ethcontract 0.25.8

Generate bindings for Ethereum smart contracts. Internally, the generated types use web3 crate to interact with the Ethereum network and uses a custom Instance runtime that can be used directly without code generation.

This crate is using std::future::Future for futures by wrapping web3 futures 0.1 with futures 0.3 compatibility layer. This means that this crate is ready for async/await!

Here is an example of interacing with a smart contract MyContract. The builder pattern is used for configuring transactions.

pragma solidity ^0.6.0;

contract MyContract {
  function my_view_function(uint64 some_val) public view returns (string) {
    // ...
  }

  function my_function(bool some_bool, string some_str) public returns (uint256) {
    // ...
  }

  function my_other_function() public {
    // ...
  }
}

Once this contract is built and deployed with truffle the following example demonstrates how to interact with it from Rust.

use ethcontract::transaction::Account;
use std::time::Duration;
use web3::api::Web3;
use web3::types::*;

// this proc macro generates a `MyContract` type with type-safe bindings to
// contract functions
ethcontract::contract!("path/to/MyContract.json");

// create a web3 instance as usual
let transport = ...;
let web3 = Web3::new(transport);

// now create an instance of an interface to the contract
let instance = MyContract::deployed(web3).await?;

let addr: Address = "0x000102030405060708090a0b0c0d0e0f10111213".parse()?;
let some_uint: U256 = U256::from_dec_str("1000000000000000000")?;
let some_bool = true;
let some_val = u64;

// call instance view functions with type-safe bindings! will only compile
// if contract function accepts a single `u64` value parameter and returns
// a concrete type based on the contract function's return type
let value = instance
    .my_view_function(some_val)
    .from(addr)
    .execute()
    .await?;

// contract functions also have type-safe bindings and return the tx hash
// of the submitted transaction; allows for multiple ways of signing txs
let tx = instance
    .my_function(some_bool, value)
    .from(Account::Locked(addr, "password".into(), None))
    .value(some_uint)
    .gas_price(1_000_000.into())
    .execute()
    .await?;

// wait for confirmations when needed
let receipt = instance
    .my_important_function()
    .poll_interval(Duration::from_secs(5))
    .confirmations(2)
    .execute_confirm()
    .await?;

See contract! proc macro documentation for more information on usage and parameters as well on how to use contract ABI directly from Etherscan.