tempfile Question

[John Machin]

On 7/06/2006 7:50 AM, Gregory Piñero wrote:
> Hey group,
> 
> I have a command line tool that I want to be able to call from a
> Python script.  The problem is that this tool only writes to a file.
> 
> So my solution is to give the tool a temporary file to write to and
> then have Python read that file.  I figure that's the safest way to
> deal with this sort of thing.  (But I'm open to better methods).
> 
> Here's my code so far, could anyone tell me the proper way to use
> tempfile.  This code won't let the tool write to the file because
> Python has it locked.  But I'm worried that if I close the file then
> windows might take it away?  I have no idea.

Me neither, not having faced this situation before. To acquire an idea, 
I'd Read The Fantastic Manual:
(my comments enclosed in [])
"""
TemporaryFile( [mode='w+b'[, bufsize=-1[, suffix[, prefix[, dir]]]]])

Return a file (or file-like) object that can be used as a temporary 
storage area. The file is created using mkstemp. It will be destroyed as 
soon as it is closed (including an implicit close when the object is 
garbage collected).[That seems to answer one question] Under Unix, the 
directory entry for the file is removed immediately after the file is 
created. Other platforms do not support this; your code should not rely 
on a temporary file created using this function having or not having a 
visible name in the file system.
The mode parameter defaults to 'w+b' so that the file created can be 
read and written without being closed. Binary mode is used so that it 
behaves consistently on all platforms without regard for the data that 
is stored. bufsize defaults to -1, meaning that the operating system 
default is used.

The dir, prefix and suffix parameters are passed to mkstemp().


NamedTemporaryFile( [mode='w+b'[, bufsize=-1[, suffix[, prefix[, dir]]]]])

This function operates exactly as TemporaryFile() does, except that the 
file is guaranteed to have a visible name in the file system (on Unix, 
the directory entry is not unlinked). That name can be retrieved from 
the name member of the file object. Whether the name can be used to open 
the file a second time, while the named temporary file is still open, 
varies across platforms (it can be so used on Unix; it cannot on Windows 
NT or later [That seems to answer the other question]). New in version 2.3.
"""

So I'd be thinking about using the (deprecated) mktemp() instead, 
perhaps trying to cut down the chance of conflicts by (a) using a prefix 
  e.g. "pdf2txttmp" and/or (b) using a dir of "." -- then asking the 
cognoscenti what are the drawbacks of this approach.

HTH,
John