web3

Ethereum JSON-RPC multi-transport client. Rust implementation of Web3.js library.

Documentation: crates.io

Status

Note this package is barely maintained and I am looking for an active maintainer (see #664). If you are starting a new project, I'd recommend choosing https://github.com/gakonst/ethers-rs instead.

Usage

First, add this to your Cargo.toml:

[dependencies]
web3 = "0.19.0"

Example

#[tokio::main]
async fn main() -> web3::Result<()> {
    let transport = web3::transports::Http::new("http://localhost:8545")?;
    let web3 = web3::Web3::new(transport);

    println!("Calling accounts.");
    let mut accounts = web3.eth().accounts().await?;
    println!("Accounts: {:?}", accounts);
    accounts.push("00a329c0648769a73afac7f9381e08fb43dbea72".parse().unwrap());

    println!("Calling balance.");
    for account in accounts {
        let balance = web3.eth().balance(account, None).await?;
        println!("Balance of {:?}: {}", account, balance);
    }

    Ok(())
}

If you want to deploy smart contracts you have written you can do something like this (make sure you have the solidity compiler installed):

solc -o build --bin --abi contracts/*.sol

The solidity compiler is generating the binary and abi code for the smart contracts in a directory called contracts and is being output to a directory called build.

For more see examples folder.

Futures migration

• Get rid of parking_lot (replace with async-aware locks if really needed).
• Consider getting rid of Unpin requirements. (#361)
• WebSockets: TLS support (#360)
• WebSockets: Reconnecting & Pings
• Consider using tokio instead of async-std for ws.rs transport (issue with test).
• Restore IPC Transport

General

• More flexible API (accept Into<X>)
• Contract calls (ABI encoding; debris/ethabi)
• Batch Requests

Transports

• HTTP transport
• IPC transport
• WebSockets transport

Types

• Types for U256,H256,Address(H160)
• Index type (numeric, encoded to hex)
• Transaction type (Transaction from Parity)
• Transaction receipt type (TransactionReceipt from Parity)
• Block type (RichBlock from Parity)
• Work type (Work from Parity)
• Syncing type (SyncStats from Parity)

APIs

• Eth: eth_*
• Eth filters: eth_*
• Eth pubsub: eth_*
• net_*
• web3_*
• personal_*
• traces_*

Parity-specific APIs

• Parity read-only: parity_*

• Parity accounts: parity_* (partially implemented)

• Parity set: parity_*

• signer_*

• Own APIs (Extendable)

let web3 = Web3::new(transport);
web3.api::<CustomNamespace>().custom_method().wait().unwrap()

Installation on Windows

Currently, Windows does not support IPC, which is enabled in the library by default. To compile, you need to disable the IPC feature:

web3 = { version = "0.19.0", default-features = false, features = ["http"] }

Avoiding OpenSSL dependency

On Linux, native-tls is implemented using OpenSSL. To avoid that dependency for HTTPS use the corresponding feature.

web3 = { version = "0.19.0", default-features = false, features = ["http-rustls-tls"] }

Cargo Features

The library supports following features:

• http - Enables HTTP transport (requires tokio runtime, because of hyper).
• http-tls - Enables TLS support via reqwest/default-tls for HTTP transport (implies http; default).
• http-native-tls - Enables TLS support via reqwest/native-tls for HTTP transport (implies http).
• http-rustls-tls - Enables TLS support via reqwest/rustls-tls for HTTP transport (implies http).
• ws-tokio - Enables WS transport using tokio runtime.
• ws-tls-tokio - Enables TLS support for WS transport (implies ws-tokio; default).
• ws-async-std - Enables WS transport using async-std runtime.
• ws-tls-async-std - Enables TLS support for WS transport (implies ws-async-std).
• ipc-tokio - Enables IPC transport using tokio runtime (default).
• signing - Enable account namespace and local-signing support (default).
• eip-1193 - Enable EIP-1193 support.
• wasm - Compile for WASM (make sure to disable default features).
• arbitrary_precision - Enable arbitrary_precision in serde_json.
• allow-missing-fields - Some response fields are mandatory in Ethereum but not present in EVM-compatible chains such as Celo and Fantom. This feature enables compatibility by setting a default value on those fields.