✨ v3 (feature): new mounting system

app.go

@@ -618,33 +618,50 @@ func (app *App) GetRoutes(filterUseOption ...bool) []Route {
 
 // Use registers a middleware route that will match requests
 // with the provided prefix (which is optional and defaults to "/").
+// Also, you can pass another app instance as a sub-router along a routing path.
+// It's very useful to split up a large API as many independent routers and
+// compose them as a single service using Use. The fiber's error handler and
+// any of the fiber's sub apps are added to the application's error handlers
+// to be invoked on errors that happen within the prefix route.
 //
-//	app.Use(func(c fiber.Ctx) error {
-//	     return c.Next()
-//	})
-//	app.Use("/api", func(c fiber.Ctx) error {
-//	     return c.Next()
-//	})
-//	app.Use("/api", handler, func(c fiber.Ctx) error {
-//	     return c.Next()
-//	})
+//		app.Use(func(c fiber.Ctx) error {
+//		     return c.Next()
+//		})
+//		app.Use("/api", func(c fiber.Ctx) error {
+//		     return c.Next()
+//		})
+//		app.Use("/api", handler, func(c fiber.Ctx) error {
+//		     return c.Next()
+//		})
+//	 	subApp := fiber.New()
+//		app.Use("/mounted-path", subApp)
 //
 // This method will match all HTTP verbs: GET, POST, PUT, HEAD etc...
 func (app *App) Use(args ...any) Router {
 	var prefix string
+	var subApp *App
 	var handlers []Handler
 
 	for i := 0; i < len(args); i++ {
 		switch arg := args[i].(type) {
 		case string:
 			prefix = arg
+		case *App:
+			subApp = arg
 		case Handler:
 			handlers = append(handlers, arg)
 		default:
 			panic(fmt.Sprintf("use: invalid handler %v\n", reflect.TypeOf(arg)))
 		}
 	}
+
+	if subApp != nil {
+		app.mount(prefix, subApp)
+		return app
+	}
+
 	app.register([]string{methodUse}, prefix, nil, handlers...)
+
 	return app
 }
 

group.go

@@ -39,32 +39,50 @@ func (grp *Group) Name(name string) Router {
 
 // Use registers a middleware route that will match requests
 // with the provided prefix (which is optional and defaults to "/").
+// Also, you can pass another app instance as a sub-router along a routing path.
+// It's very useful to split up a large API as many independent routers and
+// compose them as a single service using Use. The fiber's error handler and
+// any of the fiber's sub apps are added to the application's error handlers
+// to be invoked on errors that happen within the prefix route.
 //
-//	app.Use(func(c fiber.Ctx) error {
-//	     return c.Next()
-//	})
-//	app.Use("/api", func(c fiber.Ctx) error {
-//	     return c.Next()
-//	})
-//	app.Use("/api", handler, func(c fiber.Ctx) error {
-//	     return c.Next()
-//	})
+//		app.Use(func(c fiber.Ctx) error {
+//		     return c.Next()
+//		})
+//		app.Use("/api", func(c fiber.Ctx) error {
+//		     return c.Next()
+//		})
+//		app.Use("/api", handler, func(c fiber.Ctx) error {
+//		     return c.Next()
+//		})
+//	 	subApp := fiber.New()
+//		app.Use("/mounted-path", subApp)
 //
 // This method will match all HTTP verbs: GET, POST, PUT, HEAD etc...
 func (grp *Group) Use(args ...any) Router {
 	prefix := ""
+	var subApp *App
 	var handlers []Handler
+
 	for i := 0; i < len(args); i++ {
 		switch arg := args[i].(type) {
 		case string:
 			prefix = arg
+		case *App:
+			subApp = arg
 		case Handler:
 			handlers = append(handlers, arg)
 		default:
 			panic(fmt.Sprintf("use: invalid handler %v\n", reflect.TypeOf(arg)))
 		}
 	}
+
+	if subApp != nil {
+		grp.mount(prefix, subApp)
+		return grp
+	}
+
 	grp.app.register([]string{methodUse}, getGroupPath(grp.Prefix, prefix), nil, handlers...)
+
 	return grp
 }
 

hooks_test.go

@@ -30,15 +30,15 @@ func Test_Hook_OnRoute(t *testing.T) {
 	subApp := New()
 	subApp.Get("/test", testSimpleHandler)
 
-	app.Mount("/sub", subApp)
+	app.Use("/sub", subApp)
 }
 
 func Test_Hook_OnRoute_Mount(t *testing.T) {
 	t.Parallel()
 
 	app := New()
 	subApp := New()
-	app.Mount("/sub", subApp)
+	app.Use("/sub", subApp)
 
 	subApp.Hooks().OnRoute(func(r Route) error {
 		require.Equal(t, "/sub/test", r.Path)
@@ -77,7 +77,7 @@ func Test_Hook_OnName(t *testing.T) {
 	subApp.Get("/test", testSimpleHandler)
 	subApp.Get("/test2", testSimpleHandler)
 
-	app.Mount("/sub", subApp)
+	app.Use("/sub", subApp)
 
 	require.Equal(t, "index", buf.String())
 }
@@ -124,7 +124,7 @@ func Test_Hook_OnGroup_Mount(t *testing.T) {
 
 	app := New()
 	micro := New()
-	micro.Mount("/john", app)
+	micro.Use("/john", app)
 
 	app.Hooks().OnGroup(func(g Group) error {
 		require.Equal(t, "/john/v1", g.Prefix)
@@ -255,5 +255,5 @@ func Test_Hook_OnMount(t *testing.T) {
 		return nil
 	})
 
-	app.Mount("/sub", subApp)
+	app.Use("/sub", subApp)
 }

mount.go

@@ -36,7 +36,7 @@ func newMountFields(app *App) *mountFields {
 // compose them as a single service using Mount. The fiber's error handler and
 // any of the fiber's sub apps are added to the application's error handlers
 // to be invoked on errors that happen within the prefix route.
-func (app *App) Mount(prefix string, fiber *App) Router {
+func (app *App) mount(prefix string, fiber *App) Router {
 	prefix = strings.TrimRight(prefix, "/")
 	if prefix == "" {
 		prefix = "/"
@@ -58,8 +58,10 @@ func (app *App) Mount(prefix string, fiber *App) Router {
 
 // Mount attaches another app instance as a sub-router along a routing path.
 // It's very useful to split up a large API as many independent routers and
-// compose them as a single service using Mount.
-func (grp *Group) Mount(prefix string, fiber *App) Router {
+// compose them as a single service using Mount. The fiber's error handler and
+// any of the fiber's sub apps are added to the application's error handlers
+// to be invoked on errors that happen within the prefix route.
+func (grp *Group) mount(prefix string, fiber *App) Router {
 	groupPath := getGroupPath(grp.Prefix, prefix)
 	groupPath = strings.TrimRight(groupPath, "/")
 	if groupPath == "" {

mount_test.go

@@ -21,7 +21,7 @@ func Test_App_Mount(t *testing.T) {
 	})
 
 	app := New()
-	app.Mount("/john", micro)
+	app.Use("/john", micro)
 	resp, err := app.Test(httptest.NewRequest(MethodGet, "/john/doe", nil))
 	require.Equal(t, nil, err, "app.Test(req)")
 	require.Equal(t, 200, resp.StatusCode, "Status code")
@@ -35,9 +35,9 @@ func Test_App_Mount_Nested(t *testing.T) {
 	two := New()
 	three := New()
 
-	two.Mount("/three", three)
-	app.Mount("/one", one)
-	one.Mount("/two", two)
+	two.Use("/three", three)
+	app.Use("/one", one)
+	one.Use("/two", two)
 
 	one.Get("/doe", func(c Ctx) error {
 		return c.SendStatus(StatusOK)
@@ -73,9 +73,9 @@ func Test_App_MountPath(t *testing.T) {
 	two := New()
 	three := New()
 
-	two.Mount("/three", three)
-	one.Mount("/two", two)
-	app.Mount("/one", one)
+	two.Use("/three", three)
+	one.Use("/two", two)
+	app.Use("/one", one)
 
 	require.Equal(t, "/one", one.MountPath())
 	require.Equal(t, "/one/two", two.MountPath())
@@ -96,7 +96,7 @@ func Test_App_ErrorHandler_GroupMount(t *testing.T) {
 
 	app := New()
 	v1 := app.Group("/v1")
-	v1.Mount("/john", micro)
+	v1.Use("/john", micro)
 
 	resp, err := app.Test(httptest.NewRequest(MethodGet, "/v1/john/doe", nil))
 	testErrorResponse(t, err, resp, "1: custom error")
@@ -115,7 +115,7 @@ func Test_App_ErrorHandler_GroupMountRootLevel(t *testing.T) {
 
 	app := New()
 	v1 := app.Group("/v1")
-	v1.Mount("/", micro)
+	v1.Use("/", micro)
 
 	resp, err := app.Test(httptest.NewRequest(MethodGet, "/v1/john/doe", nil))
 	testErrorResponse(t, err, resp, "1: custom error")
@@ -130,7 +130,7 @@ func Test_App_Group_Mount(t *testing.T) {
 
 	app := New()
 	v1 := app.Group("/v1")
-	v1.Mount("/john", micro)
+	v1.Use("/john", micro)
 
 	resp, err := app.Test(httptest.NewRequest(MethodGet, "/v1/john/doe", nil))
 	require.Equal(t, nil, err, "app.Test(req)")
@@ -150,7 +150,7 @@ func Test_App_UseMountedErrorHandler(t *testing.T) {
 		return errors.New("something happened")
 	})
 
-	app.Mount("/api", fiber)
+	app.Use("/api", fiber)
 
 	resp, err := app.Test(httptest.NewRequest(MethodGet, "/api", nil))
 	testErrorResponse(t, err, resp, "hi, i'm a custom error")
@@ -168,7 +168,7 @@ func Test_App_UseMountedErrorHandlerRootLevel(t *testing.T) {
 		return errors.New("something happened")
 	})
 
-	app.Mount("/", fiber)
+	app.Use("/", fiber)
 
 	resp, err := app.Test(httptest.NewRequest(MethodGet, "/api", nil))
 	testErrorResponse(t, err, resp, "hi, i'm a custom error")
@@ -196,7 +196,7 @@ func Test_App_UseMountedErrorHandlerForBestPrefixMatch(t *testing.T) {
 	subfiber.Get("/", func(c Ctx) error {
 		return errors.New("something happened")
 	})
-	subfiber.Mount("/third", tripleSubFiber)
+	subfiber.Use("/third", tripleSubFiber)
 
 	f := func(c Ctx, err error) error {
 		return c.Status(200).SendString("hi, i'm a custom error")
@@ -207,9 +207,9 @@ func Test_App_UseMountedErrorHandlerForBestPrefixMatch(t *testing.T) {
 	fiber.Get("/", func(c Ctx) error {
 		return errors.New("something happened")
 	})
-	fiber.Mount("/sub", subfiber)
+	fiber.Use("/sub", subfiber)
 
-	app.Mount("/api", fiber)
+	app.Use("/api", fiber)
 
 	resp, err := app.Test(httptest.NewRequest(MethodGet, "/api/sub", nil))
 	require.Equal(t, nil, err, "/api/sub req")
@@ -246,7 +246,7 @@ func Test_Ctx_Render_Mount(t *testing.T) {
 	})
 
 	app := New()
-	app.Mount("/hello", sub)
+	app.Use("/hello", sub)
 
 	resp, err := app.Test(httptest.NewRequest(MethodGet, "/hello/a", nil))
 	require.Equal(t, StatusOK, resp.StatusCode, "Status code")
@@ -301,8 +301,8 @@ func Test_Ctx_Render_Mount_ParentOrSubHasViews(t *testing.T) {
 		return c.Render("bruh.tmpl", Map{})
 	})
 
-	sub.Mount("/bruh", sub2)
-	app.Mount("/hello", sub)
+	sub.Use("/bruh", sub2)
+	app.Use("/hello", sub)
 
 	resp, err := app.Test(httptest.NewRequest(MethodGet, "/hello/world/a", nil))
 	require.Equal(t, StatusOK, resp.StatusCode, "Status code")
@@ -348,7 +348,7 @@ func Test_Ctx_Render_MountGroup(t *testing.T) {
 
 	app := New()
 	v1 := app.Group("/v1")
-	v1.Mount("/john", micro)
+	v1.Use("/john", micro)
 
 	resp, err := app.Test(httptest.NewRequest(MethodGet, "/v1/john/doe", nil))
 	require.Equal(t, nil, err, "app.Test(req)")

router.go

@@ -38,8 +38,6 @@ type Router interface {
 
 	Route(path string) Register
 
-	Mount(prefix string, fiber *App) Router
-
 	Name(name string) Router
 }