Lib.rs

Solidity

A Solidity encoding and decoding framework for Rust.

// Basic usage using the built in `Encode` derive macro.
// (Requires the `derive` feature.)
#[derive(Encode)]
struct ContractCallEncode<'a> {
    pub name: &'a str,
    pub number: u128,
    pub bytes10: Bytes10,
    pub bytes: Bytes<'a>,
}

// Basic usage using serde. (Requires the `serde` feature).
// Note: Serde only supports a subset of the types that Solidity supports.
// If you need to support more types you'll have to use the `Encode` derive
// macro, or use the `solid::Builder` manually.
#[derive(Serialize)]
pub struct ContractCallSerde<'a> {
    // String is also supported, but it's recommened you use &str when possible.
    // pub name: String,
    pub name: &'a str,
    pub number: u128,
    pub bytes: Bytes<'a>,
    // Bytes10 cannot be serialized correctly using serde.
    // pub bytes: Bytes10,
}

// Use the `#[solid(constructor)]` attribute to declare a struct as a constructor.
// This is important because constructors do not have the function name prefix,
// unlike all other functions. Usually the struct name is used as the function
// name. To rename the function use the `#[solid(name = "<function_name>")]`
// where `<function_name>` is the name of your function.
// ie. `#[solid(name = "transfer")]`.
#[derive(Encode)]
struct ContractConstructorEncode<'a> {
    pub value: u128,
    pub string: &'a str,
}

// Basic usage with the built in `Decode` derive macro.
// (Requires the `derive` feature.)
// Note: `Uint256` and all other `Int`/`Uint` types are simple
// wrappers around `[u8; 32]`. The point of them is to support all
// `int`/`uint` Solidity types.
#[derive(Decode)]
#[solid(error)]
struct ContractCallResponse<'a> {
    int: Uint256,
    // Note: &'a [u8] is *not* the same as `Bytes<'a>`. The former is is `uint8[]` in solidity
    // while the latter is `bytes`. The two types are encoded very differently so decoding
    // `bytes` as `uint8[]` array will give you invalid data if not fail outright.
    bytes: Bytes<'a>,
    memo: &'a str,
    address: Address,
}

// Basic usage with serde's `Deserialize` derive macro.
// (Requires the `serde` feature.)
// Note: Serde only supports a subset of the types that Solidity supports.
// If you need to support more types you'll have to use the `Encode` derive
// macro, or use the `solid::Builder` manually.
#[derive(Deserialize)]
struct ContractCallResponseSerde<'a> {
    int: u128,
    bytes: &'a [u8],
    memo: &'a str,
    // There is no way to read `Address` with serde.
    // address: Address
}

// Support for composite types and `Vec`
#[derive(Encode)]
struct ContractCallComposite<'a> {
    to: (&'a str, u128),
    memos: &'a [&'a str],
    matrix: &'a [&'a [&'a [u8]]],
}

// If you want to manually build the contract you can use the provided `Builder`
let function = Builder::new()
    .name("transfer")
    .push("daniel")
    .push(10u128)
    .push(Bytes10([1u8; 10]))
    .build();

num_bigint Support

If you'd like support for num_bigint enable the bigint feature.

// Note: BigInt is variable sized and encodes to `int256`.
// To encode to `uint256` use the `BigUint` struct.
// Also, BigInt supports numbers larger than the max value a uint256 can store, so the value
// will be truncated to 32 bytes before it's encoded.
#[derive(Encode)]
#[solid(rename = "transfer")]
struct ContractTransfer<'a> {
    amount: BigInt,
    to: &'a str
}

ethereum_types Support

If you'd like support for ethereum_types enable the ethereum_types feature.

// Support for Address, U256, U128 from `ethereum_types` crate.
#[derive(Encode)]
#[solid(rename = "transfer")]
struct ContractTransfer<'a> {
    amount: ethereum_types::U256,
    to: ethereum_types::Address,
}

Install

# Cargo.toml

# Default features which includes `derive`, and `serde`
solid = "0.1.4"

# num_bigint support
solid = { version = "0.1.4", default-features = false, features = [ "derive", "serde", "bigint" ] }

# ethereum_types support
solid = { version = "0.1.4", default-features = false, features = [ "derive", "serde", "ethereum_types" ] }

Using cargo-edit

cargo add solid

Features

• derive: Add support for the Encode and Decode derive macros. (Recommended)
• derse: Add support for serdes Serialize and Deserialize derive macros, and to_bytes function.
• bigint: Add suport for num_bigint crate.
• ethereum_types: Add support for ethereum_types crate.
• nightly: Experimental const generic support.

cargo-solid Subcommand

cargo-solid is a cargo subcommand that allows you to generate the encoding functions and decodable struct definitions for named return types of associated Solidity methods. example

Subcommand Install

cargo install cargo-solid

The following command generates the solidity abi for a contract.

solc --combined-json abi solidity_contract.sol > solidity_contract.json

Then run the following command to generate the rust definition.

cargo solid solidity_contract.json

The name of the output file will the be same name as the input file with the extension set to .rs, and will be located in the local src directory. You can freely move the file if you would like, but either way you will still need to add the file as a module:

mod solidity_contract;

As of version cargo-solidv0.1.4 you can also generate the files into a directory such as src/generated, and there is also support for generating code using nightly definitions of BytesFix and Int.

cargo solid --nightly -o generated stateful.json

example