| import os |
| from os.path import join, normcase, normpath, abspath, isabs, sep |
| from django.utils.encoding import force_unicode |
| |
| # Define our own abspath function that can handle joining |
| # unicode paths to a current working directory that has non-ASCII |
| # characters in it. This isn't necessary on Windows since the |
| # Windows version of abspath handles this correctly. The Windows |
| # abspath also handles drive letters differently than the pure |
| # Python implementation, so it's best not to replace it. |
| if os.name == 'nt': |
| abspathu = abspath |
| else: |
| def abspathu(path): |
| """ |
| Version of os.path.abspath that uses the unicode representation |
| of the current working directory, thus avoiding a UnicodeDecodeError |
| in join when the cwd has non-ASCII characters. |
| """ |
| if not isabs(path): |
| path = join(os.getcwdu(), path) |
| return normpath(path) |
| |
| 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). |
| base = force_unicode(base) |
| paths = [force_unicode(p) for p in paths] |
| final_path = normcase(abspathu(join(base, *paths))) |
| base_path = normcase(abspathu(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 |
| # equal to base_path). |
| 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 (%s) is located outside of the base ' |
| 'path component (%s)' % (final_path, base_path)) |
| return final_path |
