chore: simplify eip712 example (#492)

* chore(contract): gate eip712

* examples: simplify permit hash

* chore: fmt

Cargo.toml

@@ -81,7 +81,7 @@ ethers-signers = { version = "^0.5.0", default-features = false, path = "./ether
 ethers-middleware = { version = "^0.5.0", default-features = false, path = "./ethers-middleware" }
 
 [dev-dependencies]
-ethers-contract = { version = "^0.5.0", default-features = false, path = "./ethers-contract", features = ["abigen"] }
+ethers-contract = { version = "^0.5.0", default-features = false, path = "./ethers-contract", features = ["abigen", "eip712"] }
 ethers-providers = { version = "^0.5.0", default-features = false, path = "./ethers-providers", features = ["ws", "ipc"] }
 
 anyhow = "1.0.39"
@@ -90,4 +90,4 @@ serde = { version = "1.0.124", features = ["derive"] }
 serde_json = "1.0.64"
 tokio = { version = "1.5", features = ["macros", "rt-multi-thread"] }
 hex = "0.4.3"
-bytes = "1.1.0"
+bytes = "1.1.0"

ethers-contract/Cargo.toml

@@ -11,9 +11,10 @@ keywords = ["ethereum", "web3", "celo", "ethers"]
 
 [dependencies]
 ethers-providers = { version = "^0.5.0", path = "../ethers-providers", default-features = false }
-ethers-core = { version = "^0.5.0", path = "../ethers-core", default-features = false, features = ["eip712"]}
+ethers-core = { version = "^0.5.0", path = "../ethers-core", default-features = false }
 ethers-contract-abigen = { version = "^0.5.0", path = "ethers-contract-abigen", optional = true }
 ethers-contract-derive = { version = "^0.5.0", path = "ethers-contract-derive", optional = true }
+ethers-derive-eip712 = { version = "0.1.0", path = "../ethers-core/ethers-derive-eip712", optional = true }
 
 serde = { version = "1.0.124", default-features = false }
 serde_json = { version = "1.0.64", default-features = false }
@@ -29,12 +30,14 @@ ethers-providers = { version = "^0.5.0", path = "../ethers-providers", default-f
 ethers-signers = { version = "^0.5.0", path = "../ethers-signers" }
 ethers-contract-abigen = { version = "^0.5.0", path = "ethers-contract-abigen" }
 ethers-contract-derive = { version = "^0.5.0", path = "ethers-contract-derive" }
+ethers-core = { version = "^0.5.0", path = "../ethers-core", default-features = false, features = ["eip712"]}
 ethers-derive-eip712 = { version = "0.1.0", path = "../ethers-core/ethers-derive-eip712"}
 
 [target.'cfg(not(target_arch = "wasm32"))'.dev-dependencies]
 tokio = { version = "1.5", default-features = false, features = ["macros"] }
 
 [features]
+eip712 = ["ethers-derive-eip712", "ethers-core/eip712"]
 abigen = ["ethers-contract-abigen", "ethers-contract-derive"]
 celo = ["legacy", "ethers-core/celo", "ethers-core/celo", "ethers-providers/celo"]
 legacy = []

examples/permit_hash.rs

@@ -1,94 +1,36 @@
 use ethers::{
-    abi,
+    contract::Eip712,
-    abi::Token,
+    contract::EthAbiType,
-    prelude::U256,
+    core::types::transaction::eip712::Eip712,
-    types::Address,
+    types::{Address, U256},
-    utils,
-    utils::{keccak256, parse_ether},
 };
 
-const UNISWAP_V2_USDC_ETH_PAIR: &'static str = "0xB4e16d0168e52d35CaCD2c6185b44281Ec28C9Dc";
-
 // Generate the EIP712 permit hash to sign for a Uniswap V2 pair.
 // https://eips.ethereum.org/EIPS/eip-712
 // https://eips.ethereum.org/EIPS/eip-2612
-fn main() {
+#[derive(Eip712, EthAbiType, Clone)]
-    // Test data
+#[eip712(
-    let owner: Address = "0x617072Cb2a1897192A9d301AC53fC541d35c4d9D"
+    name = "Uniswap V2",
-        .parse()
+    version = "1",
-        .unwrap();
+    chain_id = 1,
-    let spender: Address = "0x2819c144D5946404C0516B6f817a960dB37D4929"
+    verifying_contract = "0xB4e16d0168e52d35CaCD2c6185b44281Ec28C9Dc"
-        .parse()
+)]
-        .unwrap();
+struct Permit {
-    let value = parse_ether(10).unwrap();
+    owner: Address,
-    let nonce = U256::from(1);
+    spender: Address,
-    let deadline = U256::from(3133728498 as u32);
+    value: U256,
-    let verifying_contract: Address = UNISWAP_V2_USDC_ETH_PAIR.parse().unwrap();
+    nonce: U256,
-    let name = "Uniswap V2";
+    deadline: U256,
-    let version = "1";
+}
-    let chainid = 1;
+
-
+fn main() {
-    // Typehash for the permit() function
+    let permit = Permit {
-    let permit_typehash = utils::keccak256(
+        owner: Address::random(),
-        "Permit(address owner,address spender,uint256 value,uint256 nonce,uint256 deadline)",
+        spender: Address::random(),
-    );
+        value: 100.into(),
-    // Typehash for the struct used to generate the domain separator
+        nonce: 0.into(),
-    let domain_typehash = keccak256(
+        deadline: U256::MAX,
-        "EIP712Domain(string name,string version,uint256 chainId,address verifyingContract)",
+    };
-    );
+    let permit_hash = permit.encode_eip712().unwrap();
-
+    println!("Permit hash: 0x{}", hex::encode(permit_hash));
-    // Corresponds to solidity's abi.encode()
-    let domain_separator_input = abi::encode(&vec![
-        Token::Uint(U256::from(domain_typehash)),
-        Token::Uint(U256::from(keccak256(&name))),
-        Token::Uint(U256::from(keccak256(&version))),
-        Token::Uint(U256::from(chainid)),
-        Token::Address(verifying_contract),
-    ]);
-
-    // Corresponds to the following solidity:
-    // DOMAIN_SEPARATOR = keccak256(
-    //     abi.encode(
-    //         keccak256('EIP712Domain(string name,string version,uint256 chainId,address verifyingContract)'),
-    //         keccak256(bytes(name)),
-    //         keccak256(bytes('1')),
-    //         chainId,
-    //         address(this)
-    //     )
-    // );
-    let domain_separator = keccak256(&domain_separator_input);
-
-    // Corresponds to solidity's abi.encode()
-    let struct_input = abi::encode(&vec![
-        Token::Uint(U256::from(permit_typehash)),
-        Token::Address(owner),
-        Token::Address(spender),
-        Token::Uint(value),
-        Token::Uint(nonce),
-        Token::Uint(deadline),
-    ]);
-    let struct_hash = keccak256(&struct_input);
-
-    // Corresponds to solidity's abi.encodePacked()
-    let digest_input = [
-        &[0x19, 0x01],
-        domain_separator.as_ref(),
-        struct_hash.as_ref(),
-    ]
-    .concat();
-
-    // Matches the following solidity:
-    // bytes32 digest = keccak256(
-    //     abi.encodePacked(
-    //         '\x19\x01',
-    //         DOMAIN_SEPARATOR,
-    //         keccak256(abi.encode(PERMIT_TYPEHASH, owner, spender, value, nonces[owner]++, deadline))
-    //     )
-    // );
-    let permit_hash = keccak256(&digest_input);
-
-    assert_eq!(
-        hex::encode(permit_hash),
-        "7b90248477de48c0b971e0af8951a55974733455191480e1e117c86cc2a6cd03"
-    );
 }