middleware stacking bug fix

mux.go

@@ -4,6 +4,7 @@ import (
 	"fmt"
 	"io"
 	"net/http"
+	"slices"
 	"strings"
 	"sync/atomic"
 )
@@ -35,37 +36,38 @@ func (m *Mux) Use(h ...func(http.Handler) http.Handler) {
 	if m == nil {
 		panic("mux: func Use was called on nil")
 	}
+
 	m.middlewares = append(m.middlewares, h...)
 }
 
 // GET method route
-func (m *Mux) GET(pattern string, h http.HandlerFunc) {
+func (m *Mux) GET(pattern string, h http.HandlerFunc, mw ...func(http.Handler) http.Handler) {
-	m.handle(http.MethodGet, pattern, h)
+	m.handle(http.MethodGet, pattern, h, mw...)
 }
 
 // HEAD method route
-func (m *Mux) HEAD(pattern string, h http.HandlerFunc) {
+func (m *Mux) HEAD(pattern string, h http.HandlerFunc, mw ...func(http.Handler) http.Handler) {
-	m.handle(http.MethodHead, pattern, h)
+	m.handle(http.MethodHead, pattern, h, mw...)
 }
 
 // POST method route
-func (m *Mux) POST(pattern string, h http.HandlerFunc) {
+func (m *Mux) POST(pattern string, h http.HandlerFunc, mw ...func(http.Handler) http.Handler) {
-	m.handle(http.MethodPost, pattern, h)
+	m.handle(http.MethodPost, pattern, h, mw...)
 }
 
 // PUT method route
-func (m *Mux) PUT(pattern string, h http.HandlerFunc) {
+func (m *Mux) PUT(pattern string, h http.HandlerFunc, mw ...func(http.Handler) http.Handler) {
-	m.handle(http.MethodPut, pattern, h)
+	m.handle(http.MethodPut, pattern, h, mw...)
 }
 
 // PATCH method route
-func (m *Mux) PATCH(pattern string, h http.HandlerFunc) {
+func (m *Mux) PATCH(pattern string, h http.HandlerFunc, mw ...func(http.Handler) http.Handler) {
-	m.handle(http.MethodPatch, pattern, h)
+	m.handle(http.MethodPatch, pattern, h, mw...)
 }
 
 // DELETE method route
-func (m *Mux) DELETE(pattern string, h http.HandlerFunc) {
+func (m *Mux) DELETE(pattern string, h http.HandlerFunc, mw ...func(http.Handler) http.Handler) {
-	m.handle(http.MethodDelete, pattern, h)
+	m.handle(http.MethodDelete, pattern, h, mw...)
 }
 
 // CONNECT method route
@@ -86,7 +88,7 @@ func (m *Mux) TRACE(pattern string, h http.HandlerFunc) {
 // handle registers the handler for the given pattern.
 // If the given pattern conflicts, with one that is already registered, HandleFunc
 // panics.
-func (m *Mux) handle(method, pattern string, h http.HandlerFunc) {
+func (m *Mux) handle(method, pattern string, h http.HandlerFunc, mw ...func(http.Handler) http.Handler) {
 	if m == nil {
 		panic("mux: func Handle() was called on nil")
 	}
@@ -100,19 +102,20 @@ func (m *Mux) handle(method, pattern string, h http.HandlerFunc) {
 	}
 
 	path := fmt.Sprintf("%s %s", method, pattern)
-	m.mux.Handle(path, stack(m.middlewares, h))
+	if len(mw) > 0 {
+		m.mux.Handle(path, stack(h, copyMW(m.middlewares, mw)))
+	} else {
+		m.mux.Handle(path, stack(h, m.middlewares))
+	}
+
 	m.routes.Add(path)
 }
 
 // With adds inline middlewares for an endpoint handler.
-func (m *Mux) With(middleware ...func(http.Handler) http.Handler) *Mux {
+func (m *Mux) With(mw ...func(http.Handler) http.Handler) *Mux {
-	mws := make([]func(http.Handler) http.Handler, len(m.middlewares))
-	copy(mws, m.middlewares)
-	mws = append(mws, middleware...)
-
 	im := &Mux{
 		mux:         m.mux,
-		middlewares: mws,
+		middlewares: copyMW(m.middlewares, mw),
 		routes:      m.routes,
 	}
 
@@ -152,3 +155,13 @@ func (m *Mux) PrintRoutes(w io.Writer) {
 func (m *Mux) RouteList() []string {
 	return m.routes.All()
 }
+
+func copyMW(a []func(http.Handler) http.Handler, b []func(http.Handler) http.Handler) []func(http.Handler) http.Handler {
+	if len(b) > 0 {
+		return slices.Concat(a, b)
+	}
+
+	mws := make([]func(http.Handler) http.Handler, len(a))
+	copy(mws, a)
+	return mws
+}

mux_test.go

@@ -153,16 +153,17 @@ func TestRouterGroup(t *testing.T) {
 func TestRouterResource(t *testing.T) {
 	r := New()
 
-	r.Resource("/users", func(res *Resource) {
+	r.Resource("/users",
-		res.Index(func(w http.ResponseWriter, r *http.Request) {
+		func(res *Resource) {
-			fmt.Fprint(w, "All users")
+			res.Index(func(w http.ResponseWriter, r *http.Request) {
-		})
+				fmt.Fprint(w, "All users")
+			})
 
-		res.View(func(w http.ResponseWriter, r *http.Request) {
+			res.View(func(w http.ResponseWriter, r *http.Request) {
-			id := r.PathValue("id")
+				id := r.PathValue("id")
-			fmt.Fprintf(w, "User %s", id)
+				fmt.Fprintf(w, "User %s", id)
+			})
 		})
-	})
 
 	ts := httptest.NewServer(r)
 	defer ts.Close()
@@ -255,7 +256,7 @@ func TestStack(t *testing.T) {
 	})
 
 	middlewares := []func(http.Handler) http.Handler{middleware1, middleware2}
-	stacked := stack(middlewares, handler)
+	stacked := stack(handler, middlewares)
 
 	w := httptest.NewRecorder()
 	r := httptest.NewRequest(http.MethodGet, "/", nil)

resource.go

@@ -21,7 +21,7 @@ type Resource struct {
 //   - PUT  /pattern/:id			update a resource
 //   - PATCH  /pattern/:id		partial update a resource
 //   - DELETE /resource/:id		delete a resource
-func (m *Mux) Resource(pattern string, fn func(res *Resource)) {
+func (m *Mux) Resource(pattern string, fn func(res *Resource), mw ...func(http.Handler) http.Handler) {
 	if m == nil {
 		panic("mux: Resource() called on nil")
 	}
@@ -34,14 +34,10 @@ func (m *Mux) Resource(pattern string, fn func(res *Resource)) {
 		panic("mux: Resource() requires callback")
 	}
 
-	// Copy root middlewares.
-	mws := make([]func(http.Handler) http.Handler, len(m.middlewares))
-	copy(mws, m.middlewares)
-
 	fn(&Resource{
 		mux:         m.mux,
 		pattern:     pattern,
-		middlewares: mws,
+		middlewares: copyMW(m.middlewares, mw),
 		routes:      m.routes,
 	})
 }
@@ -125,7 +121,7 @@ func (res *Resource) handlerFunc(method, pattern string, h http.HandlerFunc) {
 	}
 
 	path := fmt.Sprintf("%s %s", method, pattern)
-	res.mux.Handle(path, stack(res.middlewares, h))
+	res.mux.Handle(path, stack(h, res.middlewares))
 }
 
 // Use will register middleware(s) on Router stack.

stack.go

@@ -3,7 +3,7 @@ package mux
 import "net/http"
 
 // stack middlewares(http handler) in order they are passed (FIFO)
-func stack(middlewares []func(http.Handler) http.Handler, endpoint http.Handler) http.Handler {
+func stack(endpoint http.Handler, middlewares []func(http.Handler) http.Handler) http.Handler {
 	// Return ahead of time if there aren't any middlewares for the chain
 	if len(middlewares) == 0 {
 		return endpoint