88 lines
2.6 KiB
Rust
88 lines
2.6 KiB
Rust
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 serde_aux::prelude::*;
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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 ETHERSCAN_URL_PREFIX: &str =
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"https://api.etherscan.io/api?module=gastracker&action=gasoracle";
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/// A client over HTTP for the [Etherscan](https://api.etherscan.io/api?module=gastracker&action=gasoracle) gas tracker API
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/// that implements the `GasOracle` trait
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#[derive(Debug)]
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pub struct Etherscan {
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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 EtherscanResponse {
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result: EtherscanResponseInner,
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}
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#[derive(Deserialize)]
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struct EtherscanResponseInner {
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#[serde(deserialize_with = "deserialize_number_from_string")]
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#[serde(rename = "SafeGasPrice")]
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safe_gas_price: u64,
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#[serde(deserialize_with = "deserialize_number_from_string")]
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#[serde(rename = "ProposeGasPrice")]
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propose_gas_price: u64,
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#[serde(deserialize_with = "deserialize_number_from_string")]
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#[serde(rename = "FastGasPrice")]
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fast_gas_price: u64,
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}
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impl Etherscan {
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/// Creates a new [Etherscan](https://etherscan.io/gastracker) gas price oracle.
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pub fn new(api_key: Option<&str>) -> Self {
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let url = match api_key {
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Some(key) => format!("{}&apikey={}", ETHERSCAN_URL_PREFIX, key),
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None => ETHERSCAN_URL_PREFIX.to_string(),
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};
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let url = Url::parse(&url).expect("invalid url");
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Etherscan {
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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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/// Sets the gas price category to be used when fetching the gas price.
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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 Etherscan {
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async fn fetch(&self) -> Result<U256, GasOracleError> {
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if matches!(self.gas_category, GasCategory::Fastest) {
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return Err(GasOracleError::GasCategoryNotSupported);
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}
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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::<EtherscanResponse>()
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.await?;
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match self.gas_category {
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GasCategory::SafeLow => Ok(U256::from(res.result.safe_gas_price * GWEI_TO_WEI)),
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GasCategory::Standard => Ok(U256::from(res.result.propose_gas_price * GWEI_TO_WEI)),
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GasCategory::Fast => Ok(U256::from(res.result.fast_gas_price * GWEI_TO_WEI)),
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_ => Err(GasOracleError::GasCategoryNotSupported),
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}
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}
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}
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