From 97bc3611db7b4b60758c311e448d26514eb65ca8 Mon Sep 17 00:00:00 2001
From: Emilia Hane <elsaemiliaevahane@gmail.com>
Date: Wed, 26 Feb 2025 17:06:51 +0100
Subject: [PATCH] feat(engine): Op engine capabilities  (#14733)

Co-authored-by: Ishika Choudhury <117741714+Rimeeeeee@users.noreply.github.com>
Co-authored-by: Matthias Seitz <matthias.seitz@outlook.de>
---
 crates/node/builder/src/rpc.rs              | 16 ++++++++++++++--
 crates/optimism/node/src/rpc.rs             |  3 ++-
 crates/optimism/rpc/src/engine.rs           | 20 +++++++++++++++++++-
 crates/optimism/rpc/src/lib.rs              |  2 +-
 crates/rpc/rpc-engine-api/src/engine_api.rs |  7 ++++++-
 5 files changed, 42 insertions(+), 6 deletions(-)

diff --git a/crates/node/builder/src/rpc.rs b/crates/node/builder/src/rpc.rs
index 3824d3dad9..d4a5d66426 100644
--- a/crates/node/builder/src/rpc.rs
+++ b/crates/node/builder/src/rpc.rs
@@ -7,6 +7,7 @@ use std::{
 };
 
 use crate::{BeaconConsensusEngineEvent, BeaconConsensusEngineHandle, EthApiBuilderCtx};
+use alloy_primitives::map::HashSet;
 use alloy_rpc_types::engine::{ClientVersionV1, ExecutionData};
 use futures::TryFutureExt;
 use reth_chainspec::EthereumHardforks;
@@ -664,6 +665,17 @@ pub trait EngineApiBuilder<Node: FullNodeComponents>: Send + Sync {
 #[derive(Debug, Default)]
 pub struct BasicEngineApiBuilder<EV> {
     engine_validator_builder: EV,
+    capabilities: Option<EngineCapabilities>,
+}
+
+impl<EV> BasicEngineApiBuilder<EV> {
+    /// Sets list of capabilities supported by engine API. Takes list of method names.
+    pub fn capabilities(mut self, caps: &[&str]) -> Self {
+        self.capabilities = Some(EngineCapabilities::new(
+            caps.iter().map(|cap| cap.to_string()).collect::<HashSet<_>>(),
+        ));
+        self
+    }
 }
 
 impl<N, EV> EngineApiBuilder<N> for BasicEngineApiBuilder<EV>
@@ -685,7 +697,7 @@ where
     >;
 
     async fn build_engine_api(self, ctx: &AddOnsContext<'_, N>) -> eyre::Result<Self::EngineApi> {
-        let Self { engine_validator_builder } = self;
+        let Self { engine_validator_builder, capabilities } = self;
 
         let engine_validator = engine_validator_builder.build(ctx).await?;
         let client = ClientVersionV1 {
@@ -702,7 +714,7 @@ where
             ctx.node.pool().clone(),
             Box::new(ctx.node.task_executor().clone()),
             client,
-            EngineCapabilities::default(),
+            capabilities.unwrap_or_default(),
             engine_validator,
         ))
     }
diff --git a/crates/optimism/node/src/rpc.rs b/crates/optimism/node/src/rpc.rs
index 1da0d0dc15..cefed27fb9 100644
--- a/crates/optimism/node/src/rpc.rs
+++ b/crates/optimism/node/src/rpc.rs
@@ -1,5 +1,6 @@
 //! RPC component builder
 
+use reth_optimism_rpc::engine::OP_CAPABILITIES;
 pub use reth_optimism_rpc::OpEngineApi;
 
 use alloy_rpc_types_engine::ExecutionData;
@@ -34,7 +35,7 @@ where
     >;
 
     async fn build_engine_api(self, ctx: &AddOnsContext<'_, N>) -> eyre::Result<Self::EngineApi> {
-        let inner = self.inner.build_engine_api(ctx).await?;
+        let inner = self.inner.capabilities(OP_CAPABILITIES).build_engine_api(ctx).await?;
 
         Ok(OpEngineApi::new(inner))
     }
diff --git a/crates/optimism/rpc/src/engine.rs b/crates/optimism/rpc/src/engine.rs
index 52dba10eb2..69545827ff 100644
--- a/crates/optimism/rpc/src/engine.rs
+++ b/crates/optimism/rpc/src/engine.rs
@@ -17,6 +17,24 @@ use reth_rpc_api::IntoEngineApiRpcModule;
 use reth_rpc_engine_api::{EngineApi, EngineApiServer};
 use reth_transaction_pool::TransactionPool;
 
+/// The list of all supported Engine capabilities available over the engine endpoint.
+///
+/// Spec: <https://specs.optimism.io/protocol/exec-engine.html>
+pub const OP_CAPABILITIES: &[&str] = &[
+    "engine_forkchoiceUpdatedV2",
+    "engine_forkchoiceUpdatedV3",
+    "engine_exchangeTransitionConfigurationV1",
+    "engine_getClientVersionV1",
+    "engine_getPayloadV2",
+    "engine_getPayloadV3",
+    "engine_getPayloadV4",
+    "engine_newPayloadV2",
+    "engine_newPayloadV3",
+    "engine_newPayloadV4",
+    "engine_getPayloadBodiesByHashV1",
+    "engine_getPayloadBodiesByRangeV1",
+];
+
 /// Extension trait that gives access to Optimism engine API RPC methods.
 ///
 /// Note:
@@ -311,7 +329,7 @@ where
     }
 
     async fn exchange_capabilities(&self, _capabilities: Vec<String>) -> RpcResult<Vec<String>> {
-        EngineApiServer::exchange_capabilities(&self.inner, _capabilities).await
+        Ok(self.inner.capabilities().list())
     }
 }
 
diff --git a/crates/optimism/rpc/src/lib.rs b/crates/optimism/rpc/src/lib.rs
index b92e0c1064..d343e32d1a 100644
--- a/crates/optimism/rpc/src/lib.rs
+++ b/crates/optimism/rpc/src/lib.rs
@@ -17,7 +17,7 @@ pub mod witness;
 
 #[cfg(feature = "client")]
 pub use engine::OpEngineApiClient;
-pub use engine::{OpEngineApi, OpEngineApiServer};
+pub use engine::{OpEngineApi, OpEngineApiServer, OP_CAPABILITIES};
 pub use error::{OpEthApiError, OpInvalidTransactionError, SequencerClientError};
 pub use eth::{OpEthApi, OpReceiptBuilder};
 pub use sequencer::SequencerClient;
diff --git a/crates/rpc/rpc-engine-api/src/engine_api.rs b/crates/rpc/rpc-engine-api/src/engine_api.rs
index b7f3b03df9..37405a8d15 100644
--- a/crates/rpc/rpc-engine-api/src/engine_api.rs
+++ b/crates/rpc/rpc-engine-api/src/engine_api.rs
@@ -553,6 +553,11 @@ where
 
         Ok(self.inner.beacon_consensus.fork_choice_updated(state, payload_attrs, version).await?)
     }
+
+    /// Returns reference to supported capabilities.
+    pub fn capabilities(&self) -> &EngineCapabilities {
+        &self.inner.capabilities
+    }
 }
 
 impl<Provider, EngineT, Pool, Validator, ChainSpec>
@@ -1009,7 +1014,7 @@ where
     /// Handler for `engine_exchangeCapabilitiesV1`
     /// See also <https://github.com/ethereum/execution-apis/blob/6452a6b194d7db269bf1dbd087a267251d3cc7f8/src/engine/common.md#capabilities>
     async fn exchange_capabilities(&self, _capabilities: Vec<String>) -> RpcResult<Vec<String>> {
-        Ok(self.inner.capabilities.list())
+        Ok(self.capabilities().list())
     }
 
     async fn get_blobs_v1(