Implementation endpoint of APIv4: GET /files/{file_id}/thumbnail (#5553)

* APIv4: GET /files/{file_id}/thumbnail

* added delay time

1 files changed, 33 insertions, 0 deletions

diff --git a/api4/file.go b/api4/file.go
index b486fc220..924f7e416 100644
--- a/api4/file.go
+++ b/api4/file.go
@@ -23,6 +23,7 @@ func InitFile() {
 
 	BaseRoutes.Files.Handle("", ApiSessionRequired(uploadFile)).Methods("POST")
 	BaseRoutes.File.Handle("", ApiSessionRequired(getFile)).Methods("GET")
+	BaseRoutes.File.Handle("/thumbnail", ApiSessionRequired(getFileThumbnail)).Methods("GET")
 
 }
 
@@ -92,6 +93,38 @@ func getFile(c *Context, w http.ResponseWriter, r *http.Request) {
 	}
 }
 
+func getFileThumbnail(c *Context, w http.ResponseWriter, r *http.Request) {
+	c.RequireFileId()
+	if c.Err != nil {
+		return
+	}
+
+	info, err := app.GetFileInfo(c.Params.FileId)
+	if err != nil {
+		c.Err = err
+		return
+	}
+
+	if info.CreatorId != c.Session.UserId && !app.SessionHasPermissionToChannelByPost(c.Session, info.PostId, model.PERMISSION_READ_CHANNEL) {
+		c.SetPermissionError(model.PERMISSION_READ_CHANNEL)
+		return
+	}
+
+	if info.ThumbnailPath == "" {
+		c.Err = model.NewLocAppError("getFileThumbnail", "api.file.get_file_thumbnail.no_thumbnail.app_error", nil, "file_id="+info.Id)
+		c.Err.StatusCode = http.StatusBadRequest
+		return
+	}
+
+	if data, err := app.ReadFile(info.ThumbnailPath); err != nil {
+		c.Err = err
+		c.Err.StatusCode = http.StatusNotFound
+	} else if err := writeFileResponse(info.Name, info.MimeType, data, w, r); err != nil {
+		c.Err = err
+		return
+	}
+}
+
 func writeFileResponse(filename string, contentType string, bytes []byte, w http.ResponseWriter, r *http.Request) *model.AppError {
 	w.Header().Set("Cache-Control", "max-age=2592000, public")
 	w.Header().Set("Content-Length", strconv.Itoa(len(bytes)))