From f8b9d9475e46a897c362f758aeeb5c780547be27 Mon Sep 17 00:00:00 2001
From: ramil <ramilexe@gmail.com>
Date: Tue, 20 Apr 2021 00:52:58 +0300
Subject: [PATCH] add eth_chainId JSON-RPC endpoint

---
 pkg/eth/api.go         | 13 +++++++++++++
 pkg/eth/backend.go     |  6 +++---
 pkg/graphql/graphql.go |  6 +++++-
 3 files changed, 21 insertions(+), 4 deletions(-)

diff --git a/pkg/eth/api.go b/pkg/eth/api.go
index 0b9f8e63..536673f3 100644
--- a/pkg/eth/api.go
+++ b/pkg/eth/api.go
@@ -167,6 +167,19 @@ func (pea *PublicEthAPI) GetBlockByHash(ctx context.Context, hash common.Hash, f
 	return nil, err
 }
 
+// ChainId is the EIP-155 replay-protection chain id for the current ethereum chain config.
+func (api *PublicEthAPI) ChainId() (hexutil.Uint64, error) {
+	chainID := new(big.Int)
+	block, err := api.B.CurrentBlock()
+	if err != nil {
+		return 0, err
+	}
+	if config := api.B.Config.ChainConfig; config.IsEIP155(block.Number()) {
+		chainID = config.ChainID
+	}
+	return (hexutil.Uint64)(chainID.Uint64()), nil
+}
+
 /*
 
 Uncles
diff --git a/pkg/eth/backend.go b/pkg/eth/backend.go
index 86474f7f..6d378fdd 100644
--- a/pkg/eth/backend.go
+++ b/pkg/eth/backend.go
@@ -202,9 +202,9 @@ func (b *Backend) GetTd(blockHash common.Hash) (*big.Int, error) {
 }
 
 // CurrentBlock returns the current block
-func (b *Backend) CurrentBlock() *types.Block {
-	block, _ := b.BlockByNumber(context.Background(), rpc.LatestBlockNumber)
-	return block
+func (b *Backend) CurrentBlock() (*types.Block, error) {
+	block, err := b.BlockByNumber(context.Background(), rpc.LatestBlockNumber)
+	return block, err
 }
 
 // BlockByNumberOrHash returns block by number or hash
diff --git a/pkg/graphql/graphql.go b/pkg/graphql/graphql.go
index a4f4a923..12533016 100644
--- a/pkg/graphql/graphql.go
+++ b/pkg/graphql/graphql.go
@@ -867,7 +867,11 @@ func (r *Resolver) Blocks(ctx context.Context, args struct {
 	if args.To != nil {
 		to = rpc.BlockNumber(*args.To)
 	} else {
-		to = rpc.BlockNumber(r.backend.CurrentBlock().Number().Int64())
+		block, err := r.backend.CurrentBlock()
+		if err != nil {
+			return []*Block{}, nil
+		}
+		to = rpc.BlockNumber(block.Number().Int64())
 	}
 	if to < from {
 		return []*Block{}, nil