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| -rw-r--r-- | django/utils/_os.py | 28 |
1 files changed, 28 insertions, 0 deletions
diff --git a/django/utils/_os.py b/django/utils/_os.py new file mode 100644 index 0000000000..2bb8fc31a7 --- /dev/null +++ b/django/utils/_os.py @@ -0,0 +1,28 @@ +""" +A back-ported version of the same module from the 1.0.x branch, without the +unicode support. +""" + +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 + # 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 is located outside of the base path' + ' component') + return final_path |