Function is_zipfile

Lib/zipfile/__init__.py:254–270

Quickly see if a file is a ZIP file by checking the magic number. The filename argument may be a file or file-like object too.

(filename)

    return False

def is_zipfile(filename):
    """Quickly see if a file is a ZIP file by checking the magic number.

    The filename argument may be a file or file-like object too.
    """
    result = False
    try:
        if hasattr(filename, "read"):
            pos = filename.tell()
            result = _check_zipfile(fp=filename)
            filename.seek(pos)
        else:
            with open(filename, "rb") as fp:
                result = _check_zipfile(fp)
    except (OSError, BadZipFile):
        pass
    return result

def _handle_prepended_data(endrec, debug=0):
    size_cd = endrec[_ECD_SIZE]             # bytes in central directory