From 03621f1ed9b5744b1a9eb45570948ded4a79d61b Mon Sep 17 00:00:00 2001
From: peakchao <zhangzhichaolove@vip.qq.com>
Date: Sat, 27 Jun 2026 18:59:02 +0800
Subject: [PATCH] fix(relay): remove extra blank line from Claude SSE stream

- stop appending a trailing newline to Claude stream data frames before CustomEvent writes the SSE terminator
- keep Claude native /v1/messages stream output at the standard single blank line between events
- add a regression test for consecutive Claude SSE chunks

Refs #5402
---
 relay/helper/common.go      |  2 +-
 relay/helper/common_test.go | 36 ++++++++++++++++++++++++++++++++++++
 2 files changed, 37 insertions(+), 1 deletion(-)
 create mode 100644 relay/helper/common_test.go

diff --git a/relay/helper/common.go b/relay/helper/common.go
index 17ce79d2a10..ae17a4e205a 100644
--- a/relay/helper/common.go
+++ b/relay/helper/common.go
@@ -68,7 +68,7 @@ func ClaudeData(c *gin.Context, resp dto.ClaudeResponse) error {
 
 func ClaudeChunkData(c *gin.Context, resp dto.ClaudeResponse, data string) {
 	c.Render(-1, common.CustomEvent{Data: fmt.Sprintf("event: %s\n", resp.Type)})
-	c.Render(-1, common.CustomEvent{Data: fmt.Sprintf("data: %s\n", data)})
+	c.Render(-1, common.CustomEvent{Data: fmt.Sprintf("data: %s", data)})
 	_ = FlushWriter(c)
 }
 
diff --git a/relay/helper/common_test.go b/relay/helper/common_test.go
new file mode 100644
index 00000000000..7411265fbec
--- /dev/null
+++ b/relay/helper/common_test.go
@@ -0,0 +1,36 @@
+package helper
+
+import (
+	"net/http"
+	"net/http/httptest"
+	"strings"
+	"testing"
+
+	"github.com/QuantumNous/new-api/dto"
+	"github.com/gin-gonic/gin"
+	"github.com/stretchr/testify/require"
+)
+
+func TestClaudeChunkDataDoesNotEmitExtraBlankLine(t *testing.T) {
+	oldMode := gin.Mode()
+	gin.SetMode(gin.TestMode)
+	t.Cleanup(func() { gin.SetMode(oldMode) })
+
+	recorder := httptest.NewRecorder()
+	c, _ := gin.CreateTestContext(recorder)
+	c.Request = httptest.NewRequest(http.MethodPost, "/v1/messages", nil)
+
+	ClaudeChunkData(c, dto.ClaudeResponse{Type: "message_start"}, `{"type":"message_start"}`)
+	ClaudeChunkData(c, dto.ClaudeResponse{Type: "content_block_start"}, `{"type":"content_block_start"}`)
+
+	require.Equal(t, strings.Join([]string{
+		`event: message_start`,
+		`data: {"type":"message_start"}`,
+		``,
+		`event: content_block_start`,
+		`data: {"type":"content_block_start"}`,
+		``,
+		``,
+	}, "\n"), recorder.Body.String())
+	require.NotContains(t, recorder.Body.String(), "\n\n\n")
+}