From 20aceb750c68fc6020f2ee884bafc0d745afe09e Mon Sep 17 00:00:00 2001
From: Roman Krasiuk <rokrassyuk@gmail.com>
Date: Tue, 21 Feb 2023 07:50:40 +0200
Subject: [PATCH] feat(engine-api): exchange capabilities (#1469)

Co-authored-by: Georgios Konstantopoulos <me@gakonst.com>
---
 crates/rpc/rpc-api/src/engine.rs       |  4 ++++
 crates/rpc/rpc-types/src/eth/engine.rs | 13 +++++++++++++
 crates/rpc/rpc/src/engine/mod.rs       |  7 ++++++-
 3 files changed, 23 insertions(+), 1 deletion(-)

diff --git a/crates/rpc/rpc-api/src/engine.rs b/crates/rpc/rpc-api/src/engine.rs
index c8fb3b642..bfe33742b 100644
--- a/crates/rpc/rpc-api/src/engine.rs
+++ b/crates/rpc/rpc-api/src/engine.rs
@@ -66,4 +66,8 @@ pub trait EngineApi {
         &self,
         transition_configuration: TransitionConfiguration,
     ) -> Result<TransitionConfiguration>;
+
+    /// See also <https://github.com/ethereum/execution-apis/blob/6452a6b194d7db269bf1dbd087a267251d3cc7f8/src/engine/common.md#capabilities>
+    #[method(name = "engine_exchangeCapabilities")]
+    async fn exchange_capabilities(&self, capabilities: Vec<String>) -> Result<Vec<String>>;
 }
diff --git a/crates/rpc/rpc-types/src/eth/engine.rs b/crates/rpc/rpc-types/src/eth/engine.rs
index 4d0d7667b..7ef76d02b 100644
--- a/crates/rpc/rpc-types/src/eth/engine.rs
+++ b/crates/rpc/rpc-types/src/eth/engine.rs
@@ -8,6 +8,19 @@ use reth_primitives::{
 use reth_rlp::Encodable;
 use serde::{Deserialize, Serialize};
 
+/// The list of supported Engine capabilities
+pub const CAPABILITIES: [&str; 9] = [
+    "engine_forkchoiceUpdatedV1",
+    "engine_forkchoiceUpdatedV2",
+    "engine_exchangeTransitionConfigurationV1",
+    "engine_getPayloadV1",
+    "engine_getPayloadV2",
+    "engine_newPayloadV1",
+    "engine_newPayloadV2",
+    "engine_getPayloadBodiesByHashV1",
+    "engine_getPayloadBodiesByRangeV1",
+];
+
 /// This structure maps on the ExecutionPayload structure of the beacon chain spec.
 ///
 /// See also: <https://github.com/ethereum/execution-apis/blob/6709c2a795b707202e93c4f2867fa0bf2640a84f/src/engine/paris.md#executionpayloadv1>
diff --git a/crates/rpc/rpc/src/engine/mod.rs b/crates/rpc/rpc/src/engine/mod.rs
index e7c492d96..677b658c4 100644
--- a/crates/rpc/rpc/src/engine/mod.rs
+++ b/crates/rpc/rpc/src/engine/mod.rs
@@ -13,7 +13,7 @@ use reth_rpc_engine_api::{
 };
 use reth_rpc_types::engine::{
     ExecutionPayload, ExecutionPayloadBodies, ForkchoiceUpdated, PayloadAttributes, PayloadStatus,
-    TransitionConfiguration,
+    TransitionConfiguration, CAPABILITIES,
 };
 use tokio::sync::{
     mpsc::UnboundedSender,
@@ -157,4 +157,9 @@ impl EngineApiServer for EngineApi {
         self.delegate_request(EngineApiMessage::ExchangeTransitionConfiguration(config, tx), rx)
             .await
     }
+
+    /// See also <https://github.com/ethereum/execution-apis/blob/6452a6b194d7db269bf1dbd087a267251d3cc7f8/src/engine/common.md#capabilities>
+    async fn exchange_capabilities(&self, _capabilities: Vec<String>) -> Result<Vec<String>> {
+        Ok(CAPABILITIES.into_iter().map(str::to_owned).collect())
+    }
 }