A Question about how to programmatically modify XData Block

Here is an example code to modify or create a production XData block, i guess you can adapt to you needs :

ClassMethod CreateProduction(
	package As%String = "test",
	name As%String = "AutoCreatedProduction",
	xdata As%CharacterStream) As%Status
{
  #Dim produtionClassName As%String = package _ "." _ name
  If ('$ZName(produtionClassName, 4))
  {
  Return$System.Status.Error(5001, "Invalid Production package or name.")
  }
  #Dim productionDefinition As%Dictionary.ClassDefinition// Check if the production already existsIf (##class(%Dictionary.ClassDefinition).%ExistsId(produtionClassName))
  {
	// Open the productionset productionDefinition = ##class(%Dictionary.ClassDefinition).%OpenId(produtionClassName)
  }
  Else
  {
	// Create the production definitionset productionDefinition = ##Class(%Dictionary.ClassDefinition).%New()
  }
  //Set productionDefinition.Name         = produtionClassName
  Set productionDefinition.Super        = "Ens.Production"Set productionDefinition.ClassVersion = 25//// Check if the XData Definition already existsIf (##Class(%Dictionary.XDataDefinition).%ExistsId(produtionClassName_"||ProductionDefinition"))
  {
	// delete the XData Definition$$$ThrowOnError(##Class(%Dictionary.XDataDefinition).%DeleteId(produtionClassName_"||ProductionDefinition"))
  }
  #Dim xdataDefinition As%Dictionary.XDataDefinition = ##Class(%Dictionary.XDataDefinition).%New()
  //Set xdataDefinition.Name = "ProductionDefinition"//Do xdataDefinition.Data.CopyFrom(xdata)
  //// Insert XData Definition into Production DefinitionDo productionDefinition.XDatas.Insert(xdataDefinition)
  //#Dim statusCode As%Status = productionDefinition.%Save()
  //If ($System.Status.IsError(statusCode))
  {
  Return statusCode
  }
  // Compile the production classreturn$System.OBJ.Compile(produtionClassName,"k-d")
}

Not so much magic in it, if you already know how to read it, the content of XData is just a Stream, which can be used both ways. Just Write to it, and %Save it. And you will probably need to compile the class

Class Demo.Test
{

XData OpenAPI [ MimeType = application/json ]
{
}

ClassMethod Update()
{
    set xdata = ##class(%Dictionary.XDataDefinition).IDKEYOpen($ClassName(), "OpenAPI")
    do xdata.Data.Write("{}")
    do xdata.%Save()
}

}

In VSCode, the content of XData will not appear after that, because it happened on the server, and VSCode will not see the changes, you'll need to export it manually