[Tutor] Permissions Error

[Tim Golden]

On 27/03/2012 05:00, Michael Lewis wrote:
> Traceback (most recent call last):
>    File "C:\Python27\Utilities\copyfiles.py", line 47, in <module>
>      copyfiles(srcdir, dstdir)
>    File "C:\Python27\Utilities\copyfiles.py", line 42, in copyfiles
>      shutil.copy(srcfile, dstfile)
>    File "C:\Python27\lib\shutil.py", line 116, in copy
>      copyfile(src, dst)
>    File "C:\Python27\lib\shutil.py", line 81, in copyfile
>      with open(src, 'rb') as fsrc:
> IOError: [Errno 13] Permission denied: 'C:\\Users\\Chief
> Ninja\\Pictures\\testdir'

It's not 100% clear what's going on, but it looks as though
you've passed along paths whicih result in shutil trying
to open a *directory* for reading -- which it won't be able
to do. (It is, in fact, possible to get a file handle to a directory
on Windows but you don't want to do that and shutil doesn't
know how).

>
> I've noticed that the code runs if I use shutil.copyfiles instead of
> shutil.copy. Do you know why?

Assuming my premise above, it would be because it special-cases
directories passed as parameter. (I haven't actually looked at
the code to check).

With this kind of problem the most helpful thing you can do for
yourself -- and for us if you can't resolve it yourself -- is
to pull yourself out of the depths of your copy/copyfiles
architecture and to try to do a simple:

open ("c:/path/to/file.txt", "rb")

If that succeeds then obviuosly there's no permissions issue as
such. If it fails (with an access error) then we're onto something.
If it succeeds then, probably your more complex copyfiles code
is doing something you don't think it's doing. Start chucking
out print () statements or logging or something so you know
*exactly* where the paths are pointing to which you're passing
into the shutil or other stdlib functions.

Hopefully all this will make it clearer what's going on. Full marks
for posting your code -- that does help. But you'll do better if
you post a *minimal* code example, and preferably a self-complete
one.

TJG