Python Demo

Technical Information

This solution demonstrates the four scenarios on how you can use Python in your solution:

• Python Shell
• Python Standard
• Python and .NET Intermixed
• Python DataAccess API

Requirements

The Python Shell integration requires Python releases 3.7 onwards and the installation of Python.NET..

Setup Steps:

    1.    Install Python and Python.NET in the machines where you run the application and on those using the Solution Designer.
    2.    Configure the Solution Settings to select the appropriate Python shell folder.

Each solution can specify its own Python interpreter, facilitating the development and maintenance of different solutions that may require different Python versions.

 Click here to expand on how to Install Python

You can download Python here.

Check the Use Admin Privileges, and the option to Customize the installation.

During the installation of the Python Engine,select the option to “Install for all users”.

if You install python under your local user, you may have issues when running the solution as a service, or deployment the solution for production.

This image can be slightly different to your Python version, but always enable the options equivalent to:

• Add Python.exe to PATH

Specially in the production server.

• Install with admin rights to all users,
• Customize the installation to installation in the Program Files, instead of Users folder

Once you've downloaded, open command prompt as an ADMINISTRATOR and type “pip install pythonnet”. For this work, you'll need internet access. If internet is not available, download and install manually.

Once Python .NET has been installed, you can then start using Python in your solution.

Python Shell Integration

This integration calls external Python files, passing optional arguments to it, and uses he Python Shell to execute the code capturing the output back to the solution.  

# This code call the execution of the external file using Python Shell 
# with the optional args defined in this initial section
#
# The macro _ExecutionPath_ is replaced by the path where the solution is set to execute
# Replace that macro by a specific path, or user other built-in macros as nedded
#

arg1 = @Tag.Tag1
arg2 = @Tag.Tag2
result = TK.ExecutePythonShell("_ExecutionPath_ExternalSum.py", [arg1, arg2])
@Tag.Result = result

The method TK.ExecutePythonShell() runs the external python interpreter capturing the ouput, and using the result in the code. 

Execution: When this tasks is executed,  the script ExternalSum.py is called, with the values of Tag.Tag1 and Tag.Tag2 passed as arguments. The result, captured from the Print output is captures, and it is stored in Tag.Result(0).

Python Standard Integration

Edit and run the Python code within the platform, with no needing for external files.

When creating a new Task, or a new Class, select Python for the language.

def sub(val1, val2):
    return val1 - val2

result = sub(@Tag.Tag1[1], @Tag.Tag2[1])
@Tag.Result[1] = result

Python and .NET Intermixed

This integration allows C# and VB.Net to call directly methods written and Python, and the Python to consume methods written in .NET languages. 

This is demonstrated in the Python.dbsln demo, when the button is pressed, the following C# expression is executed:

Script.Class.ClassPython.sum(Tag.Tag[1], Tag.Tag[2]

The Script.Class.ClassPython was created in Script > Classes, using the Python language. 

def main(self): return def sum(self, val1, val2): return val1 + val2 def multiply(self, val1: int, val2: int): return val1 * val2

Python DataAccess API

This method calls external Python scripts that use the DataAccess API, allowing for interaction with the calling solution, or other solutions in execution.

From the solution, using Scripts Tasks, the following code is executed:

# This code call the execution of the external file using Python Shell with the optional args defined in this initial section
#
# The macro ExecutionPath is replaced by the path where the solution is set to execute
# Replace that macro by a specific path, or user other built-in macros as nedded
#

result = TK.ExecutePythonShell("_ExecutionPath_ExternalSumDataAccess.py", [])

The external Python application will use the DataAccess API to connected with the running solution, to read and write data directly. 

This is the code for the example: ExternalSumDataAccess.py

# TKDataAccess is located with the product installation files
# 
# If you move this code to another computer, replace the 127.0.0.1 to server you want to connect
# This code can only run on computers where the product is installed
#
# The Macros _ToolkitPath_ and _ExecutionPort_ are resolved automatically before we call this Python code
# If you call the py file directly you need to replace those macros
#
# _ToolkitPath_ should be replaced by the product binaries folder (location of T.Toolkit.DLL and other DLLs)
# _ExecutionPort_ should be replaced by the port number TServer is running, ex.: 3101 (which is dependent on the ExecutionProfile)

import sys
installPath = "_ToolkitPath_"
sysPath = ";".join(sys.path)
if sysPath.find(installPath) < 0 :
    sys.path.append(installPath)

from TKDataAccess import TKDataAccess

dataAccess = TKDataAccess()
connectionStatus = dataAccess.Connect("127.0.0.1:_ExecutionPort_", "guest", "")

if dataAccess.IsConnected() :

	value1 = dataAccess.GetObjectValue("Tag.Tag1[3]")
	value2 = dataAccess.GetObjectValue("Tag.Tag2[3]")
	ret = value1 / value2
	dataAccess.SetObjectValue("Tag.Result[3]", ret)
	print(str(ret))
	dataAccess.Disconnect()

Reference

→ See Python Integration for general information.

→ See Scripts Module, for modules information on tasks and classes.

In this section: