I'm able to get the value of the file:
url = sharepoint_app_url + "_api/web/GetFileByServerRelativeUrl('" + file_path + "')/$value"
However when I want to get the versions or a specific version I get the 403 forbidden
url1 = sharepoint_app_url + "_api/web/GetFileByServerRelativeUrl('" + file_path + "')/Versions"