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

88 lines
2.6 KiB
Rust

use super::{from_gwei_f64, GasCategory, GasOracle, GasOracleError, Result};
use async_trait::async_trait;
use ethers_core::types::U256;
use reqwest::Client;
use serde::Deserialize;
use url::Url;
const 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)]
#[must_use]
pub struct Etherchain {
client: Client,
url: Url,
gas_category: GasCategory,
}
#[derive(Clone, Copy, Debug, Deserialize, PartialEq)]
#[serde(rename_all = "camelCase")]
pub struct Response {
pub safe_low: f64,
pub standard: f64,
pub fast: f64,
pub fastest: f64,
pub current_base_fee: f64,
pub recommended_base_fee: f64,
}
impl Response {
#[inline]
pub fn gas_from_category(&self, gas_category: GasCategory) -> f64 {
match gas_category {
GasCategory::SafeLow => self.safe_low,
GasCategory::Standard => self.standard,
GasCategory::Fast => self.fast,
GasCategory::Fastest => self.fastest,
}
}
}
impl Default for Etherchain {
fn default() -> Self {
Self::new()
}
}
#[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> {
let res = self.query().await?;
let gas_price = res.gas_from_category(self.gas_category);
Ok(from_gwei_f64(gas_price))
}
async fn estimate_eip1559_fees(&self) -> Result<(U256, U256)> {
Err(GasOracleError::Eip1559EstimationNotSupported)
}
}
impl Etherchain {
/// Creates a new [Etherchain](https://etherchain.org/tools/gasPriceOracle) gas price oracle.
pub fn new() -> Self {
Self::with_client(Client::new())
}
/// Same as [`Self::new`] but with a custom [`Client`].
pub fn with_client(client: Client) -> Self {
let url = Url::parse(URL).unwrap();
Etherchain { client, 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
}
/// Perform a request to the gas price API and deserialize the response.
pub async fn query(&self) -> Result<Response> {
let response =
self.client.get(self.url.clone()).send().await?.error_for_status()?.json().await?;
Ok(response)
}
}