Accessing external file output from script?

Platform: Windows
Python: 2.3
Python Skill: Reading, Learning, but still newbie.

Mission: My mission is writing a script that is triggered from my mail
server. The script will execute and download a file. The email that
triggered the message has a file size which is compared to the
downloaded file to make sure the bytes match. Once that is accomplished
there is a small program (.exe) that I can run against the file. The
..exe has two outputs...

If the file that was downloaded is intact is returns nothing

If the file is damaged or not correct it returned ERROR_XXX

Those are the only things it will return.

Is there a way to call this program to run from my script and then
parse? the output to see if either state is returned?

The good news is the script runs and does everything but the external
file check (woo) so I am making progress.


-P.
--
c y r a t (a_t) f r o n t i e r n e t (d o t) n e t

re: Accessing external file output from script?

In article <40299803$0$41295$a1866201@newsreader.visi.com>,
PWR <cyrat@frontiernet.net> wrote:[color=blue]
>Platform: Windows
>Python: 2.3
>Python Skill: Reading, Learning, but still newbie.
>
>Mission: My mission is writing a script that is triggered from my mail
>server. The script will execute and download a file. The email that
>triggered the message has a file size which is compared to the
>downloaded file to make sure the bytes match. Once that is accomplished
>there is a small program (.exe) that I can run against the file. The
>.exe has two outputs...
>
>If the file that was downloaded is intact is returns nothing
>
>If the file is damaged or not correct it returned ERROR_XXX
>
>Those are the only things it will return.
>
>Is there a way to call this program to run from my script and then
>parse? the output to see if either state is returned?
>
>The good news is the script runs and does everything but the external
>file check (woo) so I am making progress.[/color]

re: Accessing external file output from script?

> I believe you are saying that you want to know a Python idiom[color=blue]
> for launching an external application (MY_SMALL_PROGRAM.exe?),
> perhaps with a command-line argument or two, and collect its
> result back into a Python variable for subsequent processing.
> Is that correct? What does "return" mean to you in this con-
> text? Are you saying that MY_SMALL_PROGRAM.exe puts specific
> output such as "ERROR_XXX" to its stdout (or stderr?), or is
> your focus on the process's exit status?
>
> I suspect you'll end up reading <URL:
> http://python.org/doc/current/lib/module-popen2.html >.
>
> Question for the audience: what are the impediments to making
> <URL: http://python.org/doc/current/lib/module-commands.html >
> available for Windows?[/color]

I don't know if there are many, other than the format of the os.popen
call of commands.getstatusoutput not being understandable to Windows.

On windows, I usually use the following:

def getoutput(cmdline):
fil = os.popen(cmdline, 'r')
output = fil.read()
fil.close()
return output

But I don't bother with the status output.

The reasons may be related to the windows specifics required for
os.popen5 that should be included in some future Python release.

- Josiah