use ethers_core::types::U256; use async_trait::async_trait; use reqwest::Client; use serde::Deserialize; use url::Url; use crate::gas_oracle::{GasCategory, GasOracle, GasOracleError, GWEI_TO_WEI}; const ETHERCHAIN_URL: &str = "https://www.etherchain.org/api/gasPriceOracle"; /// A client over HTTP for the [Etherchain](https://www.etherchain.org/api/gasPriceOracle) gas tracker API /// that implements the `GasOracle` trait #[derive(Clone, Debug)] pub struct Etherchain { client: Client, url: Url, gas_category: GasCategory, } impl Default for Etherchain { fn default() -> Self { Self::new() } } #[derive(Clone, Debug, Deserialize, PartialEq, PartialOrd)] #[serde(rename_all = "camelCase")] pub struct EtherchainResponse { pub safe_low: f32, pub standard: f32, pub fast: f32, pub fastest: f32, pub current_base_fee: f32, pub recommended_base_fee: f32, } impl Etherchain { /// Creates a new [Etherchain](https://etherchain.org/tools/gasPriceOracle) gas price oracle. pub fn new() -> Self { let url = Url::parse(ETHERCHAIN_URL).expect("invalid url"); Etherchain { client: Client::new(), url, gas_category: GasCategory::Standard, } } /// Sets the gas price category to be used when fetching the gas price. pub fn category(mut self, gas_category: GasCategory) -> Self { self.gas_category = gas_category; self } pub async fn query(&self) -> Result { Ok(self .client .get(self.url.as_ref()) .send() .await? .json::() .await?) } } #[async_trait] impl GasOracle for Etherchain { async fn fetch(&self) -> Result { let res = self.query().await?; let gas_price = match self.gas_category { GasCategory::SafeLow => U256::from((res.safe_low as u64) * GWEI_TO_WEI), GasCategory::Standard => U256::from((res.standard as u64) * GWEI_TO_WEI), GasCategory::Fast => U256::from((res.fast as u64) * GWEI_TO_WEI), GasCategory::Fastest => U256::from((res.fastest as u64) * GWEI_TO_WEI), }; Ok(gas_price) } async fn estimate_eip1559_fees(&self) -> Result<(U256, U256), GasOracleError> { Err(GasOracleError::Eip1559EstimationNotSupported) } }