fix(websocket): avoid panic on missing ethereum specific data

server/websocket.go

@@ -1037,6 +1037,14 @@ func setConfirmedBlockTxMetadata(tx *bchain.Tx, blockTime int64) {
 	}
 }
 
+func getEthereumInternalTransfers(tx *bchain.Tx) []bchain.EthereumInternalTransfer {
+	esd, ok := tx.CoinSpecificData.(bchain.EthereumSpecificData)
+	if !ok || esd.InternalData == nil {
+		return nil
+	}
+	return esd.InternalData.Transfers
+}
+
 func (s *WebsocketServer) publishNewBlockTxsByAddr(block *bchain.Block) {
 	for _, tx := range block.Txs {
 		setConfirmedBlockTxMetadata(&tx, block.Time)
@@ -1044,10 +1052,7 @@ func (s *WebsocketServer) publishNewBlockTxsByAddr(block *bchain.Block) {
 		var internalTransfers []bchain.EthereumInternalTransfer
 		if s.chainParser.GetChainType() == bchain.ChainEthereumType {
 			tokenTransfers, _ = s.chainParser.EthereumTypeGetTokenTransfersFromTx(&tx)
-			esd := tx.CoinSpecificData.(bchain.EthereumSpecificData)
-			if esd.InternalData != nil {
-				internalTransfers = esd.InternalData.Transfers
-			}
+			internalTransfers = getEthereumInternalTransfers(&tx)
 		}
 		vins := make([]bchain.MempoolVin, len(tx.Vin))
 		for i, vin := range tx.Vin {

server/websocket_test.go

@@ -47,3 +47,35 @@ func TestSetConfirmedBlockTxMetadataLeavesConfirmedTxUnchanged(t *testing.T) {
 		t.Fatalf("Time = %d, want 200", tx.Time)
 	}
 }
+
+func TestGetEthereumInternalTransfersMissingData(t *testing.T) {
+	tx := bchain.Tx{}
+
+	transfers := getEthereumInternalTransfers(&tx)
+
+	if len(transfers) != 0 {
+		t.Fatalf("len(transfers) = %d, want 0", len(transfers))
+	}
+}
+
+func TestGetEthereumInternalTransfersReturnsTransfers(t *testing.T) {
+	expected := []bchain.EthereumInternalTransfer{
+		{From: "0x111", To: "0x222"},
+	}
+	tx := bchain.Tx{
+		CoinSpecificData: bchain.EthereumSpecificData{
+			InternalData: &bchain.EthereumInternalData{
+				Transfers: expected,
+			},
+		},
+	}
+
+	transfers := getEthereumInternalTransfers(&tx)
+
+	if len(transfers) != len(expected) {
+		t.Fatalf("len(transfers) = %d, want %d", len(transfers), len(expected))
+	}
+	if transfers[0].From != expected[0].From || transfers[0].To != expected[0].To {
+		t.Fatalf("transfers[0] = %+v, want %+v", transfers[0], expected[0])
+	}
+}