Re: [Jython-users] Jython Caching Argv

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Hi Jeff, Adam,

Thanks a ton for the prompt reply. Few clarifications:

   1. The *python.home* path I gave is the *local* Python 2.7 installation
   path. I assume you are saying this should be *CPython* home rather. I
   will try this after installing CPython locally.
   2. The problem is that I wish to deploy my code on Pivotal Cloud Foundry
   (PCF) where I would not be able to install anything else apart from the
   application JAR, no file-system access is available as since the code runs
   inside PCF containers, I cannot expect Python or CPython to be installed on
   that system.
   3. I tried several thing to make it work (for e.g. extracted the *Lib*
   folder from the JAR and added it on the classpath, also renamed the JAR to
   *jython.jar* and added it to classpath, supplied the Lib folder path as
   *python.path* as well), none of these worked. It seems if there is no
   way to supply the absolute path, then there is no way to make it work from
   within a Java JAR.
   4. My Python script is current 400 LOCs and will keep on growing, so I
   cannot possibly call its *functions* from my Java code as it would
   couple it to the Python code. I guess the only better option would be to
   port this Python code to Java.
   5. I am using Jython Standalone JAR 2.7.1 from Maven central. I think
   what you are saying is that instead of passing command line arguments
   (argv) to the static *initialize* method I can pass it to the
   *PythonInterpreter* object rather. I am not sure how, as I do not such
   any such method in the API. Is there a code example available?

Thanks again for your help.

Deb

On Sun, 12 Aug 2018 at 03:26, Adam Burke <ada...@gm...> wrote:

> Hi Deb
>
> On top of that, depending on how the script you’re calling is written, it
> might be useful to call one layer down instead of using I/O. Jython lets
> you work with python objects fairly directly from Java, and call Python
> functions directly as well. So if your python script has internal functions
> and classes, you could call straight into them.
>
> YMMV.
>
> Adam
>
> > 在 2018年8月12日，上午7:41，Jeff Allen <ja...@fa...> 写道：
> >
> > I don't know anything about Spring Boot, but the standalone JAR must be
> on your path for you to be able to refer to "PythonInterpreter" in your
> code. So by "not detected" I guess you mean that Jython appear not to find
> its library (which is in the standalone JAR). Jython guesses based on the
> path to the JAR it seems to be running from (that org.python.core.Py was
> loaded from) but telling it is safer.
> >
> > This bit struck me as odd:
> >
> > props.put("python.home", "C:\\Dev\\Python27");
> >
> > That's not the location of CPython is it? That would cause you a world
> of confusion.
> >
> > However, none of that addresses your question about argv (meaning
> sys.argv I suppose). The important observation here is that
> "PythonInterpreter.initialize" is a static method that sets a default argv
> that all interpreters will see as they are created. It makes a big
> difference now what version you are using. In 2.7.0, all interpreters were
> really the same interpreter: you got a separate namespace for your main,
> but the modules where all the same, in particular every interpreter shared
> sys. In 2.7.1, each interpreter gets its own sys, and so each module used
> is loaded again for each interpreter.
> >
> > I cannot say off the top of my head what the behaviour of the default
> argv and sys.argv is, but I'm pretty sure the interpreter you make in the
> next line has its own sys and the sys.argv you could set independently,
> although not in the constructor.
> >
> > Jeff Allen
> >
> >> On 11/08/2018 20:16, Debashish wrote:
> >> Hi,
> >>
> >> I am trying to call a Python Script from a Spring Boot applications.
> There are two issues I am facing:
> >> (1) The Jython Standalone JAR is not detected and I am forced to supply
> the local install path as "python.home" to make it work.
> >> (2) Once I initialize the /PythonInterpreter/ class, it seems it caches
> the argv I supply to it as for the subsequent invocation it uses the same
> argv values. I do call the close() method to do cleanup, but it doesn't
> help :(
> >>
> >>                 Properties preprops = System.getProperties();
> >> Properties props = new Properties();
> >>
> >> props.put("python.home", "C:\\Dev\\Python27");
> >> props.put("python.console.encoding", "UTF-8");
> >> props.put("python.security.respectJavaAccessibility", "false");
> >> props.put("python.import.site", "false");
> >>
> >> PythonInterpreter.initialize(preprops, props, arguments);
> >> PythonInterpreter pyInterpreter = new PythonInterpreter();
> >>
> >> try {
> >> resource = new ClassPathResource("mypyscript.py");
> >> out = new ByteArrayOutputStream();
> >> err = new ByteArrayOutputStream();
> >> pyInterpreter.setOut(out);
> >> pyInterpreter.setErr(err);
> >> pyInterpreter.execfile(resource.getInputStream());
> >> result[0] = out.toString(); // reading the output
> >> result[1] = err.toString(); // reading any error
> >> } catch (Exception e) {
> >> throw new Exception(e);
> >> } finally {
> >> try {
> >> if (out != null)
> >> out.close();
> >> if (err != null)
> >> err.close();
> >> pyInterpreter.close();
> >> } catch (IOException e) {
> >> e.printStackTrace();
> >> }
> >> }
> >>
> >> Please help.
> >>
> >> Thanks,
> >>
> >> Deb
> >>
> >>
> >>
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> >
> >
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