🐛 bug: Use Content-Length for bytesReceived and bytesSent tags in Logger Middleware (#3066)

* logger: Use Content-Length header for BytesReceived and BytesSent tags

* Use strconv.AppendInt instead of fasthttp.AppendUint

middleware/logger/default_logger.go

@@ -11,7 +11,6 @@ import (
 	"github.com/mattn/go-colorable"
 	"github.com/mattn/go-isatty"
 	"github.com/valyala/bytebufferpool"
-	"github.com/valyala/fasthttp"
 )
 
 // default logger for fiber
@@ -151,7 +150,7 @@ func beforeHandlerFunc(cfg Config) {
 
 func appendInt(output Buffer, v int) (int, error) {
 	old := output.Len()
-	output.Set(fasthttp.AppendUint(output.Bytes(), v))
+	output.Set(strconv.AppendInt(output.Bytes(), int64(v), 10))
 	return output.Len() - old, nil
 }
 

middleware/logger/logger_test.go

@@ -407,14 +407,40 @@ func Test_Response_Body(t *testing.T) {
 	require.Equal(t, expectedGetResponse, buf.String())
 
 	buf.Reset() // Reset buffer to test POST
-
 	_, err = app.Test(httptest.NewRequest(fiber.MethodPost, "/test", nil))
-	require.NoError(t, err)
 
 	expectedPostResponse := "Post in test"
+	require.NoError(t, err)
 	require.Equal(t, expectedPostResponse, buf.String())
 }
 
+// go test -run Test_Request_Body
+func Test_Request_Body(t *testing.T) {
+	t.Parallel()
+	buf := bytebufferpool.Get()
+	defer bytebufferpool.Put(buf)
+	app := fiber.New()
+
+	app.Use(New(Config{
+		Format: "${bytesReceived} ${bytesSent} ${status}",
+		Output: buf,
+	}))
+
+	app.Post("/", func(c fiber.Ctx) error {
+		c.Response().Header.SetContentLength(5)
+		return c.SendString("World")
+	})
+
+	// Create a POST request with a body
+	body := []byte("Hello")
+	req := httptest.NewRequest(fiber.MethodPost, "/", bytes.NewReader(body))
+	req.Header.Set("Content-Type", "application/octet-stream")
+
+	_, err := app.Test(req)
+	require.NoError(t, err)
+	require.Equal(t, "5 5 200", buf.String())
+}
+
 // go test -run Test_Logger_AppendUint
 func Test_Logger_AppendUint(t *testing.T) {
 	t.Parallel()
@@ -432,10 +458,21 @@ func Test_Logger_AppendUint(t *testing.T) {
 		return c.SendString("hello")
 	})
 
+	app.Get("/content", func(c fiber.Ctx) error {
+		c.Response().Header.SetContentLength(5)
+		return c.SendString("hello")
+	})
+
 	resp, err := app.Test(httptest.NewRequest(fiber.MethodGet, "/", nil))
 	require.NoError(t, err)
 	require.Equal(t, fiber.StatusOK, resp.StatusCode)
-	require.Equal(t, "0 5 200", buf.String())
+	require.Equal(t, "-2 0 200", buf.String())
+
+	buf.Reset()
+	resp, err = app.Test(httptest.NewRequest(fiber.MethodGet, "/content", nil))
+	require.NoError(t, err)
+	require.Equal(t, fiber.StatusOK, resp.StatusCode)
+	require.Equal(t, "-2 5 200", buf.String())
 }
 
 // go test -run Test_Logger_Data_Race -race
@@ -618,7 +655,9 @@ func Test_Logger_ByteSent_Streaming(t *testing.T) {
 	resp, err := app.Test(httptest.NewRequest(fiber.MethodGet, "/", nil))
 	require.NoError(t, err)
 	require.Equal(t, fiber.StatusOK, resp.StatusCode)
-	require.Equal(t, "0 0 200", buf.String())
+
+	// -2 means identity, -1 means chunked, 200 status
+	require.Equal(t, "-2 -1 200", buf.String())
 }
 
 type fakeOutput int

middleware/logger/tags.go

@@ -87,13 +87,10 @@ func createTagMap(cfg *Config) map[string]LogFunc {
 			return output.Write(c.Body())
 		},
 		TagBytesReceived: func(output Buffer, c fiber.Ctx, _ *Data, _ string) (int, error) {
-			return appendInt(output, len(c.Request().Body()))
+			return appendInt(output, c.Request().Header.ContentLength())
 		},
 		TagBytesSent: func(output Buffer, c fiber.Ctx, _ *Data, _ string) (int, error) {
-			if c.Response().Header.ContentLength() < 0 {
-				return appendInt(output, 0)
-			}
-			return appendInt(output, len(c.Response().Body()))
+			return appendInt(output, c.Response().Header.ContentLength())
 		},
 		TagRoute: func(output Buffer, c fiber.Ctx, _ *Data, _ string) (int, error) {
 			return output.WriteString(c.Route().Path)