web3-proxy/web3_proxy/src/frontend/rpc_proxy_http.rs

//! Take a user's HTTP JSON-RPC requests and either respond from local data or proxy the request to a backend rpc server.

use super::authorization::{ip_is_authorized, key_is_authorized};
use super::errors::FrontendResult;
use crate::{app::Web3ProxyApp, jsonrpc::JsonRpcRequestEnum};
use axum::extract::Path;
use axum::headers::{Origin, Referer, UserAgent};
use axum::TypedHeader;
use axum::{response::IntoResponse, Extension, Json};
use axum_client_ip::ClientIp;
use axum_macros::debug_handler;
use itertools::Itertools;
use std::sync::Arc;

/// POST /rpc -- Public entrypoint for HTTP JSON-RPC requests. Web3 wallets use this.
/// Defaults to rate limiting by IP address, but can also read the Authorization header for a bearer token.
/// If possible, please use a WebSocket instead.
#[debug_handler]
pub async fn proxy_web3_rpc(
    Extension(app): Extension<Arc<Web3ProxyApp>>,
    ClientIp(ip): ClientIp,
    origin: Option<TypedHeader<Origin>>,
    Json(payload): Json<JsonRpcRequestEnum>,
) -> FrontendResult {
    // TODO: benchmark spawning this
    // TODO: do we care about keeping the TypedHeader wrapper?
    let origin = origin.map(|x| x.0);

    let (authorization, semaphore) = ip_is_authorized(&app, ip, origin).await?;

    let authorization = Arc::new(authorization);

    let (response, rpcs, _semaphore) = app
        .proxy_web3_rpc(authorization, payload)
        .await
        .map(|(x, y)| (x, y, semaphore))?;

    let mut response = Json(&response).into_response();

    let headers = response.headers_mut();

    // TODO: this might be slow. think about this more
    // TODO: special string if no rpcs were used (cache hit)?
    let rpcs: String = rpcs.into_iter().map(|x| x.name.clone()).join(",");

    headers.insert(
        "W3P-BACKEND-RPCS",
        rpcs.parse().expect("W3P-BACKEND-RPCS should always parse"),
    );

    Ok(response)
}

/// Authenticated entrypoint for HTTP JSON-RPC requests. Web3 wallets use this.
/// Rate limit and billing based on the api key in the url.
/// Can optionally authorized based on origin, referer, or user agent.
/// If possible, please use a WebSocket instead.
#[debug_handler]
pub async fn proxy_web3_rpc_with_key(
    Extension(app): Extension<Arc<Web3ProxyApp>>,
    ClientIp(ip): ClientIp,
    origin: Option<TypedHeader<Origin>>,
    referer: Option<TypedHeader<Referer>>,
    user_agent: Option<TypedHeader<UserAgent>>,
    Path(rpc_key): Path<String>,
    Json(payload): Json<JsonRpcRequestEnum>,
) -> FrontendResult {
    // TODO: DRY w/ proxy_web3_rpc
    // the request can take a while, so we spawn so that we can start serving another request
    let rpc_key = rpc_key.parse()?;

    let (authorization, semaphore) = key_is_authorized(
        &app,
        rpc_key,
        ip,
        origin.map(|x| x.0),
        referer.map(|x| x.0),
        user_agent.map(|x| x.0),
    )
    .await?;

    let authorization = Arc::new(authorization);

    let (response, rpcs, _semaphore) = app
        .proxy_web3_rpc(authorization, payload)
        .await
        .map(|(x, y)| (x, y, semaphore))?;

    let mut response = Json(&response).into_response();

    let headers = response.headers_mut();

    // TODO: special string if no rpcs were used (cache hit)? or is an empty string fine? maybe the rpc name + "cached"
    let rpcs: String = rpcs.into_iter().map(|x| x.name.clone()).join(",");

    headers.insert(
        "W3P-BACKEND-RPCs",
        rpcs.parse().expect("W3P-BACKEND-RPCS should always parse"),
    );

    Ok(response)
}