Added custom MethodNotAllowedHandler in Router

Author: maknahar

mux.go

@@ -43,6 +43,10 @@ func NewRouter() *Router {
 type Router struct {
 	// Configurable Handler to be used when no route matches.
 	NotFoundHandler http.Handler
+
+	// Configurable Handler to be used request has method mismatch with route
+	MethodNotAllowedHandler http.Handler
+
 	// Parent route, if this is a subrouter.
 	parent parentRoute
 	// Routes to be matched, in order.
@@ -69,6 +73,11 @@ func (r *Router) Match(req *http.Request, match *RouteMatch) bool {
 		}
 	}
 
+	if match.MatchErr == ErrMethodMismatch && r.MethodNotAllowedHandler != nil {
+		match.Handler = r.MethodNotAllowedHandler
+		return true
+	}
+
 	// Closest match for a router (includes sub-routers)
 	if r.NotFoundHandler != nil {
 		match.Handler = r.NotFoundHandler

mux_test.go

@@ -1876,8 +1876,7 @@ func TestNoMatchMethodErrorHandler(t *testing.T) {
 	func1 := func(w http.ResponseWriter, r *http.Request) {}
 
 	r := NewRouter()
-	s := r.Methods("GET", "POST").Subrouter()
-	s.HandleFunc("/", func1).Name("func1")
+	r.HandleFunc("/", func1).Methods("GET", "POST")
 
 	req, _ := http.NewRequest("PUT", "http://localhost/", nil)
 	match := new(RouteMatch)
@@ -1891,9 +1890,17 @@ func TestNoMatchMethodErrorHandler(t *testing.T) {
 		t.Error("Should get ErrMethodMismatch error")
 	}
 
-	resp := NewRecorder()
-	r.ServeHTTP(resp, req)
-	if resp.Code != 405 {
-		t.Errorf("Expecting code %v", 405)
+	//Add matching route now
+	r.HandleFunc("/", func1).Methods("PUT")
+
+	match = new(RouteMatch)
+	matched = r.Match(req, match)
+
+	if !matched {
+		t.Error("Should have matched route for methods")
+	}
+
+	if match.MatchErr != nil {
+		t.Error("Should not have any matching error. Found:", match.MatchErr)
 	}
 }

route.go

@@ -53,21 +53,26 @@ func (r *Route) Match(req *http.Request, match *RouteMatch) bool {
 		return false
 	}
 
+	var matchErr error
+
 	// Match everything.
 	for _, m := range r.matchers {
 		if matched := m.Match(req, match); !matched {
 			if _, ok := m.(methodMatcher); ok {
-				match.MatchErr = ErrMethodMismatch
+				matchErr = ErrMethodMismatch
 				continue
 			}
+			matchErr = nil
 			return false
 		}
 	}
 
-	if match.MatchErr != nil {
+	if matchErr != nil {
+		match.MatchErr = matchErr
 		return false
 	}
 
+	match.MatchErr = nil
 	// Yay, we have a match. Let's collect some info about it.
 	if match.Route == nil {
 		match.Route = r