Can't write to a directory made w/ os.makedirs
MRAB
python at mrabarnett.plus.com
Sun Jan 1 22:43:43 EST 2012
On 02/01/2012 03:14, David Goldsmith wrote:
> On Jan 1, 7:05 am, Tim Golden<m... at timgolden.me.uk> wrote:
>> On 01/01/2012 12:05, David Goldsmith wrote:
>> >> ie can the Python process creating the directories,
>> >
>> > Yes.
>> >
>> >> and a subprocess called from it create a simple file?
>> >
>> > No.
>> >
>> >> Depending on where you are in the filesystem, it may indeed
>> >> be necessary to be running as administrator. But don't try
>> >> to crack every security nut with an elevated sledgehammer.
>> >
>> > If you mean running as admin., those were my sentiments exactly. So,
>> > there isn't something specific I should be doing to assure that my
>> > subproceses can write to directories?
>>
>> In the general case, no. By default, a subprocess will have
>> the same security context as its parent. The exception is
>> where the parent (the Python processing invoking subprocess.call
>> in this example) is already impersonating a different user;
>> in that case, the subprocess will inherit its grandparent's
>> context.
>>
>> But unless you're doing something very deliberate here then
>> I doubt if that's biting you.
>>
>> Can I ask: are you absolutely certain that the processes
>> you're calling are doing what you think they are and failing
>> where you think they're failing?
>>
>> TJG
>
> I'm a mathematician: the only thing I'm absolutely certain of is
> nothing.
>
> Here's my script, in case that helps:
>
> import os
> import sys
> import stat
> import os.path as op
> import subprocess as sub
> from os import remove
> from os import listdir as ls
> from os import makedirs as mkdir
>
> def doFlac2Mp3(arg, d, fl):
> if '.flac' in [f[-5:] for f in fl]:
> newD = d.replace('FLACS', 'MP3s')
> mkdir(newD)
> for f in fl:
> if f[-5:]=='.flac':
> root = f.replace('.flac', '')
> cmd = ['"C:\\Program Files (x86)\\aTunes\\win_tools\
> \flac.exe" -d ' +
> '--output-prefix=' + newD + '\\', f]
> res = sub.call(cmd)#, env={'PATH': os.defpath})
> if not res:
> cmd = ['"C:\\Program Files (x86)\\aTunes\\win_tools
> \\lame.exe" -h',
> newD + root + '.wav', newD + root +
> '.mp3']
> res = sub.call(cmd)#, env={'PATH': os.defpath})
> if not res:
> rf = newD + root + '.wav'
> remove(rf)
>
> top=sys.argv[1]
> op.walk(top, doFlac2Mp3, None)
I think that if the command line should be something like:
"C:\Program Files (x86)\aTunes\win_tools\flac.exe" -d
--output-prefix=FOO\ BAR
then the cmd should be something like:
cmd = ['C:\\Program Files (x86)\\aTunes\\win_tools\\flac.exe', '-d',
'--output-prefix="' + newD + '\\"', f]
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