Copy a file with a too long path to another directory in Python

Question

I am trying to copy files on Windows with Python 2.7, but sometimes this fails.

shutil.copyfile(copy_file, dest_file)

I get the following IOError:

[Errno 2] No such file or directory

But the file does exist! The problem is that the path of the file is too long. (> 255 characters)

How do I copy these files? It isn't a problem to open them in other applications.

To create a file with a too long path, create a file with an as long as possible file name and move the containing folder deeper down a tree structure.

I've been trying some of these methods without success: http://timgolden.me.uk/python/win32_how_do_i/copy-a-file.html

Answer 1

I wasn't sure about the 255 char limit so I stumbled on this post. There I found a working answer: adding \\?\ before the path.

shutil.copyfile("\\\\?\\" + copy_file, dest_file)

edit: I've found that working with long paths causes issues on Windows. Another trick I use is to just shorten the paths:

import win32api
path = win32api.GetShortPathName(path)

Answer 2

Thanks for the answer Gfy. I have a requirement to use relative paths. The \\?\ can't be added successfully to a relative path, so it's necessary to convert to an absolute path first (run from desktop):

import os

def clean_path(path):
    path = path.replace('/',os.sep).replace('\\',os.sep)
    if os.sep == '\\' and '\\\\?\\' not in path:
        # fix for Windows 260 char limit
        relative_levels = len([directory for directory in path.split(os.sep) if directory == '..'])
        cwd = [directory for directory in os.getcwd().split(os.sep)] if ':' not in path else []
        path = '\\\\?\\' + os.sep.join(cwd[:len(cwd)-relative_levels]\
                         + [directory for directory in path.split(os.sep) if directory!=''][relative_levels:])
    return path

clean_path('samples')
\\?\C:\Users\Username\Desktop\samples
clean_path('\samples')
\\?\C:\Users\Username\Desktop\samples
clean_path('..\samples')
\\?\C:\Users\Username\samples
clean_path('..\..\samples')
\\?\C:\Users\samples
clean_path('C:\Users\Username\Dropbox')
\\?\C:\Users\Username\Dropbox