Add fallback handlers

Former-commit-id: f7e9bd17076a10e1ed1702780d7ce9e89f00b592

core/router/handler.go

@@ -22,6 +22,8 @@ type RequestHandler interface {
 	HandleRequest(context.Context)
 	// Build  should builds the handler, it's being called on router's BuildRouter.
 	Build(provider RoutesProvider) error
+	// RouteExists checks if a route exists
+	RouteExists(method, path string, ctx context.Context) bool
 }
 
 type tree struct {
@@ -84,12 +86,13 @@ type RoutesProvider interface { // api builder
 	GetRoutes() []*Route
 	GetRoute(routeName string) *Route
 
-	FallBackStack() *FallbackStack
+	GetFallBackStack() *FallbackStack
 }
 
 func (h *routerHandler) Build(provider RoutesProvider) error {
 	registeredRoutes := provider.GetRoutes()
 	h.trees = h.trees[0:0] // reset, inneed when rebuilding.
+	h.fallbackStack = provider.GetFallBackStack()
 
 	// sort, subdomains goes first.
 	sort.Slice(registeredRoutes, func(i, j int) bool {
@@ -245,5 +248,62 @@ func (h *routerHandler) HandleRequest(ctx context.Context) {
 		}
 	}
 
-	ctx.Do(h.fallbackStack.list())
+	if h.fallbackStack == nil {
+		ctx.StatusCode(http.StatusNotFound)
+	} else {
+		ctx.Do(h.fallbackStack.List())
+	}
+}
+
+// RouteExists checks if a route exists
+func (h *routerHandler) RouteExists(method, path string, ctx context.Context) bool {
+	for i := range h.trees {
+		t := h.trees[i]
+		if method != t.Method {
+			continue
+		}
+
+		if h.hosts && t.Subdomain != "" {
+			requestHost := ctx.Host()
+			if netutil.IsLoopbackSubdomain(requestHost) {
+				// this fixes a bug when listening on
+				// 127.0.0.1:8080 for example
+				// and have a wildcard subdomain and a route registered to root domain.
+				continue // it's not a subdomain, it's something like 127.0.0.1 probably
+			}
+			// it's a dynamic wildcard subdomain, we have just to check if ctx.subdomain is not empty
+			if t.Subdomain == SubdomainWildcardIndicator {
+				// mydomain.com -> invalid
+				// localhost -> invalid
+				// sub.mydomain.com -> valid
+				// sub.localhost -> valid
+				serverHost := ctx.Application().ConfigurationReadOnly().GetVHost()
+				if serverHost == requestHost {
+					continue // it's not a subdomain, it's a full domain (with .com...)
+				}
+
+				dotIdx := strings.IndexByte(requestHost, '.')
+				slashIdx := strings.IndexByte(requestHost, '/')
+				if dotIdx > 0 && (slashIdx == -1 || slashIdx > dotIdx) {
+					// if "." was found anywhere but not at the first path segment (host).
+				} else {
+					continue
+				}
+				// continue to that, any subdomain is valid.
+			} else if !strings.HasPrefix(requestHost, t.Subdomain) { // t.Subdomain contains the dot.
+				continue
+			}
+		}
+
+		_, handlers := t.Nodes.Find(path, ctx.Params())
+		if len(handlers) > 0 {
+			// found
+			return true
+		}
+
+		// not found or method not allowed.
+		break
+	}
+
+	return false
 }