ethers-rs/examples/middleware/examples/policy.rs

40 lines
1.4 KiB
Rust

use ethers::{
core::{types::TransactionRequest, utils::Anvil},
middleware::{
policy::{PolicyMiddlewareError, RejectEverything},
MiddlewareBuilder, PolicyMiddleware,
},
providers::{Http, Middleware, Provider},
};
use eyre::Result;
/// Policy middleware is a way to inject custom logic into the process of sending transactions and
/// interacting with contracts on the Ethereum blockchain. It allows you to define rules or policies
/// that should be followed when performing these actions, and to customize the behavior of the
/// library based on these policies.
#[tokio::main]
async fn main() -> Result<()> {
let anvil = Anvil::new().spawn();
let endpoint = anvil.endpoint();
let provider = Provider::<Http>::try_from(endpoint)?;
let accounts = provider.get_accounts().await?;
let account = accounts[0];
let to = accounts[1];
let tx = TransactionRequest::new().from(account).to(to).value(1000);
let policy = RejectEverything;
let policy_middleware = provider.wrap_into(|p| PolicyMiddleware::new(p, policy));
match policy_middleware.send_transaction(tx, None).await {
Err(e) => {
// Given the RejectEverything policy, we expect to execute this branch
assert!(matches!(e, PolicyMiddlewareError::PolicyError(())))
}
_ => panic!("We don't expect this to happen!"),
}
Ok(())
}