static: handle If-None-Match for ETag. (#200)

static.go

@@ -178,8 +178,12 @@ func staticHandler(ctx *Context, log *log.Logger, opt StaticOptions) bool {
 	}
 
 	if opt.ETag {
-		tag := GenerateETag(string(fi.Size()), fi.Name(), fi.ModTime().UTC().Format(http.TimeFormat))
-		ctx.Resp.Header().Set("ETag", `"`+tag+`"`)
+		tag := `"` + GenerateETag(string(fi.Size()), fi.Name(), fi.ModTime().UTC().Format(http.TimeFormat)) + `"`
+		ctx.Resp.Header().Set("ETag", tag)
+		if ctx.Req.Header.Get("If-None-Match") == tag {
+			ctx.Resp.WriteHeader(http.StatusNotModified)
+			return true
+		}
 	}
 
 	http.ServeContent(ctx.Resp, ctx.Req.Request, file, fi.ModTime(), f)

static_test.go

@@ -176,8 +176,7 @@ func Test_Static_Options(t *testing.T) {
 	})
 
 	Convey("Serve static files with options expires", t, func() {
-		var buf bytes.Buffer
-		m := NewWithLogger(&buf)
+		m := New()
 		opt := StaticOptions{Expires: func() string { return "46" }}
 		m.Use(Static(currentRoot, opt))
 
@@ -190,8 +189,7 @@ func Test_Static_Options(t *testing.T) {
 	})
 
 	Convey("Serve static files with options ETag", t, func() {
-		var buf bytes.Buffer
-		m := NewWithLogger(&buf)
+		m := New()
 		opt := StaticOptions{ETag: true}
 		m.Use(Static(currentRoot, opt))
 
@@ -203,6 +201,26 @@ func Test_Static_Options(t *testing.T) {
 
 		So(resp.Header().Get("ETag"), ShouldEqual, `"`+tag+`"`)
 	})
+
+	Convey("Serve static files with ETag in If-None-Match", t, func() {
+		m := New()
+		opt := StaticOptions{ETag: true}
+		m.Use(Static(currentRoot, opt))
+
+		resp := httptest.NewRecorder()
+		req, err := http.NewRequest("GET", "http://localhost:4000/macaron.go", nil)
+		So(err, ShouldBeNil)
+		m.ServeHTTP(resp, req)
+		tag := GenerateETag(string(resp.Body.Len()), "macaron.go", resp.Header().Get("last-modified"))
+
+		// Second request with ETag in If-None-Match
+		resp = httptest.NewRecorder()
+		req.Header.Add("If-None-Match", `"`+tag+`"`)
+		m.ServeHTTP(resp, req)
+
+		So(resp.Code, ShouldEqual, http.StatusNotModified)
+		So(len(resp.Body.Bytes()), ShouldEqual, 0)
+	})
 }
 
 func Test_Static_Redirect(t *testing.T) {