73 lines
2.0 KiB
Rust
73 lines
2.0 KiB
Rust
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use ethers_core::types::U256;
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use async_trait::async_trait;
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use reqwest::Client;
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use serde::Deserialize;
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use url::Url;
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use crate::gas_oracle::{GasCategory, GasOracle, GasOracleError, GWEI_TO_WEI};
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const ETH_GAS_STATION_URL_PREFIX: &str = "https://ethgasstation.info/api/ethgasAPI.json";
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/// A client over HTTP for the [EthGasStation](https://ethgasstation.info/api/ethgasAPI.json) gas tracker API
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/// that implements the `GasOracle` trait
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#[derive(Debug)]
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pub struct EthGasStation {
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client: Client,
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url: Url,
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gas_category: GasCategory,
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}
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#[derive(Deserialize)]
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struct EthGasStationResponse {
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#[serde(rename = "safeLow")]
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safe_low: u64,
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average: u64,
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fast: u64,
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fastest: u64,
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}
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impl EthGasStation {
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pub fn new(api_key: Option<&'static str>) -> Self {
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let url = match api_key {
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Some(key) => format!("{}?api-key={}", ETH_GAS_STATION_URL_PREFIX, key),
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None => ETH_GAS_STATION_URL_PREFIX.to_string(),
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};
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let url = Url::parse(&url).expect("invalid url");
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EthGasStation {
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client: Client::new(),
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url,
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gas_category: GasCategory::Standard,
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}
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}
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pub fn category(mut self, gas_category: GasCategory) -> Self {
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self.gas_category = gas_category;
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self
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}
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}
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#[async_trait]
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impl GasOracle for EthGasStation {
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async fn fetch(&self) -> Result<U256, GasOracleError> {
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let res = self
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.client
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.get(self.url.as_ref())
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.send()
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.await?
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.json::<EthGasStationResponse>()
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.await?;
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let gas_price = match self.gas_category {
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GasCategory::SafeLow => U256::from((res.safe_low * GWEI_TO_WEI) / 10),
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GasCategory::Standard => U256::from((res.average * GWEI_TO_WEI) / 10),
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GasCategory::Fast => U256::from((res.fast * GWEI_TO_WEI) / 10),
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GasCategory::Fastest => U256::from((res.fastest * GWEI_TO_WEI) / 10),
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};
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Ok(gas_price)
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}
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}
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