Create new helper method for creating middlewares from a closure/anonymous function

middleware.go

@@ -20,6 +20,27 @@ func (mw MiddlewareFunc) Middleware(handler http.Handler) http.Handler {
 	return mw(handler)
 }
 
+// NewMiddleware helper method which allows creating a middleware from a function which receives the response and request.
+// The typical case would be passing a closure
+func NewMiddleware(mw func(http.ResponseWriter, *http.Request)) MiddlewareFunc {
+	return func(handler http.Handler) http.Handler {
+		return &genericMW{
+			process: func(w http.ResponseWriter, r *http.Request) {
+				mw(w, r)
+				handler.ServeHTTP(w, r)
+			},
+		}
+	}
+}
+
+// genericMW is for creating a middleware from a closure, it's used in the public method NewMiddleware
+type genericMW struct {
+	process func(http.ResponseWriter, *http.Request)
+}
+func (instance *genericMW) ServeHTTP(w http.ResponseWriter, req *http.Request) {
+	instance.process(w, req)
+}
+
 // Use appends a MiddlewareFunc to the chain. Middleware can be used to intercept or otherwise modify requests and/or responses, and are executed in the order that they are applied to the Router.
 func (r *Router) Use(mwf ...MiddlewareFunc) {
 	for _, fn := range mwf {

middleware_test.go

@@ -3,6 +3,7 @@ package mux
 import (
 	"bytes"
 	"net/http"
+	"net/http/httptest"
 	"testing"
 )
 
@@ -563,3 +564,36 @@ func TestMiddlewareOnMultiSubrouter(t *testing.T) {
 		}
 	})
 }
+
+func TestNewMiddleware(t *testing.T) {
+
+	mwFuncCalls := 0
+
+	handler := &mockHandler{
+		serverHttp: func(w http.ResponseWriter, r *http.Request) {
+			if mwFuncCalls != 1 {
+				t.Fatalf("Expected Handler to be called after mw run. However, the middleware run {%d} times before the handler.", mwFuncCalls)
+			}
+			mwFuncCalls++
+		},
+	}
+
+	newHandler := NewMiddleware(func(http.ResponseWriter, *http.Request) {
+		mwFuncCalls++
+	}).Middleware(handler)
+
+	newHandler.ServeHTTP(&httptest.ResponseRecorder{}, &http.Request{})
+
+	if mwFuncCalls != 2 {
+		t.Fatalf("Expected mwFuncCalls to be 2, but got {%d}", mwFuncCalls)
+	}
+
+}
+
+type mockHandler struct {
+	serverHttp func(writer http.ResponseWriter, request *http.Request)
+}
+
+func (d *mockHandler) ServeHTTP(writer http.ResponseWriter, request *http.Request) {
+	d.serverHttp(writer, request)
+}