40 lines
2.1 KiB
Markdown
40 lines
2.1 KiB
Markdown
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# Contracts
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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.
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## Generating Rust bindings with abigen
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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.
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### Generate a Rust file
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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.
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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.
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```rust
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Abigen::new("ERC20Token", "./abi.json")?.generate()?.write_to_file("token.rs")?;
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```
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### Generate inline Rust bindings
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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.
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Running the code below will generate bindings for the `ERC20Token` struct, along with all its events and methods.
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```rust
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abigen!(
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ERC20Token,
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r#"[
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function approve(address spender, uint256 amount) external returns (bool)
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event Transfer(address indexed from, address indexed to, uint256 value)
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event Approval(address indexed owner, address indexed spender, uint256 value)
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]"#,
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);
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```
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Another way to get the same result, is to provide the ABI contract's definition as follows.
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```rust
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abigen!(ERC20Token, "./abi.json",);
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```
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## Contract instances
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## Contract methods
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## Contract events
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