Closes #261

Signed-off-by: Vishal Rana <vr@labstack.com>

echo.go

@@ -34,6 +34,7 @@ type (
 		renderer                Renderer
 		pool                    sync.Pool
 		debug                   bool
+		hook                    http.HandlerFunc
 		// stripTrailingSlash      bool
 		router *Router
 	}
@@ -261,6 +262,13 @@ func (e *Echo) Debug() bool {
 	return e.debug
 }
 
+// Hook registers a callback which is invoked from `Echo#ServerHTTP` as the first
+// statement. Hook is useful if you want to modify response/response objects even
+// before it hits the router or any middleware.
+func (e *Echo) Hook(h http.HandlerFunc) {
+	e.hook = h
+}
+
 // StripTrailingSlash enables removing trailing slash from the request path.
 // func (e *Echo) StripTrailingSlash() {
 // 	e.stripTrailingSlash = true
@@ -463,6 +471,10 @@ func (e *Echo) Routes() []Route {
 
 // ServeHTTP implements `http.Handler` interface, which serves HTTP requests.
 func (e *Echo) ServeHTTP(w http.ResponseWriter, r *http.Request) {
+	if e.hook != nil {
+		e.hook(w, r)
+	}
+
 	c := e.pool.Get().(*Context)
 	h, e := e.router.Find(r.Method, r.URL.Path, c)
 	c.reset(r, w, e)

echo_test.go

@@ -406,14 +406,23 @@ func TestEchoServer(t *testing.T) {
 	assert.IsType(t, &http.Server{}, s)
 }
 
-// func TestStripTrailingSlash(t *testing.T) {
+func TestEchoHook(t *testing.T) {
-// 	e := New()
+	e := New()
-// 	e.StripTrailingSlash()
+	e.Get("/test", func(c *Context) error {
-// 	r, _ := http.NewRequest(GET, "/users/", nil)
+		return c.NoContent(http.StatusNoContent)
-// 	w := httptest.NewRecorder()
+	})
-// 	e.ServeHTTP(w, r)
+	e.Hook(func(w http.ResponseWriter, r *http.Request) {
-// 	assert.Equal(t, http.StatusNotFound, w.Code)
+		path := r.URL.Path
-// }
+		l := len(path) - 1
+		if path != "/" && path[l] == '/' {
+			r.URL.Path = path[:l]
+		}
+	})
+	r, _ := http.NewRequest(GET, "/test/", nil)
+	w := httptest.NewRecorder()
+	e.ServeHTTP(w, r)
+	assert.Equal(t, r.URL.Path, "/test")
+}
 
 func testMethod(t *testing.T, method, path string, e *Echo) {
 	m := fmt.Sprintf("%c%s", method[0], strings.ToLower(method[1:]))

router.go

@@ -271,14 +271,6 @@ func (r *Router) Find(method, path string, ctx *Context) (h HandlerFunc, e *Echo
 	e = r.echo
 	cn := r.tree // Current node as root
 
-	// Strip trailing slash
-	// if r.echo.stripTrailingSlash {
-	// 	l := len(path) - 1
-	// 	if path != "/" && path[l] == '/' { // Issue #218
-	// 		path = path[:l]
-	// 	}
-	// }
-
 	var (
 		search = path
 		c      *node  // Child node

website/content/guide/customization.md

@@ -8,23 +8,43 @@ menu:
 
 ### HTTP error handler
 
-`Echo.SetHTTPErrorHandler(h HTTPErrorHandler)`
+`Echo#SetHTTPErrorHandler(h HTTPErrorHandler)`
 
-Registers a custom `Echo.HTTPErrorHandler`.
+Registers a custom `Echo#HTTPErrorHandler`.
 
 Default handler rules:
 
-- If error is of type `Echo.HTTPError` it sends HTTP response with status code `HTTPError.Code`
+- If error is of type `Echo#HTTPError` it sends HTTP response with status code `HTTPError.Code`
 and message `HTTPError.Message`.
 - Else it sends `500 - Internal Server Error`.
 - If debug mode is enabled, it uses `error.Error()` as status message.
 
 ### Debug
 
-`Echo.SetDebug(on bool)`
+`Echo#SetDebug(on bool)`
 
 Enables/disables debug mode.
 
 ### Disable colored log
 
-`Echo.DisableColoredLog()`
+`Echo#DisableColoredLog()`
+
+### Hook
+
+`Echo#Hook(http.HandlerFunc)`
+
+Hook registers a callback which is invoked from `Echo#ServerHTTP` as the first
+statement. Hook is useful if you want to modify response/response objects even
+before it hits the router or any middleware.
+
+For example, the following hook strips the trailing slash from the request path.
+
+```go
+e.Hook(func(w http.ResponseWriter, r *http.Request) {
+    path := r.URL.Path
+    l := len(path) - 1
+    if path != "/" && path[l] == '/' {
+        r.URL.Path = path[:l]
+    }
+})
+```