Validating destination file paths kim kardashian officially dating kanye west

The question of "How do I test pathname validity and, for valid pathnames, the existence or writability of those paths? Both are interesting, and neither have received a genuinely satisfactory answer here... Before hurling our fragile meat suits into the python-riddled moshpits of pain, we should probably define what we mean by "pathname validity." What defines validity, exactly?

validating destination file paths-10validating destination file paths-67

root_dirname = root_dirname.rstrip(sep) sep # Test whether each path component split from this pathname is valid or # not, ignoring non-existent and non-readable path components.

for pathname_part in pathname.split(sep): try: os.lstat(root_dirname pathname_part) # If an OS-specific exception is raised, its error code # indicates whether this pathname is valid or not.

A pathname is syntactically correct under this definition if it complies with all syntactic requirements of the root filesystem.

By "pathname validity," we mean the syntactic correctness of a pathname with respect to the root filesystem of the current system – regardless of whether that path or parent directories thereof physically exist.

Malicious users may attempt to repeatedly validate pathnames residing on filesystems known to be stale or otherwise slow (e.g., NFS Samba shares); in that case, blindly statting incoming pathnames is liable to either eventually fail with connection timeouts or consume more time and resources than your feeble capacity to withstand unemployment.

import errno, os # Sadly, Python fails to provide the following magic number for us.

Unless this # is the case, this exception implies an ignorable kernel or # filesystem complaint (e.g., path not found or inaccessible).

# # Only the following exceptions indicate invalid pathnames: # # * Instances of the Windows-specific "Windows Error" class # defining the "winerror" attribute whose value is # "ERROR_INVALID_NAME".

_, pathname = splitdrive(pathname) # Directory guaranteed to exist.

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