PythonScriptActivity

Category: Common Steps Namespace: CMS.Plugin.FlowManagement.Domain.FlowBusiness.Activitys Base Class: ActionActivity Module: FlowManagement.Domain

Overview

PythonScriptActivity is a node used to execute Python scripts directly within a flow. Inheriting from ActionActivity, it uses the IronPython engine to execute inline Python script code at runtime. This node supports parameter mapping and result extraction, allowing flexible data calculation, transformation, and processing.

Unlike ScriptCallActivity, PythonScriptActivity allows writing Python code directly in the node configuration without pre-configuration in script management, suitable for simple data processing and calculation scenarios.

Business Scenarios

Applicable Scenarios

• Data Calculation: Execute mathematical calculations, statistical analysis, etc.
• Data Transformation: String processing, format conversion, encoding/decoding
• Condition Judgment: Complex business rule judgment
• Data Validation: Data format validation, range checking
• Rapid Prototyping: Quickly implement and test business logic

Role in the System

PythonScriptActivity acts as an inline script executor in the LMES flow system:

• Directly executes configured Python scripts
• Supports passing parameters from flow context
• Supports writing execution results back to flow context
• Uses IronPython engine, compatible with Python 2.x syntax

Configuration Instructions

Basic Configuration

Property Name	Type	Required	Default Value	Description
Script	string	Yes	-	Execution script, Python script for calculation
Mapping	ParameterMapCollection	No	Empty Collection	Parameter matching, pass flow parameters as call arguments
ResultParameter	ResultParameterCollection	No	Empty Collection	Result parameters, names to store results in flow context
Action	ActionType	No	Execute	Execution timing (Inherited from ActionActivity)
IsSynchronous	bool	No	true	Whether to execute synchronously (Inherited from ActionActivity)

Configuration Details

Script

Description: Python script code to run during flow execution. Script executes using IronPython engine, compatible with Python 2.x syntax.

Value Range: String, valid Python code

Notes:

• Uses IronPython engine, some Python 3.x features may not be supported
• Script automatically adds current working directory to sys.path
• Can use import to import standard libraries and custom modules

Mapping

Description: Parameter mapping configuration, defining how to pass parameters from flow context to Python script.

Parameter Mapping Model:

• Source: Parameter name in flow context (Data Source)
• Target: Variable name in Python script (Target Variable)

Notes:

• Mapped parameters will be available as Python variables in the script
• Parameter types are automatically converted to corresponding Python types

ResultParameter

Description: Result parameter configuration, defining how to write Python script execution results back to flow context.

Result Parameter Model:

• Name: Variable name in Python script, also the key name written to flow context

Notes:

• After script execution, value is retrieved from Python scope for the specified variable
• Results are written to flow context in order

Flow Context

Input Parameters

Parameter Name	Type	Description
Mapping.Source	any	Parameters passed to script via Mapping configuration

Output Parameters

Parameter Name	Type	Description
ResultParameter.Name	any	Results retrieved from script via ResultParameter configuration

Usage Examples

Basic Example: Simple Calculation

{
  "Type": "PythonScriptActivity",
  "Name": "Calculate Total",
  "Alias": "CalcTotal",
  "Script": "total = price * quantity",
  "Mapping": [
    { "Source": "Price_Value", "Target": "price" },
    { "Source": "Quantity_Value", "Target": "quantity" }
  ],
  "ResultParameter": [
    { "Name": "total" }
  ]
}

String Processing Example

{
  "Type": "PythonScriptActivity",
  "Name": "Format Barcode",
  "Alias": "FormatBarcode",
  "Script": "formatted = prefix + barcode.zfill(10) + suffix",
  "Mapping": [
    { "Source": "Barcode_Value", "Target": "barcode" },
    { "Source": "Prefix_Value", "Target": "prefix" },
    { "Source": "Suffix_Value", "Target": "suffix" }
  ],
  "ResultParameter": [
    { "Name": "formatted" }
  ]
}

Notes

• ⚠️ IronPython Limitations: Uses IronPython engine, some Python 3.x features not supported
• ⚠️ Performance: New Python engine created for each execution, frequent calls may affect performance
• ⚠️ Type Conversion: Parameters automatically convert types between .NET and Python
• ⚠️ Exception Handling: Script execution exceptions interrupt flow, add exception handling in script
• ⚠️ Security: Scripts can access system resources, note security risks

Related Nodes

• ActionActivity: Base class for Python script node
• ScriptCallActivity: Node to call pre-configured scripts
• MethodCallActivity: Node to call C# methods
• ApiCallActivity: Node to call APIs

Update History

Date	Version	Description
2025-11-28	1.0	Initial version

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Last updated: 2025-11-28