Trait ethers_middleware::builder::MiddlewareBuilder

source ·

pub trait MiddlewareBuilder: Middleware + Sized + 'static {
    // Provided methods
    fn wrap_into<F, T>(self, f: F) -> T
       where F: FnOnce(Self) -> T,
             T: Middleware { ... }
    fn with_signer<S>(self, s: S) -> SignerMiddleware<Self, S>
       where S: Signer { ... }
    fn nonce_manager(self, address: Address) -> NonceManagerMiddleware<Self> { ... }
    fn gas_oracle<G>(self, gas_oracle: G) -> GasOracleMiddleware<Self, G>
       where G: GasOracle { ... }
}

Expand description

A builder trait to compose different Middleware layers and then build a composed Provider architecture.

Middleware composition acts in a wrapping fashion. Adding a new layer results in wrapping its predecessor.

use ethers_providers::{Middleware, Provider, Http};
use std::sync::Arc;
use std::convert::TryFrom;
use ethers_signers::{LocalWallet, Signer};
use ethers_middleware::{*, gas_escalator::*, gas_oracle::*};

fn builder_example() {
    let key = "fdb33e2105f08abe41a8ee3b758726a31abdd57b7a443f470f23efce853af169";
    let signer = key.parse::<LocalWallet>().unwrap();
    let address = signer.address();
    let escalator = GeometricGasPrice::new(1.125, 60_u64, None::<u64>);
    let gas_oracle = GasNow::new();

    let provider = Provider::<Http>::try_from("http://localhost:8545")
        .unwrap()
        .wrap_into(|p| GasEscalatorMiddleware::new(p, escalator, Frequency::PerBlock))
        .gas_oracle(gas_oracle)
        .with_signer(signer)
        .nonce_manager(address); // Outermost layer
}

fn builder_example_raw_wrap() {
    let key = "fdb33e2105f08abe41a8ee3b758726a31abdd57b7a443f470f23efce853af169";
    let signer = key.parse::<LocalWallet>().unwrap();
    let address = signer.address();
    let escalator = GeometricGasPrice::new(1.125, 60_u64, None::<u64>);

    let provider = Provider::<Http>::try_from("http://localhost:8545")
        .unwrap()
        .wrap_into(|p| GasEscalatorMiddleware::new(p, escalator, Frequency::PerBlock))
        .wrap_into(|p| SignerMiddleware::new(p, signer))
        .wrap_into(|p| GasOracleMiddleware::new(p, GasNow::new()))
        .wrap_into(|p| NonceManagerMiddleware::new(p, address)); // Outermost layer
}