web3-proxy/web3_proxy/src/response_cache.rs

use crate::{
    frontend::errors::Web3ProxyError, jsonrpc::JsonRpcErrorData, rpcs::blockchain::ArcBlock,
};
use derive_more::From;
use ethers::providers::ProviderError;
use hashbrown::hash_map::DefaultHashBuilder;
use quick_cache_ttl::{CacheWithTTL, Weighter};
use serde_json::value::RawValue;
use std::{
    borrow::Cow,
    hash::{Hash, Hasher},
    num::NonZeroU32,
};

#[derive(Clone, Debug, From, PartialEq, Eq)]
pub struct JsonRpcQueryCacheKey {
    pub from_block: Option<ArcBlock>,
    pub to_block: Option<ArcBlock>,
    pub method: String,
    pub params: Option<serde_json::Value>,
    pub cache_errors: bool,
}

impl Hash for JsonRpcQueryCacheKey {
    fn hash<H: Hasher>(&self, state: &mut H) {
        self.from_block.as_ref().map(|x| x.hash).hash(state);
        self.to_block.as_ref().map(|x| x.hash).hash(state);
        self.method.hash(state);

        // make sure preserve_order feature is OFF
        self.params.as_ref().map(|x| x.to_string()).hash(state);

        self.cache_errors.hash(state)
    }
}

pub type JsonRpcQueryCache = CacheWithTTL<
    JsonRpcQueryCacheKey,
    JsonRpcResponseData,
    JsonRpcQueryWeigher,
    DefaultHashBuilder,
>;

#[derive(Clone)]
pub struct JsonRpcQueryWeigher;

#[derive(Clone)]
pub enum JsonRpcResponseData {
    Result {
        value: Box<RawValue>,
        size: Option<NonZeroU32>,
    },
    Error {
        value: JsonRpcErrorData,
        size: Option<NonZeroU32>,
    },
}

impl JsonRpcResponseData {
    pub fn num_bytes(&self) -> NonZeroU32 {
        // TODO: dry this somehow
        match self {
            JsonRpcResponseData::Result { value, size } => size.unwrap_or_else(|| {
                let size = value.get().len();

                NonZeroU32::new(size.clamp(1, u32::MAX as usize) as u32).unwrap()
            }),
            JsonRpcResponseData::Error { value, size } => size.unwrap_or_else(|| {
                let size = serde_json::to_string(value).unwrap().len();

                NonZeroU32::new(size.clamp(1, u32::MAX as usize) as u32).unwrap()
            }),
        }
    }
}

impl From<serde_json::Value> for JsonRpcResponseData {
    fn from(value: serde_json::Value) -> Self {
        let value = RawValue::from_string(value.to_string()).unwrap();

        Self::Result { value, size: None }
    }
}

impl From<Box<RawValue>> for JsonRpcResponseData {
    fn from(value: Box<RawValue>) -> Self {
        Self::Result { value, size: None }
    }
}

impl From<JsonRpcErrorData> for JsonRpcResponseData {
    fn from(value: JsonRpcErrorData) -> Self {
        Self::Error { value, size: None }
    }
}

impl TryFrom<ProviderError> for JsonRpcErrorData {
    type Error = Web3ProxyError;

    fn try_from(e: ProviderError) -> Result<Self, Self::Error> {
        // TODO: move turning ClientError into json to a helper function?
        let code;
        let message: String;
        let data;

        match e {
            ProviderError::JsonRpcClientError(err) => {
                if let Some(err) = err.as_error_response() {
                    code = err.code;
                    message = err.message.clone();
                    data = err.data.clone();
                } else if let Some(err) = err.as_serde_error() {
                    // this is not an rpc error. keep it as an error
                    return Err(Web3ProxyError::BadResponse(format!(
                        "bad response: {}",
                        err
                    )));
                } else {
                    return Err(anyhow::anyhow!("unexpected ethers error! {:?}", err).into());
                }
            }
            e => return Err(e.into()),
        }

        Ok(JsonRpcErrorData {
            code,
            message: Cow::Owned(message),
            data,
        })
    }
}

impl Weighter<JsonRpcQueryCacheKey, (), JsonRpcResponseData> for JsonRpcQueryWeigher {
    fn weight(
        &self,
        _key: &JsonRpcQueryCacheKey,
        _qey: &(),
        value: &JsonRpcResponseData,
    ) -> NonZeroU32 {
        value.num_bytes()
    }
}