Add --forward-call for eth_call and eth_estimateGas

bin/reth/Cargo.toml

@@ -72,6 +72,7 @@ alloy-rlp.workspace = true
 alloy-rpc-types = { workspace = true, features = ["engine"] }
 alloy-consensus.workspace = true
 alloy-primitives.workspace = true
+alloy-rpc-types-eth.workspace = true
 
 # tracing
 tracing.workspace = true

bin/reth/src/call_forwarder.rs

@@ -0,0 +1,97 @@
+use alloy_eips::BlockId;
+use alloy_primitives::{Bytes, U256};
+use alloy_rpc_types_eth::{state::StateOverride, transaction::TransactionRequest, BlockOverrides};
+use jsonrpsee::{
+    http_client::{HttpClient, HttpClientBuilder},
+    proc_macros::rpc,
+    rpc_params,
+    types::{error::INTERNAL_ERROR_CODE, ErrorObject},
+};
+use jsonrpsee_core::{async_trait, client::ClientT, ClientError, RpcResult};
+
+#[rpc(server, namespace = "eth")]
+pub(crate) trait CallForwarderApi {
+    /// Executes a new message call immediately without creating a transaction on the block chain.
+    #[method(name = "call")]
+    async fn call(
+        &self,
+        request: TransactionRequest,
+        block_number: Option<BlockId>,
+        state_overrides: Option<StateOverride>,
+        block_overrides: Option<Box<BlockOverrides>>,
+    ) -> RpcResult<Bytes>;
+
+    /// Generates and returns an estimate of how much gas is necessary to allow the transaction to
+    /// complete.
+    #[method(name = "estimateGas")]
+    async fn estimate_gas(
+        &self,
+        request: TransactionRequest,
+        block_number: Option<BlockId>,
+        state_override: Option<StateOverride>,
+    ) -> RpcResult<U256>;
+}
+
+pub(crate) struct CallForwarderExt {
+    client: HttpClient,
+}
+
+impl CallForwarderExt {
+    pub(crate) fn new(upstream_rpc_url: String) -> Self {
+        let client =
+            HttpClientBuilder::default().build(upstream_rpc_url).expect("Failed to build client");
+
+        Self { client }
+    }
+}
+
+#[async_trait]
+impl CallForwarderApiServer for CallForwarderExt {
+    async fn call(
+        &self,
+        request: TransactionRequest,
+        block_number: Option<BlockId>,
+        state_overrides: Option<StateOverride>,
+        block_overrides: Option<Box<BlockOverrides>>,
+    ) -> RpcResult<Bytes> {
+        let result = self
+            .client
+            .clone()
+            .request(
+                "eth_call",
+                rpc_params![request, block_number, state_overrides, block_overrides],
+            )
+            .await
+            .map_err(|e| match e {
+                ClientError::Call(e) => e,
+                _ => ErrorObject::owned(
+                    INTERNAL_ERROR_CODE,
+                    format!("Failed to call: {:?}", e),
+                    Some(()),
+                ),
+            })?;
+        Ok(result)
+    }
+
+    async fn estimate_gas(
+        &self,
+        request: TransactionRequest,
+        block_number: Option<BlockId>,
+        state_override: Option<StateOverride>,
+    ) -> RpcResult<U256> {
+        let result = self
+            .client
+            .clone()
+            .request("eth_estimateGas", rpc_params![request, block_number, state_override])
+            .await
+            .map_err(|e| match e {
+                ClientError::Call(e) => e,
+                _ => ErrorObject::owned(
+                    INTERNAL_ERROR_CODE,
+                    format!("Failed to estimate gas: {:?}", e),
+                    Some(()),
+                ),
+            })?;
+        Ok(result)
+    }
+}

bin/reth/src/main.rs

@@ -4,23 +4,29 @@
 static ALLOC: reth_cli_util::allocator::Allocator = reth_cli_util::allocator::new_allocator();
 
 mod block_ingest;
-mod forwarder;
+mod call_forwarder;
 mod serialized;
 mod spot_meta;
+mod tx_forwarder;
 
 use block_ingest::BlockIngest;
+use call_forwarder::CallForwarderApiServer;
 use clap::{Args, Parser};
-use forwarder::EthForwarderApiServer;
 use reth::cli::Cli;
 use reth_ethereum_cli::chainspec::EthereumChainSpecParser;
 use reth_node_ethereum::EthereumNode;
 use tracing::info;
+use tx_forwarder::EthForwarderApiServer;
 
 #[derive(Args, Debug, Clone)]
 struct HyperliquidExtArgs {
     /// Upstream RPC URL to forward incoming transactions.
     #[arg(long, default_value = "https://rpc.hyperliquid.xyz/evm")]
     pub upstream_rpc_url: String,
+
+    /// Forward eth_call and eth_estimateGas to the upstream RPC.
+    #[arg(long)]
+    pub forward_call: bool,
 }
 
 fn main() {
@@ -38,12 +44,17 @@ fn main() {
             let handle = builder
                 .node(EthereumNode::default())
                 .extend_rpc_modules(move |ctx| {
-                    let upstream_rpc_url = ext_args.upstream_rpc_url.clone();
-                    let rpc = forwarder::EthForwarderExt::new(upstream_rpc_url).into_rpc();
-                    for method_name in rpc.method_names() {
-                        ctx.modules.remove_method_from_configured(method_name);
+                    let upstream_rpc_url = ext_args.upstream_rpc_url;
+                    ctx.modules.replace_configured(
+                        tx_forwarder::EthForwarderExt::new(upstream_rpc_url.clone()).into_rpc(),
+                    )?;
+
+                    if ext_args.forward_call {
+                        ctx.modules.replace_configured(
+                            call_forwarder::CallForwarderExt::new(upstream_rpc_url.clone())
+                                .into_rpc(),
+                        )?;
                     }
-                    ctx.modules.merge_configured(rpc)?;
 
                     info!("Transaction forwarder extension enabled");
                     Ok(())