fixes #3038 "v3 Flash Message with redirect is not working" (#3046)

* fixes #3038
🐞 [Bug]: v3 Flash Message with redirect is not working #3038

* fixes #3038
🐞 [Bug]: v3 Flash Message with redirect is not working #3038

redirect.go

@@ -182,6 +182,8 @@ func (r *Redirect) To(location string) error {
 	r.c.setCanonical(HeaderLocation, location)
 	r.c.Status(r.status)
 
+	r.processFlashMessages()
+
 	return nil
 }
 
@@ -200,38 +202,6 @@ func (r *Redirect) Route(name string, config ...RedirectConfig) error {
 		return err
 	}
 
-	// Flash messages
-	if len(r.messages) > 0 || len(r.oldInput) > 0 {
-		messageText := bytebufferpool.Get()
-		defer bytebufferpool.Put(messageText)
-
-		// flash messages
-		for i, message := range r.messages {
-			messageText.WriteString(message)
-			// when there are more messages or oldInput -> add a comma
-			if len(r.messages)-1 != i || (len(r.messages)-1 == i && len(r.oldInput) > 0) {
-				messageText.WriteString(CookieDataSeparator)
-			}
-		}
-		r.messages = r.messages[:0]
-
-		// old input data
-		i := 1
-		for k, v := range r.oldInput {
-			messageText.WriteString(OldInputDataPrefix + k + CookieDataAssigner + v)
-			if len(r.oldInput) != i {
-				messageText.WriteString(CookieDataSeparator)
-			}
-			i++
-		}
-
-		r.c.Cookie(&Cookie{
-			Name:        FlashCookieName,
-			Value:       r.c.app.getString(messageText.Bytes()),
-			SessionOnly: true,
-		})
-	}
-
 	// Check queries
 	if len(cfg.Queries) > 0 {
 		queryText := bytebufferpool.Get()
@@ -270,8 +240,8 @@ func (r *Redirect) Back(fallback ...string) error {
 	return r.To(location)
 }
 
-// setFlash is a method to get flash messages before removing them
+// parseAndClearFlashMessages is a method to get flash messages before removing them
-func (r *Redirect) setFlash() {
+func (r *Redirect) parseAndClearFlashMessages() {
 	// parse flash messages
 	cookieValue := r.c.Cookies(FlashCookieName)
 
@@ -289,6 +259,42 @@ func (r *Redirect) setFlash() {
 	r.c.ClearCookie(FlashCookieName)
 }
 
+// processFlashMessages is a helper function to process flash messages and old input data
+// and set them as cookies
+func (r *Redirect) processFlashMessages() {
+	// Flash messages
+	if len(r.messages) > 0 || len(r.oldInput) > 0 {
+		messageText := bytebufferpool.Get()
+		defer bytebufferpool.Put(messageText)
+
+		// flash messages
+		for i, message := range r.messages {
+			messageText.WriteString(message)
+			// when there are more messages or oldInput -> add a comma
+			if len(r.messages)-1 != i || (len(r.messages)-1 == i && len(r.oldInput) > 0) {
+				messageText.WriteString(CookieDataSeparator)
+			}
+		}
+		r.messages = r.messages[:0]
+
+		// old input data
+		i := 1
+		for k, v := range r.oldInput {
+			messageText.WriteString(OldInputDataPrefix + k + CookieDataAssigner + v)
+			if len(r.oldInput) != i {
+				messageText.WriteString(CookieDataSeparator)
+			}
+			i++
+		}
+
+		r.c.Cookie(&Cookie{
+			Name:        FlashCookieName,
+			Value:       r.c.app.getString(messageText.Bytes()),
+			SessionOnly: true,
+		})
+	}
+}
+
 // parseMessage is a helper function to parse flash messages and old input data
 func parseMessage(raw string) (string, string) { //nolint: revive // not necessary
 	if i := findNextNonEscapedCharsetPosition(raw, []byte(CookieDataAssigner)); i != -1 {

redirect_test.go

@@ -34,6 +34,24 @@ func Test_Redirect_To(t *testing.T) {
 	require.Equal(t, "http://example.com", string(c.Response().Header.Peek(HeaderLocation)))
 }
 
+// go test -run Test_Redirect_To_WithFlashMessages
+func Test_Redirect_To_WithFlashMessages(t *testing.T) {
+	t.Parallel()
+	app := New()
+	c := app.AcquireCtx(&fasthttp.RequestCtx{})
+
+	err := c.Redirect().With("success", "1").With("message", "test").To("http://example.com")
+	require.NoError(t, err)
+	require.Equal(t, 302, c.Response().StatusCode())
+	require.Equal(t, "http://example.com", string(c.Response().Header.Peek(HeaderLocation)))
+
+	equal := c.GetRespHeader(HeaderSetCookie) == "fiber_flash=success:1,message:test; path=/; SameSite=Lax" || c.GetRespHeader(HeaderSetCookie) == "fiber_flash=message:test,success:1; path=/; SameSite=Lax"
+	require.True(t, equal)
+
+	c.Redirect().parseAndClearFlashMessages()
+	require.Equal(t, "fiber_flash=; expires=Tue, 10 Nov 2009 23:00:00 GMT", c.GetRespHeader(HeaderSetCookie))
+}
+
 // go test -run Test_Redirect_Route_WithParams
 func Test_Redirect_Route_WithParams(t *testing.T) {
 	t.Parallel()
@@ -149,6 +167,29 @@ func Test_Redirect_Back(t *testing.T) {
 	require.ErrorAs(t, err, &ErrRedirectBackNoFallback)
 }
 
+// go test -run Test_Redirect_Back_WithFlashMessages
+func Test_Redirect_Back_WithFlashMessages(t *testing.T) {
+	t.Parallel()
+
+	app := New()
+	app.Get("/user", func(c Ctx) error {
+		return c.SendString("user")
+	}).Name("user")
+
+	c := app.AcquireCtx(&fasthttp.RequestCtx{}).(*DefaultCtx) //nolint:errcheck, forcetypeassert // not needed
+
+	err := c.Redirect().With("success", "1").With("message", "test").Back("/")
+	require.NoError(t, err)
+	require.Equal(t, 302, c.Response().StatusCode())
+	require.Equal(t, "/", string(c.Response().Header.Peek(HeaderLocation)))
+
+	equal := c.GetRespHeader(HeaderSetCookie) == "fiber_flash=success:1,message:test; path=/; SameSite=Lax" || c.GetRespHeader(HeaderSetCookie) == "fiber_flash=message:test,success:1; path=/; SameSite=Lax"
+	require.True(t, equal)
+
+	c.Redirect().parseAndClearFlashMessages()
+	require.Equal(t, "fiber_flash=; expires=Tue, 10 Nov 2009 23:00:00 GMT", c.GetRespHeader(HeaderSetCookie))
+}
+
 // go test -run Test_Redirect_Back_WithReferer
 func Test_Redirect_Back_WithReferer(t *testing.T) {
 	t.Parallel()
@@ -188,7 +229,7 @@ func Test_Redirect_Route_WithFlashMessages(t *testing.T) {
 	equal := c.GetRespHeader(HeaderSetCookie) == "fiber_flash=success:1,message:test; path=/; SameSite=Lax" || c.GetRespHeader(HeaderSetCookie) == "fiber_flash=message:test,success:1; path=/; SameSite=Lax"
 	require.True(t, equal)
 
-	c.Redirect().setFlash()
+	c.Redirect().parseAndClearFlashMessages()
 	require.Equal(t, "fiber_flash=; expires=Tue, 10 Nov 2009 23:00:00 GMT", c.GetRespHeader(HeaderSetCookie))
 }
 
@@ -216,12 +257,12 @@ func Test_Redirect_Route_WithOldInput(t *testing.T) {
 	require.Contains(t, c.GetRespHeader(HeaderSetCookie), ",old_input_data_id:1")
 	require.Contains(t, c.GetRespHeader(HeaderSetCookie), ",old_input_data_name:tom")
 
-	c.Redirect().setFlash()
+	c.Redirect().parseAndClearFlashMessages()
 	require.Equal(t, "fiber_flash=; expires=Tue, 10 Nov 2009 23:00:00 GMT", c.GetRespHeader(HeaderSetCookie))
 }
 
-// go test -run Test_Redirect_setFlash
+// go test -run Test_Redirect_parseAndClearFlashMessages
-func Test_Redirect_setFlash(t *testing.T) {
+func Test_Redirect_parseAndClearFlashMessages(t *testing.T) {
 	t.Parallel()
 
 	app := New()
@@ -233,7 +274,7 @@ func Test_Redirect_setFlash(t *testing.T) {
 
 	c.Request().Header.Set(HeaderCookie, "fiber_flash=success:1,message:test,old_input_data_name:tom,old_input_data_id:1")
 
-	c.Redirect().setFlash()
+	c.Redirect().parseAndClearFlashMessages()
 
 	require.Equal(t, "fiber_flash=; expires=Tue, 10 Nov 2009 23:00:00 GMT", c.GetRespHeader(HeaderSetCookie))
 
@@ -416,12 +457,12 @@ func Benchmark_Redirect_Route_WithFlashMessages(b *testing.B) {
 	equal := c.GetRespHeader(HeaderSetCookie) == "fiber_flash=success:1,message:test; path=/; SameSite=Lax" || c.GetRespHeader(HeaderSetCookie) == "fiber_flash=message:test,success:1; path=/; SameSite=Lax"
 	require.True(b, equal)
 
-	c.Redirect().setFlash()
+	c.Redirect().parseAndClearFlashMessages()
 	require.Equal(b, "fiber_flash=; expires=Tue, 10 Nov 2009 23:00:00 GMT", c.GetRespHeader(HeaderSetCookie))
 }
 
-// go test -v -run=^$ -bench=Benchmark_Redirect_setFlash -benchmem -count=4
+// go test -v -run=^$ -bench=Benchmark_Redirect_parseAndClearFlashMessages -benchmem -count=4
-func Benchmark_Redirect_setFlash(b *testing.B) {
+func Benchmark_Redirect_parseAndClearFlashMessages(b *testing.B) {
 	app := New()
 	app.Get("/user", func(c Ctx) error {
 		return c.SendString("user")
@@ -435,7 +476,7 @@ func Benchmark_Redirect_setFlash(b *testing.B) {
 	b.ResetTimer()
 
 	for n := 0; n < b.N; n++ {
-		c.Redirect().setFlash()
+		c.Redirect().parseAndClearFlashMessages()
 	}
 
 	require.Equal(b, "fiber_flash=; expires=Tue, 10 Nov 2009 23:00:00 GMT", c.GetRespHeader(HeaderSetCookie))
@@ -449,6 +490,27 @@ func Benchmark_Redirect_setFlash(b *testing.B) {
 	require.Equal(b, map[string]string{"id": "1", "name": "tom"}, c.Redirect().OldInputs())
 }
 
+// go test -v -run=^$ -bench=Benchmark_Redirect_processFlashMessages -benchmem -count=4
+func Benchmark_Redirect_processFlashMessages(b *testing.B) {
+	app := New()
+	app.Get("/user", func(c Ctx) error {
+		return c.SendString("user")
+	}).Name("user")
+
+	c := app.AcquireCtx(&fasthttp.RequestCtx{}).(*DefaultCtx) //nolint:errcheck, forcetypeassert // not needed
+
+	c.Redirect().With("success", "1").With("message", "test")
+
+	b.ReportAllocs()
+	b.ResetTimer()
+
+	for n := 0; n < b.N; n++ {
+		c.Redirect().processFlashMessages()
+	}
+
+	require.Equal(b, "fiber_flash=success:1,message:test; path=/; SameSite=Lax", c.GetRespHeader(HeaderSetCookie))
+}
+
 // go test -v -run=^$ -bench=Benchmark_Redirect_Messages -benchmem -count=4
 func Benchmark_Redirect_Messages(b *testing.B) {
 	app := New()
@@ -459,7 +521,7 @@ func Benchmark_Redirect_Messages(b *testing.B) {
 	c := app.AcquireCtx(&fasthttp.RequestCtx{}).(*DefaultCtx) //nolint:errcheck, forcetypeassert // not needed
 
 	c.Request().Header.Set(HeaderCookie, "fiber_flash=success:1,message:test,old_input_data_name:tom,old_input_data_id:1")
-	c.Redirect().setFlash()
+	c.Redirect().parseAndClearFlashMessages()
 
 	var msgs map[string]string
 
@@ -484,7 +546,7 @@ func Benchmark_Redirect_OldInputs(b *testing.B) {
 	c := app.AcquireCtx(&fasthttp.RequestCtx{}).(*DefaultCtx) //nolint:errcheck, forcetypeassert // not needed
 
 	c.Request().Header.Set(HeaderCookie, "fiber_flash=success:1,message:test,old_input_data_name:tom,old_input_data_id:1")
-	c.Redirect().setFlash()
+	c.Redirect().parseAndClearFlashMessages()
 
 	var oldInputs map[string]string
 
@@ -509,7 +571,7 @@ func Benchmark_Redirect_Message(b *testing.B) {
 	c := app.AcquireCtx(&fasthttp.RequestCtx{}).(*DefaultCtx) //nolint:errcheck, forcetypeassert // not needed
 
 	c.Request().Header.Set(HeaderCookie, "fiber_flash=success:1,message:test,old_input_data_name:tom,old_input_data_id:1")
-	c.Redirect().setFlash()
+	c.Redirect().parseAndClearFlashMessages()
 
 	var msg string
 
@@ -534,7 +596,7 @@ func Benchmark_Redirect_OldInput(b *testing.B) {
 	c := app.AcquireCtx(&fasthttp.RequestCtx{}).(*DefaultCtx) //nolint:errcheck, forcetypeassert // not needed
 
 	c.Request().Header.Set(HeaderCookie, "fiber_flash=success:1,message:test,old_input_data_name:tom,old_input_data_id:1")
-	c.Redirect().setFlash()
+	c.Redirect().parseAndClearFlashMessages()
 
 	var input string
 

router.go

@@ -225,7 +225,7 @@ func (app *App) requestHandler(rctx *fasthttp.RequestCtx) {
 
 	// check flash messages
 	if strings.Contains(utils.UnsafeString(c.Request().Header.RawHeaders()), FlashCookieName) {
-		c.Redirect().setFlash()
+		c.Redirect().parseAndClearFlashMessages()
 	}
 
 	// Find match in stack