passthru() + Pipe in subprocess = Traceback (most recent call last): (…) in stdout=subprocess.PIPE) - subprocess

Question

I've got an error when I'm using passthru() to call a python script (using subprocess and pipe) with PHP.
Here is the error:
Traceback (most recent call last):
File "…/Desktop/h.py", line 11, in stdout=subprocess.PIPE)
#set up the convert command and direct the output to a pipe
File "/System/Library/Frameworks/Python.framework/Versions/2.5/lib/python2.5/subprocess.py", line 593, in __init__
errread, errwrite)
File "/System/Library/Frameworks/Python.framework/Versions/2.5/lib/python2.5/subprocess.py", line 1079, in _execute_child
raise child_exception
OSError: [Errno 2] No such file or directory
The PHP passthru:
<?php
passthru("/usr/bin/python2.5 /Users/Nagar/Desktop/h.py $argument1 $argument2 1 2>&1");
?>
My Python line which cause the error:
p1 = subprocess.Popen(['convert', fileIn, 'pnm:-'], stdout=subprocess.PIPE) #set up the convert command and direct the output to a pipe
How to use stdout=subprocess.PIPE properly in the subprocess?
Looking forward your answers.

Answer 1

It looks like your PATH doesn't have the directory including the "convert" command. Try replacing:
p1 = subprocess.Popen(['convert', fileIn, 'pnm:-'], stdout=subprocess.PIPE)
with:
p1 = subprocess.Popen(['/full/path/to/convert', fileIn, 'pnm:-'], stdout=subprocess.PIPE)
where "/full/path/to/convert" might be something like "/usr/bin/convert".

Answer 2

It's because it needs to be executed through a shell, so you need to set shell argument to True:
p1 = subprocess.Popen(['convert', fileIn, 'pnm:-'], stdout=subprocess.PIPE, shell=True)convert command and direct the output to a pipe