feat: add comprehensive tests for StreamScannerHandler functionality

- Introduced a new test file for StreamScannerHandler, covering various scenarios including nil inputs, empty bodies, chunk processing, order preservation, and handler failures.
- Enhanced error handling and data processing logic in StreamScannerHandler to improve robustness and performance.

relay/helper/stream_scanner.go

@@ -176,10 +176,32 @@ func StreamScannerHandler(c *gin.Context, resp *http.Response, info *relaycommon
 		})
 	}
 
+	dataChan := make(chan string, 10)
+
+	wg.Add(1)
+	gopool.Go(func() {
+		defer func() {
+			wg.Done()
+			if r := recover(); r != nil {
+				logger.LogError(c, fmt.Sprintf("data handler goroutine panic: %v", r))
+			}
+			common.SafeSendBool(stopChan, true)
+		}()
+		for data := range dataChan {
+			writeMutex.Lock()
+			success := dataHandler(data)
+			writeMutex.Unlock()
+			if !success {
+				return
+			}
+		}
+	})
+
 	// Scanner goroutine with improved error handling
 	wg.Add(1)
 	common.RelayCtxGo(ctx, func() {
 		defer func() {
+			close(dataChan)
 			wg.Done()
 			if r := recover(); r != nil {
 				logger.LogError(c, fmt.Sprintf("scanner goroutine panic: %v", r))
@@ -222,22 +244,9 @@ func StreamScannerHandler(c *gin.Context, resp *http.Response, info *relaycommon
 			if !strings.HasPrefix(data, "[DONE]") {
 				info.SetFirstResponseTime()
 				info.ReceivedResponseCount++
-				// 使用超时机制防止写操作阻塞
-				done := make(chan bool, 1)
-				gopool.Go(func() {
-					writeMutex.Lock()
-					defer writeMutex.Unlock()
-					done <- dataHandler(data)
-				})
 
 				select {
-				case success := <-done:
-					if !success {
-						return
-					}
-				case <-time.After(10 * time.Second):
-					logger.LogError(c, "data handler timeout")
-					return
+				case dataChan <- data:
 				case <-ctx.Done():
 					return
 				case <-stopChan:

relay/helper/stream_scanner_test.go

@@ -0,0 +1,521 @@
+package helper
+
+import (
+	"fmt"
+	"io"
+	"net/http"
+	"net/http/httptest"
+	"strings"
+	"sync"
+	"sync/atomic"
+	"testing"
+	"time"
+
+	"github.com/QuantumNous/new-api/constant"
+	relaycommon "github.com/QuantumNous/new-api/relay/common"
+	"github.com/QuantumNous/new-api/setting/operation_setting"
+	"github.com/gin-gonic/gin"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+func init() {
+	gin.SetMode(gin.TestMode)
+}
+
+func setupStreamTest(t *testing.T, body io.Reader) (*gin.Context, *http.Response, *relaycommon.RelayInfo) {
+	t.Helper()
+
+	oldTimeout := constant.StreamingTimeout
+	constant.StreamingTimeout = 30
+	t.Cleanup(func() {
+		constant.StreamingTimeout = oldTimeout
+	})
+
+	recorder := httptest.NewRecorder()
+	c, _ := gin.CreateTestContext(recorder)
+	c.Request = httptest.NewRequest(http.MethodPost, "/v1/chat/completions", nil)
+
+	resp := &http.Response{
+		Body: io.NopCloser(body),
+	}
+
+	info := &relaycommon.RelayInfo{
+		ChannelMeta: &relaycommon.ChannelMeta{},
+	}
+
+	return c, resp, info
+}
+
+func buildSSEBody(n int) string {
+	var b strings.Builder
+	for i := 0; i < n; i++ {
+		fmt.Fprintf(&b, "data: {\"id\":%d,\"choices\":[{\"delta\":{\"content\":\"token_%d\"}}]}\n", i, i)
+	}
+	b.WriteString("data: [DONE]\n")
+	return b.String()
+}
+
+// slowReader wraps a reader and injects a delay before each Read call,
+// simulating a slow upstream that trickles data.
+type slowReader struct {
+	r     io.Reader
+	delay time.Duration
+}
+
+func (s *slowReader) Read(p []byte) (int, error) {
+	time.Sleep(s.delay)
+	return s.r.Read(p)
+}
+
+// ---------- Basic correctness ----------
+
+func TestStreamScannerHandler_NilInputs(t *testing.T) {
+	t.Parallel()
+
+	recorder := httptest.NewRecorder()
+	c, _ := gin.CreateTestContext(recorder)
+	c.Request = httptest.NewRequest(http.MethodPost, "/", nil)
+
+	info := &relaycommon.RelayInfo{ChannelMeta: &relaycommon.ChannelMeta{}}
+
+	StreamScannerHandler(c, nil, info, func(data string) bool { return true })
+	StreamScannerHandler(c, &http.Response{Body: io.NopCloser(strings.NewReader(""))}, info, nil)
+}
+
+func TestStreamScannerHandler_EmptyBody(t *testing.T) {
+	t.Parallel()
+
+	c, resp, info := setupStreamTest(t, strings.NewReader(""))
+
+	var called atomic.Bool
+	StreamScannerHandler(c, resp, info, func(data string) bool {
+		called.Store(true)
+		return true
+	})
+
+	assert.False(t, called.Load(), "handler should not be called for empty body")
+}
+
+func TestStreamScannerHandler_1000Chunks(t *testing.T) {
+	t.Parallel()
+
+	const numChunks = 1000
+	body := buildSSEBody(numChunks)
+	c, resp, info := setupStreamTest(t, strings.NewReader(body))
+
+	var count atomic.Int64
+	StreamScannerHandler(c, resp, info, func(data string) bool {
+		count.Add(1)
+		return true
+	})
+
+	assert.Equal(t, int64(numChunks), count.Load())
+	assert.Equal(t, numChunks, info.ReceivedResponseCount)
+}
+
+func TestStreamScannerHandler_10000Chunks(t *testing.T) {
+	t.Parallel()
+
+	const numChunks = 10000
+	body := buildSSEBody(numChunks)
+	c, resp, info := setupStreamTest(t, strings.NewReader(body))
+
+	var count atomic.Int64
+	start := time.Now()
+
+	StreamScannerHandler(c, resp, info, func(data string) bool {
+		count.Add(1)
+		return true
+	})
+
+	elapsed := time.Since(start)
+	assert.Equal(t, int64(numChunks), count.Load())
+	assert.Equal(t, numChunks, info.ReceivedResponseCount)
+	t.Logf("10000 chunks processed in %v", elapsed)
+}
+
+func TestStreamScannerHandler_OrderPreserved(t *testing.T) {
+	t.Parallel()
+
+	const numChunks = 500
+	body := buildSSEBody(numChunks)
+	c, resp, info := setupStreamTest(t, strings.NewReader(body))
+
+	var mu sync.Mutex
+	received := make([]string, 0, numChunks)
+
+	StreamScannerHandler(c, resp, info, func(data string) bool {
+		mu.Lock()
+		received = append(received, data)
+		mu.Unlock()
+		return true
+	})
+
+	require.Equal(t, numChunks, len(received))
+	for i := 0; i < numChunks; i++ {
+		expected := fmt.Sprintf("{\"id\":%d,\"choices\":[{\"delta\":{\"content\":\"token_%d\"}}]}", i, i)
+		assert.Equal(t, expected, received[i], "chunk %d out of order", i)
+	}
+}
+
+func TestStreamScannerHandler_DoneStopsScanner(t *testing.T) {
+	t.Parallel()
+
+	body := buildSSEBody(50) + "data: should_not_appear\n"
+	c, resp, info := setupStreamTest(t, strings.NewReader(body))
+
+	var count atomic.Int64
+	StreamScannerHandler(c, resp, info, func(data string) bool {
+		count.Add(1)
+		return true
+	})
+
+	assert.Equal(t, int64(50), count.Load(), "data after [DONE] must not be processed")
+}
+
+func TestStreamScannerHandler_HandlerFailureStops(t *testing.T) {
+	t.Parallel()
+
+	const numChunks = 200
+	body := buildSSEBody(numChunks)
+	c, resp, info := setupStreamTest(t, strings.NewReader(body))
+
+	const failAt = 50
+	var count atomic.Int64
+	StreamScannerHandler(c, resp, info, func(data string) bool {
+		n := count.Add(1)
+		return n < failAt
+	})
+
+	// The worker stops at failAt; the scanner may have read ahead,
+	// but the handler should not be called beyond failAt.
+	assert.Equal(t, int64(failAt), count.Load())
+}
+
+func TestStreamScannerHandler_SkipsNonDataLines(t *testing.T) {
+	t.Parallel()
+
+	var b strings.Builder
+	b.WriteString(": comment line\n")
+	b.WriteString("event: message\n")
+	b.WriteString("id: 12345\n")
+	b.WriteString("retry: 5000\n")
+	for i := 0; i < 100; i++ {
+		fmt.Fprintf(&b, "data: payload_%d\n", i)
+		b.WriteString(": interleaved comment\n")
+	}
+	b.WriteString("data: [DONE]\n")
+
+	c, resp, info := setupStreamTest(t, strings.NewReader(b.String()))
+
+	var count atomic.Int64
+	StreamScannerHandler(c, resp, info, func(data string) bool {
+		count.Add(1)
+		return true
+	})
+
+	assert.Equal(t, int64(100), count.Load())
+}
+
+func TestStreamScannerHandler_DataWithExtraSpaces(t *testing.T) {
+	t.Parallel()
+
+	body := "data:   {\"trimmed\":true}  \ndata: [DONE]\n"
+	c, resp, info := setupStreamTest(t, strings.NewReader(body))
+
+	var got string
+	StreamScannerHandler(c, resp, info, func(data string) bool {
+		got = data
+		return true
+	})
+
+	assert.Equal(t, "{\"trimmed\":true}", got)
+}
+
+// ---------- Decoupling: scanner not blocked by slow handler ----------
+
+func TestStreamScannerHandler_ScannerDecoupledFromSlowHandler(t *testing.T) {
+	t.Parallel()
+
+	// Strategy: use a slow upstream (io.Pipe, 10ms per chunk) AND a slow handler (20ms per chunk).
+	// If the scanner were synchronously coupled to the handler, total time would be
+	// ~numChunks * (10ms + 20ms) = 30ms * 50 = 1500ms.
+	// With decoupling, total time should be closer to
+	// ~numChunks * max(10ms, 20ms) = 20ms * 50 = 1000ms
+	// because the scanner reads ahead into the buffer while the handler processes.
+	const numChunks = 50
+	const upstreamDelay = 10 * time.Millisecond
+	const handlerDelay = 20 * time.Millisecond
+
+	pr, pw := io.Pipe()
+	go func() {
+		defer pw.Close()
+		for i := 0; i < numChunks; i++ {
+			fmt.Fprintf(pw, "data: {\"id\":%d}\n", i)
+			time.Sleep(upstreamDelay)
+		}
+		fmt.Fprint(pw, "data: [DONE]\n")
+	}()
+
+	recorder := httptest.NewRecorder()
+	c, _ := gin.CreateTestContext(recorder)
+	c.Request = httptest.NewRequest(http.MethodPost, "/v1/chat/completions", nil)
+
+	oldTimeout := constant.StreamingTimeout
+	constant.StreamingTimeout = 30
+	t.Cleanup(func() { constant.StreamingTimeout = oldTimeout })
+
+	resp := &http.Response{Body: pr}
+	info := &relaycommon.RelayInfo{ChannelMeta: &relaycommon.ChannelMeta{}}
+
+	var count atomic.Int64
+	start := time.Now()
+	done := make(chan struct{})
+	go func() {
+		StreamScannerHandler(c, resp, info, func(data string) bool {
+			time.Sleep(handlerDelay)
+			count.Add(1)
+			return true
+		})
+		close(done)
+	}()
+
+	select {
+	case <-done:
+	case <-time.After(15 * time.Second):
+		t.Fatal("StreamScannerHandler did not complete in time")
+	}
+
+	elapsed := time.Since(start)
+	assert.Equal(t, int64(numChunks), count.Load())
+
+	coupledTime := time.Duration(numChunks) * (upstreamDelay + handlerDelay)
+	t.Logf("elapsed=%v, coupled_estimate=%v", elapsed, coupledTime)
+
+	// If decoupled, elapsed should be well under the coupled estimate.
+	assert.Less(t, elapsed, coupledTime*85/100,
+		"decoupled elapsed time (%v) should be significantly less than coupled estimate (%v)", elapsed, coupledTime)
+}
+
+func TestStreamScannerHandler_SlowUpstreamFastHandler(t *testing.T) {
+	t.Parallel()
+
+	const numChunks = 50
+	body := buildSSEBody(numChunks)
+	reader := &slowReader{r: strings.NewReader(body), delay: 2 * time.Millisecond}
+	c, resp, info := setupStreamTest(t, reader)
+
+	var count atomic.Int64
+	start := time.Now()
+
+	done := make(chan struct{})
+	go func() {
+		StreamScannerHandler(c, resp, info, func(data string) bool {
+			count.Add(1)
+			return true
+		})
+		close(done)
+	}()
+
+	select {
+	case <-done:
+	case <-time.After(15 * time.Second):
+		t.Fatal("timed out with slow upstream")
+	}
+
+	elapsed := time.Since(start)
+	assert.Equal(t, int64(numChunks), count.Load())
+	t.Logf("slow upstream (%d chunks, 2ms/read): %v", numChunks, elapsed)
+}
+
+// ---------- Ping tests ----------
+
+func TestStreamScannerHandler_PingSentDuringSlowUpstream(t *testing.T) {
+	t.Parallel()
+
+	setting := operation_setting.GetGeneralSetting()
+	oldEnabled := setting.PingIntervalEnabled
+	oldSeconds := setting.PingIntervalSeconds
+	setting.PingIntervalEnabled = true
+	setting.PingIntervalSeconds = 1
+	t.Cleanup(func() {
+		setting.PingIntervalEnabled = oldEnabled
+		setting.PingIntervalSeconds = oldSeconds
+	})
+
+	// Create a reader that delivers data slowly: one chunk every 500ms over 3.5 seconds.
+	// The ping interval is 1s, so we should see at least 2 pings.
+	pr, pw := io.Pipe()
+	go func() {
+		defer pw.Close()
+		for i := 0; i < 7; i++ {
+			fmt.Fprintf(pw, "data: chunk_%d\n", i)
+			time.Sleep(500 * time.Millisecond)
+		}
+		fmt.Fprint(pw, "data: [DONE]\n")
+	}()
+
+	recorder := httptest.NewRecorder()
+	c, _ := gin.CreateTestContext(recorder)
+	c.Request = httptest.NewRequest(http.MethodPost, "/v1/chat/completions", nil)
+
+	oldTimeout := constant.StreamingTimeout
+	constant.StreamingTimeout = 30
+	t.Cleanup(func() {
+		constant.StreamingTimeout = oldTimeout
+	})
+
+	resp := &http.Response{Body: pr}
+	info := &relaycommon.RelayInfo{ChannelMeta: &relaycommon.ChannelMeta{}}
+
+	var count atomic.Int64
+	done := make(chan struct{})
+	go func() {
+		StreamScannerHandler(c, resp, info, func(data string) bool {
+			count.Add(1)
+			return true
+		})
+		close(done)
+	}()
+
+	select {
+	case <-done:
+	case <-time.After(15 * time.Second):
+		t.Fatal("timed out waiting for stream to finish")
+	}
+
+	assert.Equal(t, int64(7), count.Load())
+
+	body := recorder.Body.String()
+	pingCount := strings.Count(body, ": PING")
+	t.Logf("received %d pings in response body", pingCount)
+	assert.GreaterOrEqual(t, pingCount, 2,
+		"expected at least 2 pings during 3.5s stream with 1s interval; got %d", pingCount)
+}
+
+func TestStreamScannerHandler_PingDisabledByRelayInfo(t *testing.T) {
+	t.Parallel()
+
+	setting := operation_setting.GetGeneralSetting()
+	oldEnabled := setting.PingIntervalEnabled
+	oldSeconds := setting.PingIntervalSeconds
+	setting.PingIntervalEnabled = true
+	setting.PingIntervalSeconds = 1
+	t.Cleanup(func() {
+		setting.PingIntervalEnabled = oldEnabled
+		setting.PingIntervalSeconds = oldSeconds
+	})
+
+	pr, pw := io.Pipe()
+	go func() {
+		defer pw.Close()
+		for i := 0; i < 5; i++ {
+			fmt.Fprintf(pw, "data: chunk_%d\n", i)
+			time.Sleep(500 * time.Millisecond)
+		}
+		fmt.Fprint(pw, "data: [DONE]\n")
+	}()
+
+	recorder := httptest.NewRecorder()
+	c, _ := gin.CreateTestContext(recorder)
+	c.Request = httptest.NewRequest(http.MethodPost, "/v1/chat/completions", nil)
+
+	oldTimeout := constant.StreamingTimeout
+	constant.StreamingTimeout = 30
+	t.Cleanup(func() {
+		constant.StreamingTimeout = oldTimeout
+	})
+
+	resp := &http.Response{Body: pr}
+	info := &relaycommon.RelayInfo{
+		DisablePing: true,
+		ChannelMeta: &relaycommon.ChannelMeta{},
+	}
+
+	var count atomic.Int64
+	done := make(chan struct{})
+	go func() {
+		StreamScannerHandler(c, resp, info, func(data string) bool {
+			count.Add(1)
+			return true
+		})
+		close(done)
+	}()
+
+	select {
+	case <-done:
+	case <-time.After(15 * time.Second):
+		t.Fatal("timed out")
+	}
+
+	assert.Equal(t, int64(5), count.Load())
+
+	body := recorder.Body.String()
+	pingCount := strings.Count(body, ": PING")
+	assert.Equal(t, 0, pingCount, "pings should be disabled when DisablePing=true")
+}
+
+func TestStreamScannerHandler_PingInterleavesWithSlowUpstream(t *testing.T) {
+	t.Parallel()
+
+	setting := operation_setting.GetGeneralSetting()
+	oldEnabled := setting.PingIntervalEnabled
+	oldSeconds := setting.PingIntervalSeconds
+	setting.PingIntervalEnabled = true
+	setting.PingIntervalSeconds = 1
+	t.Cleanup(func() {
+		setting.PingIntervalEnabled = oldEnabled
+		setting.PingIntervalSeconds = oldSeconds
+	})
+
+	// Slow upstream + slow handler. Total stream takes ~5 seconds.
+	// The ping goroutine stays alive as long as the scanner is reading,
+	// so pings should fire between data writes.
+	pr, pw := io.Pipe()
+	go func() {
+		defer pw.Close()
+		for i := 0; i < 10; i++ {
+			fmt.Fprintf(pw, "data: chunk_%d\n", i)
+			time.Sleep(500 * time.Millisecond)
+		}
+		fmt.Fprint(pw, "data: [DONE]\n")
+	}()
+
+	recorder := httptest.NewRecorder()
+	c, _ := gin.CreateTestContext(recorder)
+	c.Request = httptest.NewRequest(http.MethodPost, "/v1/chat/completions", nil)
+
+	oldTimeout := constant.StreamingTimeout
+	constant.StreamingTimeout = 30
+	t.Cleanup(func() {
+		constant.StreamingTimeout = oldTimeout
+	})
+
+	resp := &http.Response{Body: pr}
+	info := &relaycommon.RelayInfo{ChannelMeta: &relaycommon.ChannelMeta{}}
+
+	var count atomic.Int64
+	done := make(chan struct{})
+	go func() {
+		StreamScannerHandler(c, resp, info, func(data string) bool {
+			count.Add(1)
+			return true
+		})
+		close(done)
+	}()
+
+	select {
+	case <-done:
+	case <-time.After(15 * time.Second):
+		t.Fatal("timed out")
+	}
+
+	assert.Equal(t, int64(10), count.Load())
+
+	body := recorder.Body.String()
+	pingCount := strings.Count(body, ": PING")
+	t.Logf("received %d pings interleaved with 10 chunks over 5s", pingCount)
+	assert.GreaterOrEqual(t, pingCount, 3,
+		"expected at least 3 pings during 5s stream with 1s ping interval; got %d", pingCount)
+}