[Tutor] opening a file directly from memory

[mjekl at iol.pt]

davea at ieee.org wrote:
mjekl at iol.pt wrote:
<div class="moz-text-flowed" style="font-family: -moz-fixed">I'm  
wondering if I must
save a file to memory before opening it. By opening I mean displaying  
it to the user.

I have a BLOB field in a db and I have managed to read the blob into a binary
fileobject. I've also managed to write it to disk and then I open it  
by doubleclicking
on it. But I was wondering:

1. How to open the file directly from code (and not by double clicking):
I'm aware of os.startfile on Win by I'm on a Mac now, so I rather have  
a cross-platform
way of accomplishing this.

2. If there is any Python module that takes care of saving and  
cleaning temp files in
an OS transparent way?

Txs,
Miguel
You don't say what this binary data is.  Is there a specific program  
that should be
launched to "display it to the user" ?  Or do you have to keep this general?

If you know what the necessary program is, you could use subprocess  
module to launch it.
But I don't know enough about the Mac to know how to do the Mac equivalent of
os.startfile

As for avoiding the use of a file, that depends entirely on the program you're
launching.  Some programs can be told to get their data from stdin.   
If that's the case,
there's a way to provide stdin directly from Python, using subprocess.

As for temporary files, consider tempfile module. I haven't used it,  
but it looks
promising. HTH,
DaveA
I know what the binary data is from the database. Typically it would  
be some file the OS
knows how to open.
Chiefly I'm trying to avoid making the user save the file on some  
location and then go
and double click it to open it. This makes no sense, since the user  
has already made the
decision to open the file.

Txs Dave,
Miguel

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