return proper content type instead of image/*

backend/app/rest/api/rest_private_test.go

@@ -870,25 +870,25 @@ func TestRest_SavePictureCtrl(t *testing.T) {
 	body, err := ioutil.ReadAll(resp.Body)
 	require.NoError(t, err)
 	assert.Equal(t, 1462, len(body))
-	assert.Equal(t, "image/*", resp.Header.Get("Content-Type"))
+	assert.Equal(t, "image/png", resp.Header.Get("Content-Type"))
 
 	id = savePic("picture.gif")
 	resp, err = http.Get(fmt.Sprintf("%s/api/v1/picture/%s", ts.URL, id))
 	require.NoError(t, err)
 	assert.Equal(t, 200, resp.StatusCode)
-	assert.Equal(t, "image/*", resp.Header.Get("Content-Type"))
+	assert.Equal(t, "image/png", resp.Header.Get("Content-Type"))
 
 	id = savePic("picture.jpg")
 	resp, err = http.Get(fmt.Sprintf("%s/api/v1/picture/%s", ts.URL, id))
 	require.NoError(t, err)
 	assert.Equal(t, 200, resp.StatusCode)
-	assert.Equal(t, "image/*", resp.Header.Get("Content-Type"))
+	assert.Equal(t, "image/png", resp.Header.Get("Content-Type"))
 
 	id = savePic("picture.blah")
 	resp, err = http.Get(fmt.Sprintf("%s/api/v1/picture/%s", ts.URL, id))
 	require.NoError(t, err)
 	assert.Equal(t, 200, resp.StatusCode)
-	assert.Equal(t, "image/*", resp.Header.Get("Content-Type"))
+	assert.Equal(t, "image/png", resp.Header.Get("Content-Type"))
 
 	resp, err = http.Get(fmt.Sprintf("%s/api/v1/picture/blah/pic.blah", ts.URL))
 	require.NoError(t, err)

backend/app/rest/api/rest_public.go

@@ -422,20 +422,6 @@ func (s *public) listCtrl(w http.ResponseWriter, r *http.Request) {
 
 // GET /picture/{user}/{id} - get picture
 func (s *public) loadPictureCtrl(w http.ResponseWriter, r *http.Request) {
-
-	imgContentType := func(img string) string {
-		img = strings.ToLower(img)
-		switch {
-		case strings.HasSuffix(img, ".png"):
-			return "image/png"
-		case strings.HasSuffix(img, ".jpg") || strings.HasSuffix(img, ".jpeg"):
-			return "image/jpeg"
-		case strings.HasSuffix(img, ".gif"):
-			return "image/gif"
-		}
-		return "image/*"
-	}
-
 	id := chi.URLParam(r, "user") + "/" + chi.URLParam(r, "id")
 	img, err := s.imageService.Load(id)
 	if err != nil {
@@ -453,7 +439,7 @@ func (s *public) loadPictureCtrl(w http.ResponseWriter, r *http.Request) {
 		}
 	}
 
-	w.Header().Set("Content-Type", imgContentType(id))
+	w.Header().Set("Content-Type", s.imageService.ImgContentType(img))
 	w.Header().Set("Content-Length", strconv.Itoa(len(img)))
 	w.WriteHeader(http.StatusOK)
 	if _, err = io.Copy(w, bytes.NewReader(img)); err != nil {

backend/app/rest/proxy/image.go

@@ -131,7 +131,7 @@ func (p Image) Handler(w http.ResponseWriter, r *http.Request) {
 		}
 	}
 
-	w.Header().Add("Content-Type", "image/*")
+	w.Header().Add("Content-Type", p.ImageService.ImgContentType(img))
 	_, err = io.Copy(w, bytes.NewReader(img))
 	if err != nil {
 		log.Printf("[WARN] can't copy image stream, %s", err)

backend/app/rest/proxy/image_test.go

@@ -109,7 +109,7 @@ func TestImage_Routes(t *testing.T) {
 	require.NoError(t, err)
 	assert.Equal(t, 200, resp.StatusCode)
 	assert.Equal(t, "1462", resp.Header["Content-Length"][0])
-	assert.Equal(t, "image/*", resp.Header["Content-Type"][0])
+	assert.Equal(t, "image/png", resp.Header["Content-Type"][0])
 
 	encodedImgURL = base64.URLEncoding.EncodeToString([]byte(httpSrv.URL + "/image/no-such-image.png"))
 	resp, err = http.Get(ts.URL + "/?src=" + encodedImgURL)
@@ -147,10 +147,10 @@ func TestImage_RoutesCachingImage(t *testing.T) {
 	require.Nil(t, err)
 	assert.Equal(t, 200, resp.StatusCode)
 	assert.Equal(t, "1462", resp.Header["Content-Length"][0])
-	assert.Equal(t, "image/*", resp.Header["Content-Type"][0])
+	assert.Equal(t, "image/png", resp.Header["Content-Type"][0])
 
 	imageStore.AssertCalled(t, "Load", mock.Anything)
-	imageStore.AssertCalled(t, "SaveWithID", "cached_images/4b84b15bff6ee5796152495a230e45e3d7e947d9-"+sha1Str(imgURL), mock.Anything)
+	imageStore.AssertCalled(t, "SaveWithID", "cached_images/4b84b15bff6ee5796152495a230e45e3d7e947d9-"+sha1Str(imgURL), gopherPNGBytes())
 	imageStore.AssertCalled(t, "Commit", mock.Anything)
 }
 
@@ -178,7 +178,8 @@ func TestImage_RoutesUsingCachedImage(t *testing.T) {
 	require.Nil(t, err)
 	assert.Equal(t, 200, resp.StatusCode)
 	assert.Equal(t, "256", resp.Header["Content-Length"][0])
-	assert.Equal(t, "image/*", resp.Header["Content-Type"][0])
+	assert.Equal(t, "text/plain; charset=utf-8", resp.Header["Content-Type"][0],
+		"if you save text you receive text/plain in response, that's only fair option you got")
 
 	imageStore.AssertCalled(t, "Load", mock.Anything)
 }

backend/app/store/image/image.go

@@ -201,6 +201,15 @@ func (s *Service) SaveWithID(id string, r io.Reader) (string, error) {
 	return s.store.SaveWithID(id, img)
 }
 
+func (s *Service) ImgContentType(img []byte) string {
+	contentType := http.DetectContentType(img)
+	if contentType == "application/octet-stream" {
+		// replace generic fallback with one which make sense in our scenario
+		return "image/*"
+	}
+	return contentType
+}
+
 // prepareImage calls readAndValidateImage and resize on provided image.
 func (s *Service) prepareImage(r io.Reader) ([]byte, error) {
 	data, err := readAndValidateImage(r, s.MaxSize)