Service Payload Scripts

C# scripts help to generate or parse payloads depending on the platform or outside systems. This chapter can be used as development reference.

C# Script Structure

The C# script contains following structure:

• usings
• namespace
  • class declaration
    • overwritten methods from base class
    • your own private methods, properties and fields

Example of DataLogger Payload Script.

//List of usings
using CyberTech;
using HumanOS.Kernel;
using HumanOS.Kernel.DataModel;
using HumanOS.Kernel.PeSeL.DataLogger;
using HumanOS.Kernel.PeSeL.Script;
using HumanOS.Kernel.Utils;
using System;
using System.Collections.Generic;
using System.Text;

//Namespace (can by any)
namespace HumanOS.IoT.Designer.Library.Scripts
{
  /// Your script class
  public class MyDataLoggerScriptObject : TAbstractDataLoggerScriptObject<string>
  {
    ///<see cref="TAbstractDataLoggerScriptObject{T}"/>
    public override void initialize(IKernelAccess Kernel, TPayloadProcessingContext Context)
    {
      //Your code to initial the processing (first time)
    }

    ///<see cref="TAbstractDataLoggerScriptObject{T}"/>
    public override void postProcess(IKernelAccess Kernel, TPayloadProcessingContext Context)
    {
      //Your code to post process data after successful sending
    }

    ///<see cref="TAbstractDataLoggerScriptObject{T}"/>
    public override string[] processPayload(IKernelAccess Kernel, TPayloadProcessingContext Context, List<TDataSet> lstData)
    {
      //Your code to generate the payload
      return new string[] { "MyPayload" };
    }

    //Some private methods and fields 
    private void doInternal() 
    {
      //...
    }
  }
}

Base Class for DataLogger

Each script object must be derived from TAbstractDataLoggerScriptObject<T> for data logging. The T stands for a data type used by the data logger service:

• HumanOS.PeSeL.AzureIoTClient uses byte[].
• HumanOS.PeSeL.MQTTClient uses byte[].
• HumanOS.PeSeL.NodeSpaceDataLogger uses string.
• HumanOS.PeSeL.RestDataLogger uses string.
• HumanOS.PeSeL.RabbitMqClient uses byte[].

The following methods must be overwritten:

Initialize

The initialize method is only called once at the beginning of the processing. Place your initial code here.

The method requires arguments:

Argument	Description	Data Type
Kernel	Access to the HumanOS kernel.	IKernelAccess
Context	Contains information about the service endpoint and data logger.	TPayloadProcessingContext

public override void initialize(IKernelAccess Kernel, TPayloadProcessingContext Context)
{
  //Your code to initial the processing (first time)
}

ProcessPayload

The processPayload method is called each time a payload must be sent to the endpoint. Here, you place the code to generate the payload.

The method requires arguments.

Argument	Description	Data Type
Kernel	Access to the HumanOS kernel.	IKernelAccess
Context	Contains information about the service endpoint and data logger.	TPayloadProcessingContext
lstData	List of data sets to process.	List<TDataSet>

The method returns a list of payloads. Each item in the list is individually sent to the service endpoint.

///<see cref="TAbstractDataLoggerScriptObject{T}"/>
public override string[] processPayload(IKernelAccess Kernel, TPayloadProcessingContext Context, List<TDataSet> lstData)
{
  List<string> lstRetval = new List<string>();

  //Your code to generate the payload

  return lstRetval;
}

PostProcess

The postProcess method is called after a successful sending of the payload.

The method requires arguments. See method Initialize.

///<see cref="TAbstractDataLoggerScriptObject{T}"/>
public override void postProcess(IKernelAccess Kernel, TPayloadProcessingContext Context)
{
  //Your code to post process data after successful sending
}