From bf44c9724f68d4aabc9ff1e27d278f36328b8d8f Mon Sep 17 00:00:00 2001
From: Ashutosh Varma <ashutoshvarma11@live.com>
Date: Wed, 13 Nov 2024 16:45:32 +0700
Subject: [PATCH] feat: add support for `eth_signTransaction` (#12500)

---
 crates/rpc/rpc-builder/tests/it/http.rs       | 14 ++++-----
 crates/rpc/rpc-eth-api/src/core.rs            |  5 ++--
 .../rpc-eth-api/src/helpers/transaction.rs    | 30 ++++++++++++-------
 3 files changed, 30 insertions(+), 19 deletions(-)

diff --git a/crates/rpc/rpc-builder/tests/it/http.rs b/crates/rpc/rpc-builder/tests/it/http.rs
index b5faa71cc..8393d9427 100644
--- a/crates/rpc/rpc-builder/tests/it/http.rs
+++ b/crates/rpc/rpc-builder/tests/it/http.rs
@@ -278,7 +278,13 @@ where
     .await
     .unwrap();
     EthApiClient::<Transaction, Block, Receipt>::syncing(client).await.unwrap();
-    EthApiClient::<Transaction, Block, Receipt>::send_transaction(client, transaction_request)
+    EthApiClient::<Transaction, Block, Receipt>::send_transaction(
+        client,
+        transaction_request.clone(),
+    )
+    .await
+    .unwrap_err();
+    EthApiClient::<Transaction, Block, Receipt>::sign_transaction(client, transaction_request)
         .await
         .unwrap_err();
     EthApiClient::<Transaction, Block, Receipt>::hashrate(client).await.unwrap();
@@ -318,12 +324,6 @@ where
         .err()
         .unwrap()
     ));
-    assert!(is_unimplemented(
-        EthApiClient::<Transaction, Block, Receipt>::sign_transaction(client, call_request.clone())
-            .await
-            .err()
-            .unwrap()
-    ));
 }
 
 async fn test_basic_debug_calls<C>(client: &C)
diff --git a/crates/rpc/rpc-eth-api/src/core.rs b/crates/rpc/rpc-eth-api/src/core.rs
index 8072021d9..9cd9ba292 100644
--- a/crates/rpc/rpc-eth-api/src/core.rs
+++ b/crates/rpc/rpc-eth-api/src/core.rs
@@ -780,8 +780,9 @@ where
     }
 
     /// Handler for: `eth_signTransaction`
-    async fn sign_transaction(&self, _transaction: TransactionRequest) -> RpcResult<Bytes> {
-        Err(internal_rpc_err("unimplemented"))
+    async fn sign_transaction(&self, request: TransactionRequest) -> RpcResult<Bytes> {
+        trace!(target: "rpc::eth", ?request, "Serving eth_signTransaction");
+        Ok(EthTransactions::sign_transaction(self, request).await?)
     }
 
     /// Handler for: `eth_signTypedData`
diff --git a/crates/rpc/rpc-eth-api/src/helpers/transaction.rs b/crates/rpc/rpc-eth-api/src/helpers/transaction.rs
index ca4b0322e..e041b8c46 100644
--- a/crates/rpc/rpc-eth-api/src/helpers/transaction.rs
+++ b/crates/rpc/rpc-eth-api/src/helpers/transaction.rs
@@ -400,16 +400,10 @@ pub trait EthTransactions: LoadTransaction<Provider: BlockReaderIdExt> {
         txn: TransactionRequest,
     ) -> impl Future<Output = Result<TransactionSigned, Self::Error>> + Send {
         async move {
-            let signers: Vec<_> = self.signers().read().iter().cloned().collect();
-            for signer in signers {
-                if signer.is_signer_for(from) {
-                    return match signer.sign_transaction(txn, from).await {
-                        Ok(tx) => Ok(tx),
-                        Err(e) => Err(e.into_eth_err()),
-                    }
-                }
-            }
-            Err(EthApiError::InvalidTransactionSignature.into())
+            self.find_signer(from)?
+                .sign_transaction(txn, from)
+                .await
+                .map_err(Self::Error::from_eth_err)
         }
     }
 
@@ -430,6 +424,22 @@ pub trait EthTransactions: LoadTransaction<Provider: BlockReaderIdExt> {
         }
     }
 
+    /// Signs a transaction request using the given account in request
+    /// Returns the EIP-2718 encoded signed transaction.
+    fn sign_transaction(
+        &self,
+        request: TransactionRequest,
+    ) -> impl Future<Output = Result<Bytes, Self::Error>> + Send {
+        async move {
+            let from = match request.from {
+                Some(from) => from,
+                None => return Err(SignError::NoAccount.into_eth_err()),
+            };
+
+            Ok(self.sign_request(&from, request).await?.encoded_2718().into())
+        }
+    }
+
     /// Encodes and signs the typed data according EIP-712. Payload must implement Eip712 trait.
     fn sign_typed_data(&self, data: &TypedData, account: Address) -> Result<Bytes, Self::Error> {
         Ok(self