New: context#NextOr && context#NextOrNotFound and some performance improvements on the awesome https://github.com/kataras/iris/pull/909 pushed a while ago

Former-commit-id: 35dd2ab80b69a5bea6f35f58e636bc11229d9921

README.md

@@ -195,7 +195,7 @@ First of all, the most correct way to begin with a web framework is to learn the
 
 Iris has a great collection of handlers[[1]](middleware/)[[2]](https://github.com/iris-contrib/middleware) that you can use side by side with your web apps. However you are not limited to them - you are free to use any third-party middleware that is compatible with the [net/http](https://golang.org/pkg/net/http/) package, [_examples/convert-handlers](_examples/convert-handlers) will show you the way.
 
-Iris, unlike others, is 100% compatible with the standards and that's why the majority of the big companies that adapt Go to their workflow, like a very famous US Television Network, trust Iris; it's always up-to-date and it will be aligned with the std `net/http` package which is modernized by the Go Author on each new release of the Go Programming Language forever.
+Iris, unlike others, is 100% compatible with the standards and that's why the majority of the big companies that adapt Go to their workflow, like a very famous US Television Network, trust Iris; it's up-to-date and it will be always aligned with the std `net/http` package which is modernized by the Go Authors on each new release of the Go Programming Language.
 
 ### Articles
 

_examples/routing/fallback-handlers/main.go

@@ -1,14 +1,12 @@
 package main
 
-import (
-	"github.com/kataras/iris"
-)
+import "github.com/kataras/iris"
 
 func main() {
 	app := iris.New()
 
 	// this works as expected now,
-	// will handle *all* expect DELETE requests, even if there is no routes
+	// will handle *all* expect DELETE requests, even if there is no routes.
 	app.Get("/action/{p}", h)
 
 	app.Run(iris.Addr(":8080"), iris.WithoutServerError(iris.ErrServerClosed))
@@ -20,8 +18,7 @@ func h(ctx iris.Context) {
 
 func fallbackHandler(ctx iris.Context) {
 	if ctx.Method() == "DELETE" {
-		ctx.Next()
-
+		ctx.NextOrNotFound()
 		return
 	}
 

context/context.go

@@ -309,7 +309,21 @@ type Context interface {
 	//
 	// Note: Custom context should override this method in order to be able to pass its own context.Context implementation.
 	Next()
-	// NextHandler returns(but it is NOT executes) the next handler from the handlers chain.
+	// NextOr checks if chain has a next handler, if so then it executes it
+	// otherwise it sets a new chain assigned to this Context based on the given handler(s)
+	// and executes its first handler.
+	//
+	// Returns true if next handler exists and executed, otherwise false.
+	//
+	// Note that if no next handler found and handlers are missing then
+	// it sends a Status Not Found (404) to the client and it stops the execution.
+	NextOr(handlers ...Handler) bool
+	// NextOrNotFound checks if chain has a next handler, if so then it executes it
+	// otherwise it sends a Status Not Found (404) to the client and stops the execution.
+	//
+	// Returns true if next handler exists and executed, otherwise false.
+	NextOrNotFound() bool
+	// NextHandler returns (it doesn't execute) the next handler from the handlers chain.
 	//
 	// Use .Skip() to skip this handler if needed to execute the next of this returning handler.
 	NextHandler() Handler
@@ -1262,7 +1276,39 @@ func (ctx *context) Next() { // or context.Next(ctx)
 	Next(ctx)
 }
 
-// NextHandler returns, but it doesn't executes, the next handler from the handlers chain.
+// NextOr checks if chain has a next handler, if so then it executes it
+// otherwise it sets a new chain assigned to this Context based on the given handler(s)
+// and executes its first handler.
+//
+// Returns true if next handler exists and executed, otherwise false.
+//
+// Note that if no next handler found and handlers are missing then
+// it sends a Status Not Found (404) to the client and it stops the execution.
+func (ctx *context) NextOr(handlers ...Handler) bool {
+	if next := ctx.NextHandler(); next != nil {
+		next(ctx)
+		ctx.Skip() // skip this handler from the chain.
+		return true
+	}
+
+	if len(handlers) == 0 {
+		ctx.NotFound()
+		ctx.StopExecution()
+		return false
+	}
+
+	ctx.Do(handlers)
+
+	return false
+}
+
+// NextOrNotFound checks if chain has a next handler, if so then it executes it
+// otherwise it sends a Status Not Found (404) to the client and stops the execution.
+//
+// Returns true if next handler exists and executed, otherwise false.
+func (ctx *context) NextOrNotFound() bool { return ctx.NextOr() }
+
+// NextHandler returns (it doesn't execute) the next handler from the handlers chain.
 //
 // Use .Skip() to skip this handler if needed to execute the next of this returning handler.
 func (ctx *context) NextHandler() Handler {

core/router/api_builder.go

@@ -90,7 +90,7 @@ type APIBuilder struct {
 	doneHandlers context.Handlers
 	// global done handlers, order doesn't matter
 	doneGlobalHandlers context.Handlers
-	// fallback stack, LIFO order
+	// fallback stack, LIFO order, initialized on first `Fallback`.
 	fallbackStack *FallbackStack
 	// the per-party
 	relativePath string
@@ -437,13 +437,13 @@ func (api *APIBuilder) DoneGlobal(handlers ...context.Handler) {
 // Fallback appends Handler(s) to the current fallback stack.
 // Handler(s) is(are) called from Fallback stack when no route found and before sending NotFound status.
 // Therefore Handler(s) in Fallback stack could send another thing than NotFound status,
-//   if `Context.Next()` method is not called.
+//   if `context.NextOrNotFound()` method is not called.
 // Done & DoneGlobal Handlers are not called.
 func (api *APIBuilder) Fallback(middleware ...context.Handler) {
 	api.fallbackStack.Add(middleware)
 }
 
-// FallBackStack returns Fallback stack, this is implementation of interface RoutesProvider
+// GetFallBackStack returns Fallback stack, this is implementation of interface RoutesProvider
 //   that is used in Router building by the RequestHandler.
 func (api *APIBuilder) GetFallBackStack() *FallbackStack {
 	return api.fallbackStack

core/router/fallback_stack.go

@@ -1,16 +1,12 @@
 package router
 
-import (
-	"net/http"
-
-	"github.com/kataras/iris/context"
-)
+import "github.com/kataras/iris/context"
 
 // FallbackStack is a stack (with LIFO calling order) for fallback handlers
 // A fallback handler(s) is(are) called from Fallback stack
 //   when no route found and before sending NotFound status.
 // Therefore Handler(s) in Fallback stack could send another thing than NotFound status,
-//   if `Context.Next()` method is not called.
+//   if `context#NextOrNotFound()` method is not called.
 // Done & DoneGlobal Handlers are not called.
 type FallbackStack struct {
 	parent   *FallbackStack
@@ -65,14 +61,5 @@ func (stk *FallbackStack) List() context.Handlers {
 	return res
 }
 
-// NewFallbackStack create a new Fallback stack with as first entry
-//   a handler which send NotFound status (the default)
-func NewFallbackStack() *FallbackStack {
-	return &FallbackStack{
-		handlers: context.Handlers{
-			func(ctx context.Context) {
-				ctx.StatusCode(http.StatusNotFound)
-			},
-		},
-	}
-}
+// NewFallbackStack create a new empty Fallback stack.
+func NewFallbackStack() *FallbackStack { return &FallbackStack{} }

core/router/fallback_stack_test.go

@@ -94,8 +94,7 @@ func TestFallbackStackCall(t *testing.T) {
 	// setup fallback handler
 	app.Fallback(func(ctx context.Context) {
 		if ctx.Method() != "GET" {
-			ctx.Next()
-
+			ctx.NextOrNotFound() //	it checks if we have next, otherwise fire 404 not found.
 			return
 		}
 

core/router/handler.go

@@ -38,6 +38,11 @@ type routerHandler struct {
 	trees         []*tree
 	hosts         bool // true if at least one route contains a Subdomain.
 	fallbackStack *FallbackStack
+	// on build: true if fallbackStack.Size() > 0,
+	// reduces the checks because fallbackStack is NEVER nil (api_builder.go always initializes it).
+	// If re-checked needed (serve-time fallback handler added)
+	// then a re-build/refresh of the application's router is necessary, as with every handler.
+	hasFallbackHandlers bool
 }
 
 var _ RequestHandler = &routerHandler{}
@@ -93,6 +98,7 @@ func (h *routerHandler) Build(provider RoutesProvider) error {
 	registeredRoutes := provider.GetRoutes()
 	h.trees = h.trees[0:0] // reset, inneed when rebuilding.
 	h.fallbackStack = provider.GetFallBackStack()
+	h.hasFallbackHandlers = h.fallbackStack.Size() > 0
 
 	// sort, subdomains goes first.
 	sort.Slice(registeredRoutes, func(i, j int) bool {
@@ -248,11 +254,12 @@ func (h *routerHandler) HandleRequest(ctx context.Context) {
 		}
 	}
 
-	if h.fallbackStack == nil {
-		ctx.StatusCode(http.StatusNotFound)
-	} else {
+	if h.hasFallbackHandlers {
 		ctx.Do(h.fallbackStack.List())
+		return
 	}
+
+	ctx.StatusCode(http.StatusNotFound)
 }
 
 // RouteExists checks if a route exists