sanitize_filename.py

"""
MIT License

Copyright (c) 2020 J++ Stockholm

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.
"""
# from https://gitlab.com/jplusplus/sanitize-filename/-/blob/master/sanitize_filename/sanitize_filename.py

"""A permissive filename sanitizer."""
import unicodedata
import re


def sanitize(filename):
    """Return a fairly safe version of the filename.

    We don't limit ourselves to ascii, because we want to keep municipality
    names, etc, but we do want to get rid of anything potentially harmful,
    and make sure we do not exceed Windows filename length limits.
    Hence a less safe blacklist, rather than a whitelist.
    """
    blacklist = ["\\", "/", ":", "*", "?", "\"", "<", ">", "|", "\0"]
    reserved = [
        "CON", "PRN", "AUX", "NUL", "COM1", "COM2", "COM3", "COM4", "COM5",
        "COM6", "COM7", "COM8", "COM9", "LPT1", "LPT2", "LPT3", "LPT4", "LPT5",
        "LPT6", "LPT7", "LPT8", "LPT9",
    ]  # Reserved words on Windows
    filename = "".join(c for c in filename if c not in blacklist)
    # Remove all charcters below code point 32
    filename = "".join(c for c in filename if 31 < ord(c))
    filename = unicodedata.normalize("NFKD", filename)
    filename = filename.rstrip(". ")  # Windows does not allow these at end
    filename = filename.strip()
    if all([x == "." for x in filename]):
        filename = "__" + filename
    if filename in reserved:
        filename = "__" + filename
    if len(filename) == 0:
        filename = "__"
    if len(filename) > 255:
        parts = re.split(r"/|\\", filename)[-1].split(".")
        if len(parts) > 1:
            ext = "." + parts.pop()
            filename = filename[:-len(ext)]
        else:
            ext = ""
        if filename == "":
            filename = "__"
        if len(ext) > 254:
            ext = ext[254:]
        maxl = 255 - len(ext)
        filename = filename[:maxl]
        filename = filename + ext
        # Re-check last character (if there was no extension)
        filename = filename.rstrip(". ")
        if len(filename) == 0:
            filename = "__"
    return filename