Fix subrouter group when ServeFiles

Author: Sergio Andres Virviescas Santana

router.go

@@ -291,6 +291,16 @@ func (r *Router) ServeFiles(path string, rootPath string) {
 	if len(path) < 10 || path[len(path)-10:] != "/*filepath" {
 		panic("path must end with /*filepath in path '" + path + "'")
 	}
+
+	if r.beginPath != "/" {
+		path = r.beginPath + path
+	}
+
+	if r.parent != nil {
+		r.parent.ServeFiles(path, rootPath)
+		return
+	}
+
 	prefix := path[:len(path)-10]
 
 	fileHandler := fasthttp.FSHandler(rootPath, strings.Count(prefix, "/"))

router_test.go

@@ -370,6 +370,8 @@ func TestRouterGroup(t *testing.T) {
 		barHit = true
 		ctx.SetStatusCode(fasthttp.StatusOK)
 	})
+	r6.ServeFiles("/static/*filepath", "./")
+
 	s := &fasthttp.Server{
 		Handler: r1.Handler,
 	}
@@ -499,6 +501,27 @@ func TestRouterGroup(t *testing.T) {
 		t.FailNow()
 	}
 
+	// testing multiple sub-router group - r6 (grouped from r5) to serve files
+	rw.r.WriteString("GET /moo/foo/foo/static/router.go HTTP/1.1\r\n\r\n")
+	go func() {
+		ch <- s.ServeConn(rw)
+	}()
+	select {
+	case err := <-ch:
+		if err != nil {
+			t.Fatalf("return error %s", err)
+		}
+	case <-time.After(100 * time.Millisecond):
+		t.Fatalf("timeout")
+	}
+	if err := resp.Read(br); err != nil {
+		t.Fatalf("Unexpected error when reading response: %s", err)
+	}
+	if !(resp.Header.StatusCode() == fasthttp.StatusOK && barHit) {
+		t.Errorf("Chained routing failed with subrouter grouping.")
+		t.FailNow()
+	}
+
 	rw.r.WriteString("POST /qax HTTP/1.1\r\n\r\n")
 	go func() {
 		ch <- s.ServeConn(rw)