Add logging functionality to middleware and test its execution

middleware.go

@@ -1,6 +1,7 @@
 package mux
 
 import (
+	"log"
 	"net/http"
 	"strings"
 )
@@ -10,6 +11,13 @@ import (
 // to it, and then calls the handler passed as parameter to the MiddlewareFunc.
 type MiddlewareFunc func(http.Handler) http.Handler
 
+// MiddlewareFuncWithLogging is a middleware function with optional logging.
+// It wraps a MiddlewareFunc and adds logging capabilities.
+type MiddlewareFuncWithLogging struct {
+	Handler MiddlewareFunc
+	Name    string
+}
+
 // middleware interface is anything which implements a MiddlewareFunc named Middleware.
 type middleware interface {
 	Middleware(handler http.Handler) http.Handler
@@ -20,13 +28,29 @@ func (mw MiddlewareFunc) Middleware(handler http.Handler) http.Handler {
 	return mw(handler)
 }
 
+// Middleware allows MiddlewareFuncWithLogging to implement the middleware interface.
+func (mw MiddlewareFuncWithLogging) Middleware(handler http.Handler) http.Handler {
+	return mw.Handler(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		log.Printf("Executing middleware: %s", mw.Name)
+		handler.ServeHTTP(w, r)
+	}))
+}
+
 // 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 {
 		r.middlewares = append(r.middlewares, fn)
 	}
 }
 
+// UseWithLogging appends a MiddlewareFuncWithLogging to the chain, allowing optional logging.
+func (r *Router) UseWithLogging(name string, mw MiddlewareFunc) {
+	r.useInterface(MiddlewareFuncWithLogging{
+		Handler: mw,
+		Name:    name,
+	})
+}
+
 // useInterface appends a middleware 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) useInterface(mw middleware) {
 	r.middlewares = append(r.middlewares, mw)
@@ -43,7 +67,17 @@ func (r *Route) Use(mwf ...MiddlewareFunc) *Route {
 	return r
 }
 
-// useInterface 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 Route. Route middleware are executed after the Router middleware but before the Route handler.
+// UseWithLogging appends a MiddlewareFuncWithLogging to the route's middleware chain.
+func (r *Route) UseWithLogging(name string, mw MiddlewareFunc) *Route {
+	r.useInterface(MiddlewareFuncWithLogging{
+		Handler: mw,
+		Name:    name,
+	})
+
+	return r
+}
+
+// useInterface appends a middleware 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 Route. Route middleware are executed after the Router middleware but before the Route handler.
 func (r *Route) useInterface(mw middleware) {
 	r.middlewares = append(r.middlewares, mw)
 }

middleware_test.go

@@ -3,7 +3,9 @@ package mux
 import (
 	"bytes"
 	"fmt"
+	"log"
 	"net/http"
+	"strings"
 	"testing"
 )
 
@@ -117,6 +119,40 @@ func TestMiddleware(t *testing.T) {
 	})
 }
 
+func TestMiddlewareExecutionWithLogging(t *testing.T) {
+	handlerStr := []byte("Logic\n")
+	logOutput := &bytes.Buffer{}
+	log.SetOutput(logOutput) // Redirect logs to the buffer for testing
+	defer log.SetOutput(nil) // Reset log output after the test
+
+	handlerFunc := func(w http.ResponseWriter, e *http.Request) {
+		_, err := w.Write(handlerStr)
+		if err != nil {
+			t.Fatalf("Failed writing HTTP response: %v", err)
+		}
+	}
+
+	router := NewRouter()
+	router.HandleFunc("/", handlerFunc)
+
+	router.UseWithLogging("TestMiddleware", func(h http.Handler) http.Handler {
+		return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+			h.ServeHTTP(w, r)
+		})
+	})
+
+	rw := NewRecorder()
+	req := newRequest("GET", "/")
+
+	router.ServeHTTP(rw, req)
+
+	expectedLog := "Executing middleware: TestMiddleware\n"
+	if !strings.Contains(logOutput.String(), expectedLog) {
+		t.Fatalf("Expected log output '%s', but got '%s'", expectedLog, logOutput.String())
+	}
+}
+
+
 func TestMiddlewareSubrouter(t *testing.T) {
 	router := NewRouter()
 	router.HandleFunc("/", dummyHandler).Methods("GET")