+A back-ported version of the same module from the 1.0.x branch, without the
+from os.path import join, normcase, abspath, sep
+def safe_join(base, *paths):
+ Joins one or more path components to the base path component intelligently.
+ Returns a normalized, absolute version of the final path.
+ The final path must be located inside of the base path component (otherwise
+ a ValueError is raised).
+ # We need to use normcase to ensure we don't false-negative on case
+ # insensitive operating systems (like Windows).
+ final_path = normcase(abspath(join(base, *paths)))
+ base_path = normcase(abspath(base))
+ base_path_len = len(base_path)
+ # Ensure final_path starts with base_path and that the next character after
+ # the final path is os.sep (or nothing, in which case final_path must be
+ if not final_path.startswith(base_path) \
+ or final_path[base_path_len:base_path_len+1] not in ('', sep):
+ raise ValueError('the joined path is located outside of the base path'