import os import tempfile from os.path import abspath, dirname, join, normcase, sep from pathlib import Path from django.core.exceptions import SuspiciousFileOperation def safe_join(base, *paths): """ Join one or more path components to the base path component intelligently. Return a normalized, absolute version of the final path. Raise ValueError if the final path isn't located inside of the base path component. """ final_path = abspath(join(base, *paths)) base_path = abspath(base) # Ensure final_path starts with base_path (using normcase to ensure we # don't false-negative on case insensitive operating systems like Windows), # further, one of the following conditions must be true: # a) The next character is the path separator (to prevent conditions like # safe_join("/dir", "/../d")) # b) The final path must be the same as the base path. # c) The base path must be the most root path (meaning either "/" or "C:\\") if ( not normcase(final_path).startswith(normcase(base_path + sep)) and normcase(final_path) != normcase(base_path) and dirname(normcase(base_path)) != normcase(base_path) ): raise SuspiciousFileOperation( "The joined path ({}) is located outside of the base path " "component ({})".format(final_path, base_path) ) return final_path def symlinks_supported(): """ Return whether or not creating symlinks are supported in the host platform and/or if they are allowed to be created (e.g. on Windows it requires admin permissions). """ with tempfile.TemporaryDirectory() as temp_dir: original_path = os.path.join(temp_dir, "original") symlink_path = os.path.join(temp_dir, "symlink") os.makedirs(original_path) try: os.symlink(original_path, symlink_path) supported = True except (OSError, NotImplementedError): supported = False return supported def to_path(value): """Convert value to a pathlib.Path instance, if not already a Path.""" if isinstance(value, Path): return value elif not isinstance(value, str): raise TypeError("Invalid path type: %s" % type(value).__name__) return Path(value)