ethers-rs/ethers-middleware/src/gas_oracle/etherchain.rs

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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 {
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/// 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 }
}
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/// 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<EtherchainResponse, GasOracleError> {
Ok(self.client.get(self.url.as_ref()).send().await?.json::<EtherchainResponse>().await?)
}
}
#[cfg_attr(target_arch = "wasm32", async_trait(?Send))]
#[cfg_attr(not(target_arch = "wasm32"), async_trait)]
impl GasOracle for Etherchain {
async fn fetch(&self) -> Result<U256, GasOracleError> {
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)
}
}