Story

Package originally created by thojest and later maintained by ZGEN DAO. Created with the purpose to provide a simple alternative for Web3 packages written in Rust.

Description

Ethane is an alternative Web3 implementation with the aim of being slim and simple. It has two features blocking and non-blocking that determines the http connection type it should use.

A blocking http client does not depend on futures or any executors. Furthermore, it currently supports websockets (both plain and TLS) and inter process communication via Unix domain sockets (Unix only). For http and websockets it also supports Http Basic and Bearer Authentication. It also has a built-in ABI parser library. It's hidden under the contract functionalities, but it can be used alongside with the main crate.

If you still need a non-blocking http client (e.g. for wasm compatibility), you may compile Ethane with the non-blocking feature flag to enable an async http client.

Please also take a look at the documentation. If you just want to use this crate, it is also available on crates.io. (Ethane). If you find any bugs please do not hesitate to open an issue.

Usage

Guidelines to use the Ethane library. The examples were worked out for the blocking client, however the non-blocking version is quite similar. The main difference is that an AsyncConnection can only wrap an AsyncHttp client without any type generics, so there is currently no implementation for a non-blocking websocket.

Connection

Everything starts with a connection.

use ethane::{Connection, Http, WebSocket};

fn main() {
    let conn = Connection::new(Http::new("http://localhost:8545", None));
    // or
    let conn = Connection::new(WebSocket::new("ws://localhost:8546", None));
}

Methods

After we have connected to the Ethereum Network we can call several methods. More details on the supported methods later.

use ethane::{Connection, Http};
use ethane::types::Address;

fn main() {
    let conn = Connection::new(Http::new("http://localhost:8545", None));
    
    match conn.call(rpc::eth_get_balance(Address::try_from_str(ADDRESS1).unwrap(), None)) {
        Ok(res) => res,
        Err(err) => println!("{:?}", err),
    }
}

Contract call

The library supports contract calls as well via ethane-abi.

use ethane::{Connection, Http};
use ethane::contract::{CallOpts, CallResult, Caller};
use ethane::types::{Address, U256};
use ethane_abi::Parameter;

fn main() {
    let conn = Connection::new(Http::new("http://localhost:8545", None));

    let mut caller = Caller::new_from_path(
        conn,
        "path/to/contract.abi",
        Address::try_from_str("0x141770c471a64bcde74c587e55a1ffd9a1bffd31").unwrap(),
    );

    // The call function determine the call_type based on the state_mutability.
    // This calls to function from an ERC-20 compliant token
    // eth_call
    let address = Address::try_from_str("0x141770c471a64bcde74c587e55a1ffd9a1bffd31").uwnrap();
    let result = caller.call(
        "balanceOf",
        vec![Parameter::from(address)],
        None,
    );
    match result {
        CallResult::Transaction(_) => panic!("Should be eth_call"),
        CallResult::Call(r) => match r[0] {
            Parameter::Uint(data, 256) => assert_eq!(data, H256::from_int_unchecked(1000000000_u64)),
            _ => panic!("Invalid data received!"),
        },
    }

    // eth_sendTransaction
    let to_address = Address::try_from_str("0x...").unwrap();
    let result = caller.call(
        "transfer",
        vec![
            Parameter::from(to_address),
            Parameter::from(U256::try_from_int(1000_u128).unwrap()),
        ],
        Some(CallOpts {
            force_call_type: None, // NOTE: the call_type can be forced
            from: Some(address),
        }),
    );
    match result {
        CallResult::Call(_) => panic!("Should be a transaction"),
        CallResult::Transaction(tx_hash) => println!("{}", tx_hash),
    }
}

Subscribe

Subscription has a different connection method.

use ethane::{Connection, WebSocket};

fn main() {
    let conn = Connection::new(WebSocket::new("ws://localhost:8546", None));
    let mut tx_subscription = conn.subscribe(eth_subscribe_new_pending_transactions()).unwrap();

    // Get next transaction item
    let tx = tx_subscription.next_item().unwrap();
}

Contribution

Issues and PRs are warmly welcomed. Development follows the OSS standard.