We Keep Coding

Call java .jar package in python using jpype

I'm trying to run a .jar from python, but I get the following error. I need help to solve it.
The python code is:
import jpype
import os.path
jvmPath = jpype.getDefaultJVMPath()
jarPath =os.path.join(os.path.abspath('.'),'C:\Programación\Java\JpypePrueba\dist\JpypePrueba.jar')
dependency = os.path.join(os.path.abspath('.'), "C:\Programación\Java\JpypePrueba")
jpype.startJVM(jvmPath, "-ea", "-Djava.class.path=%s" % jarPath, "-Djava.ext.dirs=%s" % dependency)
JDClass = jpype. JClass("project1.sort")
jd = JDClass()
print (jd.calc(1,2))
jpype.shutdownJVM()
and the java code is:
package project1;
public class sort {
public static void main(String[] args ) {
sort t2 = new sort();
System.out.println ( t2.calc (1, 2)) ;
}
public int calc( int a , int b ) {
return a + b ;
}
}
The error that is generated in python is the following:
runfile('C:/Programación/Java/JpypePrueba/JpypePrueba.py', wdir='C:/Programación/Java/JpypePrueba')
Traceback (most recent call last):
File "C:\Programación\Java\JpypePrueba\JpypePrueba.py", line 17, in <module>
jpype.startJVM(jvmPath, "-ea", "-Djava.class.path=%s" % jarPath, "-Djava.ext.dirs=%s" % dependency)
File "C:\ProgramData\Anaconda3\lib\site-packages\jpype\_core.py", line 166, in startJVM
raise OSError('JVM is already started')
OSError: JVM is already started
The location of my python main code looks like the attached image:
The program should return the sum of 2+1=3.

Pass object to DLL function imported with ctypes

I need to use an existing library in my python application.
This is a library to read a particular data file.
If you are curious you can download it from here https://www.hbm.com/en/2082/somat-download-archive/ (somat libsie).
The first thing I need to do it open the file so my python scripts starts like:
import ctypes
hllDll = ctypes.WinDLL(r"libsie.dll")
context = hllDll.sie_context_new()
file = hllDll.sie_file_open(context, "test.sie".encode())
but I get the following error:
Traceback (most recent call last):
File "C:\Program Files\JetBrains\PyCharm 2019.3.5\plugins\python\helpers\pydev\_pydevd_bundle\pydevd_exec2.py", line 3, in Exec
exec(exp, global_vars, local_vars)
File "<input>", line 1, in <module>
OSError: exception: access violation reading 0x000000009F6C06B8
I verified that the .sie file is accessible.
I think the problem lies in the "context" object that gets passed as first argument. I think the type is the issue.
Here is part of the header file where context is defined:
typedef void sie_Context;
...
SIE_DECLARE(sie_Context *) sie_context_new(void);
/* > Returns a new library context. */
Am I calling these functions correctly?
Is there a problem with passing the context object?
Thanks in advance

On a 64-bit system, return values default to c_int (32-bit). At a minimum, set the .restype to at least a c_void_p to indicate a 64-bit pointer is returned.
Ideally, set .argtypes and .restype for each function called.
import ctypes
hllDll = ctypes.WinDLL(r"libsie.dll")
hllDll.sie_context_new.argtypes = () # optional but recommended
hllDll.sie_context_new.restype = ctypes.c_void_p # add this
hllDll.sie_context_new.argtypes = ctypes.c_void_p, ctypes.c_char_p # guess, need prototype
# hllDll.sie_context_new.restype = ???
context = hllDll.sie_context_new()
file = hllDll.sie_file_open(context, b"test.sie")

SWIG Converting Python list to a char ** example fails

I am following the SWIG tutorial and I'm currently on the section: "32.9.1 Converting Python list to a char **". The example in question returns a malloc error on my machine:
import example
example.print_args(["a","bc","dc"])
python(57911,0x10bd32e00) malloc: *** error for object 0x7f7ee0406b90: pointer being freed was not allocated
python(57911,0x10bd32e00) malloc: *** set a breakpoint in malloc_error_break to debug
1 57911 abort python
1 57911 abort python
The error is unexpected as this is exactly the code that the tutorial offers. Any help welcome! Thanks in advance
Specs:
MacOS Big Sur
Python 3.8
C++17
Here are my setup.py (the whole archive for reproducibility):
#!/usr/bin/env python
"""
setup.py file for SWIG example
"""
from distutils.core import setup, Extension
import os
import sys
import glob
# gather up all the source files
srcFiles = ['example.i']
includeDirs = []
srcDir = os.path.abspath('src')
for root, dirnames, filenames in os.walk(srcDir):
for dirname in dirnames:
absPath = os.path.join(root, dirname)
globStr = "%s/*.c*" % absPath
files = glob.glob(globStr)
includeDirs.append(absPath)
srcFiles += files
extra_args = ['-stdlib=libc++', '-mmacosx-version-min=10.7', '-std=c++17', '-fno-rtti']
os.environ["CC"] = 'clang++'
#
example_module = Extension('_example',
srcFiles, # + ['example.cpp'], # ['example_wrap.cxx', 'example.cpp'],
include_dirs=includeDirs,
swig_opts=['-c++'],
extra_compile_args=extra_args,
)
setup(name='example',
version='0.1',
author="SWIG Docs",
description="""Simple swig example from docs""",
ext_modules=[example_module],
py_modules=["example"],
)

The example code would work with Python 2, but has a bug as well as a syntax change for Python 3. char** must be passed byte strings, which are the default in Python 2 when using "string" syntax, but need a leading b, e.g. b"string" in Python 3.
This works:
import example
example.print_args([b"a",b"bc",b"dc"])
The crash is due to a bug calling free twice if an incorrect parameter type is found. Make the following change to the example:
if (PyString_Check(o)) {
$1[i] = PyString_AsString(PyList_GetItem($input, i));
} else {
//free($1); // REMOVE THIS FREE
PyErr_SetString(PyExc_TypeError, "list must contain strings");
SWIG_fail;
SWIG_fail; ends up called the freearg typemap, which calls free a second time. With this change, you should see the following if passing incorrect arguments, such as a non-list or Unicode strings instead of byte strings:
>>> import argv
>>> argv.print_args(1)
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
File "C:\argv.py", line 66, in print_args
return _argv.print_args(argv)
TypeError: not a list
>>> argv.print_args(['abc','def'])
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
File "C:\argv.py", line 66, in print_args
return _argv.print_args(argv)
TypeError: list must contain strings
>>> argv.print_args([b'abc',b'def'])
argv[0] = abc
argv[1] = def
2
Changing the error message to "list must contain byte strings" would help as well 😊

I want to run dask.dataframe by using jython

I want to run dask in java process by using jython.
I installed dask[complete] by using pip command.
but, java process raise ImportError: dask
so how I can fix this bug?
package test;
import org.python.core.*;
import org.python.util.*;
public class TestJython {
private static PythonInterpreter pi;
public static void main(String[] args) throws PyException {
pi = new PythonInterpreter();
PySystemState sys = pi.getSystemState();
sys.path.append(new PyString("/usr/local/lib/python2.7/dist-packages"));
pi.exec("import dask.dataframe as dd");
}
}
error log :
Exception in thread "MainThread" Traceback (most recent call last):
File "<string>", line 1, in <module>
File "/usr/local/lib/python2.7/dist-packages/dask/dataframe/__init__.py", line 31, in <module>
raise ImportError(str(e) + '\n\n' + msg)
ImportError: Missing required dependencies ['numpy']

Looks like the PythonInterpreter isn't initialized with the correct PYTHONPATH setup. This is not an issue with Dask, but with how you're initializing PythonInterpreter. Looks like you may need to set the python.path system property, or use the JYTHONPATH environment variable: https://www.stefaanlippens.net/jython_and_pythonpath/.
Note that the dask team has no experience running dask in Jython, and cannot guarantee that things will work, or be performant.

How to call python script from c++ (Clion)

OK, so after searching a little too hard over the internet I still have my same issue. I have a very simple python script that opens up the specified excel file and then runs a macro.
I know for a fact that my python script runs as it should stand alone.
I know for a fact that my C++ code runs as it should.
But the combo of both creates a 'com_error'. Just so anyone who sees this knows, these are all the tests I have ran:
(1) simple python script (just prints hello) --> passed
(2) use C++ to run same simple .py script --> passed
(3) more advanecd python script (opens excel, runs macro, save and close) --> pass
(4) usc C++ code to run advanced .py script --> fail.
And there is my problem. this has something to do with the win32com.client and an error the server throws because it cant find the file location (but trust me it can because it passed the 'find file' test)
I'm running Windows7, Python 2.7, And the latest version of JetBrains Clion (2017.1.2).
Any help would be so appreciated. Thanks! Happy coding.
C++ code:
#include <iostream>
#include <Windows.h>
using namespace std;
int main() {
const char *cmd = "python C:\\Users\\Alex.Valente\\Desktop\\python.py";
PROCESS_INFORMATION processInformation = {0};
STARTUPINFO startupInfo = {0};
startupInfo.cb = sizeof(startupInfo);
BOOL result = CreateProcess(NULL, (LPSTR)cmd,
NULL, NULL, FALSE,
NORMAL_PRIORITY_CLASS,
GetEnvironmentStrings(), NULL, &startupInfo, &processInformation);
if(!result){
return -1;
}
WaitForSingleObject( processInformation.hProcess, INFINITE );
return 0;
}
Python Script:
from __future__ import print_function
import unittest
import os.path
import win32com.client
import os
class ExcelMacro(unittest.TestCase):
def test_excel_macro(self):
xlApp = win32com.client.DispatchEx('Excel.Application')
xlsPath = r'C:\Users\Alex.Valente\Desktop\Data.csv'
xlApp.Visible = True
wb = xlApp.Workbooks.Open(Filename=xlsPath)
xlApp.Run("PERSONAL.XLSB!PythonTest")
wb.Save()
wb.Close()
xlApp.Quit()
print("Macro ran successfully!")
if __name__ == "__main__":
unittest.main()
And the Error that is printed after I run it:
======================================================================
ERROR: test_excel_macro (__main__.ExcelMacro)
----------------------------------------------------------------------
Traceback (most recent call last):
File "C:\Users\Alex.Valente\Desktop\python.py", line 25, in test_excel_macro
wb = xlApp.Workbooks.Open(Filename=xlsPath)
File "<COMObject <unknown>>", line 8, in Open
com_error: (-2147417851, 'The server threw an exception.', None, None)
----------------------------------------------------------------------
Ran 1 test in 6.305s
FAILED (errors=1)