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Re: Make a unique filesystem path, without creating the file

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Gregory Ewing wrote:

> Ben Finney wrote:
>> One valid filesystem path each time it's accessed. That is, behaviour
>> equivalent to ‘tempfile.mktemp’.
>> 
>> My question is because the standard library clearly has this useful
>> functionality implemented, but simultaneously warns strongly against its
>> use.
> 
> But it *doesn't*,

Yes, it does.

> if your requirement is truly to not touch the filesystem at all, because
> tempfile.mktemp() *reads* the file system to make sure the name it's
> returning isn't in use.

But there is a race condition occurring between the moment that the 
filesystem has been read and is being written to by another user.  Hence the 
deprecation in favor of tempfile.mkstemp() which also *creates* the file 
instead, and the warning about the security hole if tempfile.mktemp() is 
used anyway.

You can use tempfile.mktemp() only as long as it is irrelevant if a file 
with that name already exists, or exists later but was not created by you.

-- 
PointedEars

Twitter: @PointedEars2
Please do not cc me. / Bitte keine Kopien per E-Mail.

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Re: Make a unique filesystem path, without creating the file Ben Finney <ben+python@benfinney.id.au> - 2016-02-15 11:08 +1100
  Re: Make a unique filesystem path, without creating the file Dan Sommers <dan@tombstonezero.net> - 2016-02-15 01:07 +0000
    Re: Make a unique filesystem path, without creating the file Ben Finney <ben+python@benfinney.id.au> - 2016-02-15 12:19 +1100
      Re: Make a unique filesystem path, without creating the file Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2016-02-15 15:54 +1100
        Re: Make a unique filesystem path, without creating the file Ben Finney <ben+python@benfinney.id.au> - 2016-02-15 16:25 +1100
        Re: Make a unique filesystem path, without creating the file Rick Johnson <rantingrickjohnson@gmail.com> - 2016-02-15 18:26 -0800
      Re: Make a unique filesystem path, without creating the file Gregory Ewing <greg.ewing@canterbury.ac.nz> - 2016-02-15 21:00 +1300
        Re: Make a unique filesystem path, without creating the file Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2016-02-16 01:18 +0100
      Re: Make a unique filesystem path, without creating the file Grant Edwards <invalid@invalid.invalid> - 2016-02-15 15:49 +0000
  Re: Make a unique filesystem path, without creating the file Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2016-02-15 15:06 +1100
    Re: Make a unique filesystem path, without creating the file Ben Finney <ben+python@benfinney.id.au> - 2016-02-15 15:28 +1100
      Re: Make a unique filesystem path, without creating the file Gregory Ewing <greg.ewing@canterbury.ac.nz> - 2016-02-15 21:11 +1300
      Re: Make a unique filesystem path, without creating the file Nobody <nobody@nowhere.invalid> - 2016-02-16 02:14 +0000
    Re: Make a unique filesystem path, without creating the file "Martin A. Brown" <martin@linux-ip.net> - 2016-02-14 20:48 -0800

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