Reorganize file util functionality (#7848)

* reorganize file util functionality

* fix api test compilation

* fix rebase issue

api/file.go

@@ -95,7 +95,7 @@ func getFile(c *Context, w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
-	if data, err := utils.ReadFile(info.Path); err != nil {
+	if data, err := c.App.ReadFile(info.Path); err != nil {
 		c.Err = err
 		c.Err.StatusCode = http.StatusNotFound
 	} else if err := writeFileResponse(info.Name, info.MimeType, data, w, r); err != nil {
@@ -116,7 +116,7 @@ func getFileThumbnail(c *Context, w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
-	if data, err := utils.ReadFile(info.ThumbnailPath); err != nil {
+	if data, err := c.App.ReadFile(info.ThumbnailPath); err != nil {
 		c.Err = err
 		c.Err.StatusCode = http.StatusNotFound
 	} else if err := writeFileResponse(info.Name, THUMBNAIL_IMAGE_TYPE, data, w, r); err != nil {
@@ -137,7 +137,7 @@ func getFilePreview(c *Context, w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
-	if data, err := utils.ReadFile(info.PreviewPath); err != nil {
+	if data, err := c.App.ReadFile(info.PreviewPath); err != nil {
 		c.Err = err
 		c.Err.StatusCode = http.StatusNotFound
 	} else if err := writeFileResponse(info.Name, PREVIEW_IMAGE_TYPE, data, w, r); err != nil {
@@ -186,7 +186,7 @@ func getPublicFile(c *Context, w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
-	if data, err := utils.ReadFile(info.Path); err != nil {
+	if data, err := c.App.ReadFile(info.Path); err != nil {
 		c.Err = err
 		c.Err.StatusCode = http.StatusNotFound
 	} else if err := writeFileResponse(info.Name, info.MimeType, data, w, r); err != nil {
@@ -277,7 +277,7 @@ func getPublicFileOld(c *Context, w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
-	if data, err := utils.ReadFile(info.Path); err != nil {
+	if data, err := c.App.ReadFile(info.Path); err != nil {
 		c.Err = err
 		c.Err.StatusCode = http.StatusNotFound
 	} else if err := writeFileResponse(info.Name, info.MimeType, data, w, r); err != nil {