Python Integration

Installation and Setup

The .NET integration is currently compatible and tested with Python releases 3.7 - 3.11. While earlier and newer versions may work with most features, they are not officially tested or supported.

Setup Steps:

    1.    Install Python on 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 Python interpreter, facilitating the development and maintenance of different solutions that may require different Python versions.

Using Python in the Solution

The Python code cabe used at:

• Script-Tasks: event driven or periodical tasks, running in the server computer. 
• Script Classes: library of methods and  functions that be used in both server and client machines, and by  Python, C# or VB.Net Code.
• Displays CodeBehind: The entry point for the CodeBehind, is a .NET method, but right o first line you can call a Python class sro run the logic
• Graphical Elements and Actions:  When definition the dynamic behavior of the Graphical Elements, the Action and the CodeBehind dynamics do asynchronous calla to server methods, which can be in Python.
• Shell Integration: executing Python code from external files.

# 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

Python Code Editor within the Designer

The code editor is accessed at the Designer Scripts → Code Editor page

Testing your code

When the editor is used Script Tasks, you can test the scripts directly, using the Play button at the Task name line..The console standard output is redirection to the Designer output panel, showing the results of your code.

Accessing Tags and Modules properties

The access to Tags and other properties for other models is exactly the same as C# or VB.Net, just use the '@ symbol to access directly the properties, as shown in the image.''@tag.Tag1

.NET Interoperability

Calling ScriptClass Methods

At the Script namespace, any code in your solution, call call methods defined on the script classes. 

@Script.Class.TestClass.ExempleMethod(param1, param2)

This activation is independent from the language the class was creating. Meaning C# and VB.NET can call Python classes, and Python code call .NET classes.

Extensibility Toolkit

We provide a toolkit in Python (TKDataAccess.py) which allows the Python code and application to interact with the Studio projects.

TKDataAccess.py

You can create code in the Python environment and use the TKDataAccess.py file to interact with the projects. 

Below are some methods from TKDataAccess.py that you can use:

• Open a connection with the server

Connect(runtimeHostAddress, userName, password):

runtimeHostAddress  =  IP address or server name
userName  = User name.
password = Password

• Get a server connection status

GetConnectionStatus ()                 

• Check your script's connection to the server

IsConnected ()

• Disconnect from Server

Disconnect()

• Set a flag waiting value from server

SetSyncFlag(flag):

flag = True wait value from server, false does not wait value from server.

• Retrieve a current value

GetObjectValue(name)

name = TagName

• Set a new value for an object

SetObjectValue(name, newValue)

name = TagName
newValue = new value to set in the tag.

• Execute a method from a remote ScriptClass

ExecuteClassMethodOnServer(className, methodName, parameters)

className = name of the class in the remote project.
methodName = name of the method in the remote class.
parameters = if any, necessary to the invoke the remove method.

Examples

Using Namespace in CodeBehind

In this example, there are two input parameters called val1 and val2 that will be summarized and the result will be stored in the result variable.

The code that executes this action is presented below.

//Defining where locate the .py files that will use
string  pyDefinition  =  @Info.GetExecutionFolder()  +  @"\Calc\algorithm.py"; string pyWorkingFolder = @Info.GetExecutionFolder();

try
{
string error;
Dictionary<string,  object>  param  =  new  Dictionary<string,  object>();

       //Defining the used imports from Python	
string imports = "";
imports += "import sys" + Environment.NewLine;
imports += "from Calc.algorithm import Algorithm" + Environment.NewLine;

      //Creating a .Net object from a Python object	
object algorithm =Python.CreatePythonObjectFromPyFile(pyDefinition, "Algorithm", null);
//Creating a .Net object from a Python object	
object val1 = Python.ToPython(@Tag.val1);
object val2 = Python.ToPython(@Tag.val2);

      //Setting the parameters with the .Net objects that will be used to execute the Python code
param.Clear(); param.Add("algorithm", algorithm); param.Add("val1", val1);
param.Add("val2", val2);

      //Call method to execute Python code
error  =  Python.ExecuteCode("result  =  algorithm.Sum(val1,  val2)",  pyWorkingFolder,  param,  true); 

if (!string.IsNullOrEmpty(error))
throw new Exception(error);

       //Set .Net object with result Python object , return of algorithm.Sum Python method
object result = param["result"];

//Copy .Net object to Tag
Python.CopyPythonObjectToTag(result, @Tag.result.GetName());
}
catch (Exception ex)
{
@Info.Trace("Python: " + (ex.InnerException == null ? ex.Message : ex.InnerException.Message));
}

Using Tasks

In this scenario, we configure a task for the Python language.

In the Standard Output field, we selected a tag called output. This tag type must be text. In the Arguments field, we selected another type of tag called script.

Using the print method, the Python task retrieves the input data and outputs its value inside a string. The sys.argv will receive the Tag.script and the output tag will receive all the values from the print() method.

import sys

value = sys.argv[1] print("Value: " + value) print("That’s  all  folks!")

In this section: