A0dFb2997BA6C7d2e1e`)
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pub const ENS_ADDRESS: Address = H160([
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// cannot set type aliases as constructors
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0, 0, 0, 0, 0, 12, 46, 7, 78, 198, 154, 13, 251, 41, 151, 186, 108, 125, 46, 30,
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]);
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// Selectors
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const ENS_REVERSE_REGISTRAR_DOMAIN: &str = "addr.reverse";
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/// resolver(bytes32)
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const RESOLVER: Selector = [1, 120, 184, 191];
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/// addr(bytes32)
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pub const ADDR_SELECTOR: Selector = [59, 59, 87, 222];
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/// name(bytes32)
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pub const NAME_SELECTOR: Selector = [105, 31, 52, 49];
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/// text(bytes32, string)
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pub const FIELD_SELECTOR: Selector = [89, 209, 212, 60];
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/// supportsInterface(bytes4 interfaceID)
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pub const INTERFACE_SELECTOR: Selector = [1, 255, 201, 167];
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/// Returns a transaction request for calling the `resolver` method on the ENS server
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pub fn get_resolver<T: Into<NameOrAddress>>(ens_address: T, name: &str) -> TransactionRequest {
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// keccak256('resolver(bytes32)')
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let data = [&RESOLVER[..], &namehash(name).0].concat();
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TransactionRequest {
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data: Some(data.into()),
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to: Some(ens_address.into()),
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..Default::default()
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}
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}
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/// Returns a transaction request for checking interface support
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pub fn supports_interface<T: Into<NameOrAddress>>(
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resolver_address: T,
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selector: Selector,
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) -> TransactionRequest {
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let data = [&INTERFACE_SELECTOR[..], &selector[..], &[0; 28]].concat();
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TransactionRequest {
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data: Some(data.into()),
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to: Some(resolver_address.into()),
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..Default::default()
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}
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}
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/// Returns a transaction request for calling
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pub fn resolve<T: Into<NameOrAddress>>(
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resolver_address: T,
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selector: Selector,
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name: &str,
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parameters: Option<&[u8]>,
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) -> TransactionRequest {
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let data = [&selector[..], &namehash(name).0, parameters.unwrap_or_default()].concat();
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TransactionRequest {
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data: Some(data.into()),
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to: Some(resolver_address.into()),
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..Default::default()
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}
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}
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/// Returns the reverse-registrar name of an address.
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pub fn reverse_address(addr: Address) -> String {
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format!("{addr:?}.{ENS_REVERSE_REGISTRAR_DOMAIN}")[2..].to_string()
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}
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/// Returns the ENS namehash as specified in [EIP-137](https://eips.ethereum.org/EIPS/eip-137)
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pub fn namehash(name: &str) -> H256 {
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if name.is_empty() {
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return H256::zero()
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}
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// iterate in reverse
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name.rsplit('.')
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.fold([0u8; 32], |node, label| keccak256([node, keccak256(label.as_bytes())].concat()))
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.into()
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}
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/// Returns a number in bytes form with padding to fit in 32 bytes.
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pub fn bytes_32ify(n: u64) -> Vec<u8> {
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let b = n.to_be_bytes();
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[[0; 32][b.len()..].to_vec(), b.to_vec()].concat()
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}
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/// Returns the ENS record key hash [EIP-634](https://eips.ethereum.org/EIPS/eip-634)
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pub fn parameterhash(name: &str) -> Vec<u8> {
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let bytes = name.as_bytes();
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let key_bytes =
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[&bytes_32ify(64), &bytes_32ify(bytes.len().try_into().unwrap()), bytes].concat();
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match key_bytes.len() % 32 {
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0 => key_bytes,
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n => [key_bytes, [0; 32][n..].to_vec()].concat(),
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}
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}
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#[cfg(test)]
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mod tests {
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use super::*;
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fn assert_hex(hash: H256, val: &str) {
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let v = if let Some(stripped) = val.strip_prefix("0x") { stripped } else { val };
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assert_eq!(hash.0.to_vec(), hex::decode(v).unwrap());
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}
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#[test]
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fn test_namehash() {
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for (name, expected) in &[
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("", "0000000000000000000000000000000000000000000000000000000000000000"),
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("foo.eth", "de9b09fd7c5f901e23a3f19fecc54828e9c848539801e86591bd9801b019f84f"),
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("eth", "0x93cdeb708b7545dc668eb9280176169d1c33cfd8ed6f04690a0bcc88a93fc4ae"),
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("alice.eth", "0x787192fc5378cc32aa956ddfdedbf26b24e8d78e40109add0eea2c1a012c3dec"),
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] {
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assert_hex(namehash(name), expected);
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}
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}
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#[test]
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fn test_parametershash() {
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assert_eq!(
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parameterhash("avatar").to_vec(),
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vec![
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0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
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0, 0, 0, 64, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
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0, 0, 0, 0, 0, 0, 0, 0, 6, 97, 118, 97, 116, 97, 114, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
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0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
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]
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);
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}
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}
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