fix index.html issue (#8)

/index.html will automatic redirect to /
refer:https://github.com/golang/go/blob/master/src/net/http/fs.go#L541

static.go

@@ -1,14 +1,15 @@
 package static
 
 import (
+	"github.com/gin-gonic/gin"
 	"net/http"
 	"os"
 	"path"
 	"strings"
-
-	"github.com/gin-gonic/gin"
 )
 
+const INDEX = "index.html"
+
 type ServeFileSystem interface {
 	http.FileSystem
 	Exists(prefix string, path string) bool
@@ -35,9 +36,15 @@ func (l *localFileSystem) Exists(prefix string, filepath string) bool {
 		if err != nil {
 			return false
 		}
-		if !l.indexes && stats.IsDir() {
+		if stats.IsDir() {
+			if !l.indexes {
+				index := path.Join(name, INDEX)
+				_, err := os.Stat(index)
+				if err != nil {
 					return false
 				}
+			}
+		}
 		return true
 	}
 	return false

static_test.go

@@ -1,15 +1,15 @@
 package static
 
 import (
+	"github.com/gin-gonic/gin"
+	"github.com/stretchr/testify/assert"
 	"io/ioutil"
 	"net/http"
 	"net/http/httptest"
 	"os"
+	"path"
 	"path/filepath"
 	"testing"
-
-	"github.com/gin-gonic/gin"
-	"github.com/stretchr/testify/assert"
 )
 
 func performRequest(r http.Handler, method, path string) *httptest.ResponseRecorder {
@@ -84,3 +84,50 @@ func TestEmptyDirectory(t *testing.T) {
 	assert.Equal(t, w.Code, 200)
 	assert.Equal(t, w.Body.String(), "Gin Web Framework")
 }
+
+func TestIndex(t *testing.T) {
+	// SETUP file
+	testRoot, _ := os.Getwd()
+	f, err := os.Create(path.Join(testRoot, "index.html"))
+	if err != nil {
+		t.Error(err)
+	}
+	defer os.Remove(f.Name())
+	f.WriteString("index")
+	f.Close()
+
+	dir, filename := filepath.Split(f.Name())
+
+	router := gin.New()
+	router.Use(ServeRoot("/", dir))
+
+	w := performRequest(router, "GET", "/"+filename)
+	assert.Equal(t, w.Code, 301)
+
+	w = performRequest(router, "GET", "/")
+	assert.Equal(t, w.Code, 200)
+	assert.Equal(t, w.Body.String(), "index")
+}
+
+func TestListIndex(t *testing.T) {
+	// SETUP file
+	testRoot, _ := os.Getwd()
+	f, err := ioutil.TempFile(testRoot, "")
+	if err != nil {
+		t.Error(err)
+	}
+	defer os.Remove(f.Name())
+	f.WriteString("Gin Web Framework")
+	f.Close()
+
+	dir, filename := filepath.Split(f.Name())
+	router := gin.New()
+	router.Use(Serve("/", LocalFile(dir, true)))
+
+	w := performRequest(router, "GET", "/"+filename)
+	assert.Equal(t, w.Code, 200)
+	assert.Equal(t, w.Body.String(), "Gin Web Framework")
+
+	w = performRequest(router, "GET", "/")
+	assert.Contains(t, w.Body.String(), `<a href="`+filename)
+}