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README.md
Contracts
In this guide, we will go over some examples of using ethers-rs to work with contracts, including using abigen to generate Rust bindings for a contract, listening for contract events, calling contract methods, and instantiating contracts.
Generating Rust bindings with abigen
To use a contract with ethers-rs, you will need to generate Rust bindings using the abigen tool. abigen is included with the ethers-rs library and can be used to generate Rust bindings for any Solidity contract.
Generate a Rust file
This method takes a smart contract's Application Binary Interface (ABI) file and generates a Rust file to interact with it. This is useful if the smart contract is referenced in different places in a project. File generation from ABI can also be easily included as a build step of your application.
Running the code below will generate a file called token.rs containing the bindings inside, which exports an ERC20Token struct, along with all its events and methods. Put into a build.rs file this will generate the bindings during cargo build.
Abigen::new("ERC20Token", "./abi.json")?.generate()?.write_to_file("token.rs")?;
Generate inline Rust bindings
This method takes a smart contract's solidity definition and generates inline Rust code to interact with it. This is useful for fast prototyping and for tight scoped use-cases of your contracts. Inline Rust generation uses the abigen! macro to expand Rust contract bindings.
Running the code below will generate bindings for the ERC20Token struct, along with all its events and methods.
abigen!(
ERC20Token,
r#"[
function approve(address spender, uint256 amount) external returns (bool)
event Transfer(address indexed from, address indexed to, uint256 value)
event Approval(address indexed owner, address indexed spender, uint256 value)
]"#,
);
Another way to get the same result, is to provide the ABI contract's definition as follows.
abigen!(ERC20Token, "./abi.json",);