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Re: Calling Java jar class with parameter from Python

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  Re: Calling Java jar class with parameter from Python Peter Otten <__peter__@web.de> - 2012-07-21 14:20 +0200
    Re: Calling Java jar class with parameter from Python Roy Smith <roy@panix.com> - 2012-07-21 09:57 -0400
      Re: Calling Java jar class with parameter from Python jasonveldicott@gmail.com - 2012-07-21 09:11 -0700
    Re: Calling Java jar class with parameter from Python jasonveldicott@gmail.com - 2012-07-21 09:03 -0700
    Re: Calling Java jar class with parameter from Python jasonveldicott@gmail.com - 2012-07-21 09:03 -0700

#25742 — Re: Calling Java jar class with parameter from Python

Jason Veldicott wrote:

> subprocess.Popen(["C:\\Program Files
> (x86)\\Java\\jdk1.7.0_05\\bin\\java.exe", "-cp
> c:\\antlr\\antlr-3.4-complete.jar org.antlr.Tool",
> "C:\\Users\\Jason\\Documents\\antlr\\java grammar\\Java.g"],
> stdout=subprocess.PIPE, shell=True ).communicate()
> 
> 
> Obviously, some trick is being missed.  Could anyone shed light on what it
> may be?

File names with spaces can be tricky. Try thoroughly separating the 
individual arguments and let subprocess do the necessary escaping. 
I think it should be

subprocess.Popen([
  "C:\\Program Files (x86)\\Java\\jdk1.7.0_05\\bin\\java.exe",
  "-cp",
  "C:\\antlr\\antlr-3.4-complete.jar",
  "org.antlr.Tool",
  "C:\\Users\\Jason\\Documents\\antlr\\java grammar\\Java.g"],
   stdout=subprocess.PIPE).communicate()

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#25743

In article <mailman.2380.1342873263.4697.python-list@python.org>,
 Peter Otten <__peter__@web.de> wrote:

> subprocess.Popen([
>   "C:\\Program Files (x86)\\Java\\jdk1.7.0_05\\bin\\java.exe",
>   "-cp",
>   "C:\\antlr\\antlr-3.4-complete.jar",
>   "org.antlr.Tool",
>   "C:\\Users\\Jason\\Documents\\antlr\\java grammar\\Java.g"],
>    stdout=subprocess.PIPE).communicate()

You might also want to try raw strings.  This should be identical to 
Peter's version, but easier to read:

subprocess.Popen([
  r"C:\Program Files (x86)\Java\jdk1.7.0_05\bin\java.exe",
  r"-cp",
  r"C:\antlr\antlr-3.4-complete.jar",
  r"org.antlr.Tool",
  r"C:\Users\Jason\Documents\antlr\java grammar\Java.g"],
   stdout=subprocess.PIPE).communicate()

although I would probably refactor it like:

args = [r"C:\Program Files (x86)\Java\jdk1.7.0_05\bin\java.exe",
        r"-cp",
        r"C:\antlr\antlr-3.4-complete.jar",
        r"org.antlr.Tool",
        r"C:\Users\Jason\Documents\antlr\java grammar\Java.g",
       ]
proc = subprocess.Popen(args, stdout=subprocess.PIPE)
proc.communicate()

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#25751

On Saturday, July 21, 2012 6:57:48 AM UTC-7, Roy Smith wrote:
> In article <mailman.2380.1342873263.4697.python-list@python.org>,
>  Peter Otten <__peter__@web.de> wrote:
> 
> > subprocess.Popen([
> >   "C:\\Program Files (x86)\\Java\\jdk1.7.0_05\\bin\\java.exe",
> >   "-cp",
> >   "C:\\antlr\\antlr-3.4-complete.jar",
> >   "org.antlr.Tool",
> >   "C:\\Users\\Jason\\Documents\\antlr\\java grammar\\Java.g"],
> >    stdout=subprocess.PIPE).communicate()
> 
> You might also want to try raw strings.  This should be identical to 
> Peter's version, but easier to read:
> 
> subprocess.Popen([
>   r"C:\Program Files (x86)\Java\jdk1.7.0_05\bin\java.exe",
>   r"-cp",
>   r"C:\antlr\antlr-3.4-complete.jar",
>   r"org.antlr.Tool",
>   r"C:\Users\Jason\Documents\antlr\java grammar\Java.g"],
>    stdout=subprocess.PIPE).communicate()
> 
> although I would probably refactor it like:
> 
> args = [r"C:\Program Files (x86)\Java\jdk1.7.0_05\bin\java.exe",
>         r"-cp",
>         r"C:\antlr\antlr-3.4-complete.jar",
>         r"org.antlr.Tool",
>         r"C:\Users\Jason\Documents\antlr\java grammar\Java.g",
>        ]
> proc = subprocess.Popen(args, stdout=subprocess.PIPE)
> proc.communicate()

The r string notation at least saves having to double type a bunch of backslashes, although the appearance prepended to the string takes a little getting used to.

Visually the separate array to handle arguments is perhaps cleaner, having more resemblance to the original command.

Thanks for the tips.

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#25746

On Saturday, July 21, 2012 5:20:48 AM UTC-7, Peter Otten wrote:
> Jason Veldicott wrote:
> 
> > subprocess.Popen(["C:\\Program Files
> > (x86)\\Java\\jdk1.7.0_05\\bin\\java.exe", "-cp
> > c:\\antlr\\antlr-3.4-complete.jar org.antlr.Tool",
> > "C:\\Users\\Jason\\Documents\\antlr\\java grammar\\Java.g"],
> > stdout=subprocess.PIPE, shell=True ).communicate()
> > 
> > 
> > Obviously, some trick is being missed.  Could anyone shed light on what it
> > may be?
> 
> File names with spaces can be tricky. Try thoroughly separating the 
> individual arguments and let subprocess do the necessary escaping. 
> I think it should be
> 
> subprocess.Popen([
>   "C:\\Program Files (x86)\\Java\\jdk1.7.0_05\\bin\\java.exe",
>   "-cp",
>   "C:\\antlr\\antlr-3.4-complete.jar",
>   "org.antlr.Tool",
>   "C:\\Users\\Jason\\Documents\\antlr\\java grammar\\Java.g"],
>    stdout=subprocess.PIPE).communicate()

That did the trick, thanks.  

I had the impression from another post that the breaking up of command strings into subprocess arguments could be done arbitrarily as needed to deal with nested inverted commas.  Obviously as you've shown, this is not the case, at least for Popen.

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#25747

On Saturday, July 21, 2012 5:20:48 AM UTC-7, Peter Otten wrote:
> Jason Veldicott wrote:
> 
> > subprocess.Popen(["C:\\Program Files
> > (x86)\\Java\\jdk1.7.0_05\\bin\\java.exe", "-cp
> > c:\\antlr\\antlr-3.4-complete.jar org.antlr.Tool",
> > "C:\\Users\\Jason\\Documents\\antlr\\java grammar\\Java.g"],
> > stdout=subprocess.PIPE, shell=True ).communicate()
> > 
> > 
> > Obviously, some trick is being missed.  Could anyone shed light on what it
> > may be?
> 
> File names with spaces can be tricky. Try thoroughly separating the 
> individual arguments and let subprocess do the necessary escaping. 
> I think it should be
> 
> subprocess.Popen([
>   "C:\\Program Files (x86)\\Java\\jdk1.7.0_05\\bin\\java.exe",
>   "-cp",
>   "C:\\antlr\\antlr-3.4-complete.jar",
>   "org.antlr.Tool",
>   "C:\\Users\\Jason\\Documents\\antlr\\java grammar\\Java.g"],
>    stdout=subprocess.PIPE).communicate()

That did the trick, thanks.  

I had the impression from another post that the breaking up of command strings into subprocess arguments could be done arbitrarily as needed to deal with nested inverted commas.  Obviously as you've shown, this is not the case, at least for Popen.

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