Expression Tag RunScript Invalid Datatype for Dataset (PyDictionary)

Ignition
,
1

I have an expression tag that runs a script (getTrendList()) via runScript().

This is the script:

def getAllTrendPens():
	data = system.db.runNamedQuery("getHistoryTags")
		
	if data is not None:
		historyTagPaths = data.getColumnAsList(0)
		
		trendLabelPaths = [historyTag+".Trend_Label" for historyTag in historyTagPaths]
	
		
		trendLabels_qv = system.tag.readBlocking(trendLabelPaths)
	
		trendLabels = [label.value for label in trendLabels_qv]
		
		colors = ["#66FFFF","#B266FF","#FF3333", "#66FF66", "#000099", "#FF66B2", "#CCCC00", "#000000", "#606060" ]
		
		pens = []
		
		for i, pen in enumerate(trendLabels):
			if pen is not None:
				color = colors[i % len(colors)]
				#print pen
				#print historyTagPaths[i]
				jsonObject = {
						
								  "name": pen,
								  "visible": False,
								  "enabled": True,
								  "selectable": True,
								  "axis": "",
								  "plot": 0,
								  "display": {
								    "type": "line",
								    "interpolation": "curveLinear",
								    "breakLine": True,
								    "radius": 3,
								    "styles": {
								      "normal": {
								        "stroke": {
								          "color": color,
								          "width": 1,
								          "opacity": 0.8,
								          "dashArray": 0
								        },
								        "fill": {
								          "color": color,
								          "opacity": 0.8
								        }
								      },
								      "highlighted": {
								        "stroke": {
								          "color": color,
								          "width": 1,
								          "opacity": 1,
								          "dashArray": 0
								        },
								        "fill": {
								          "color": color,
								          "opacity": 1
								        }
								      },
								      "selected": {
								        "stroke": {
								          "color": color,
								          "width": 1,
								          "opacity": 1,
								          "dashArray": 0
								        },
								        "fill": {
								          "color": color,
								          "opacity": 1
								        }
								      },
								      "muted": {
								        "stroke": {
								          "color": color,
								          "width": 1,
								          "opacity": 0.4,
								          "dashArray": 0
								        },
								        "fill": {
								          "color": color,
								          "opacity": 0.4
								        }
								      }
								    }
								  },
								  "data": {
								    "source": "histprov:MSSQLSERVER1:/drv:ignition-scada-pc:default:/tag:"+historyTagPaths[i],
								    "aggregateMode": "default"
								  }
						
							}
				pens.append(jsonObject)
				
	return pens
	
def getTrendList():

	headers = ["Name", "Pen"]

	pens = trendPens.getAllTrendPens()
	
	names = [pen["name"] for pen in pens]
	
	data = [[name,pen] for name, pen in zip(names, pens)]
		
	dataset = system.dataset.toDataSet(headers, data)
	
	return dataset

When I call trendPens.getTrendList() from the script console it returns a dataset, but when called from the expression I get a type conversion error.

Error_TypeConversion("class org.python.core.PyDictionary: Invalid DataType for Dataset.")
2

You can't nest complex data types in datasets that will be assigned to tags. Because it blows up their serialization for retention. Your jsonObject isn't JSON, it is a python dictionary. Convert it to JSON (string) if you want to store it in a dataset in a tag.

1 Like
3

and what's the best way to do that?

edit: I found

system.util.jsonEncode()
3 Likes
4

How can I get the "name" field out of the JSON object after encoding? Script looks like this now:

def getAllTrendPens():
	data = system.db.runNamedQuery("getHistoryTags")
		
	if data is not None:
		historyTagPaths = data.getColumnAsList(0)
		
		trendLabelPaths = [historyTag+".Trend_Label" for historyTag in historyTagPaths]
	
		
		trendLabels_qv = system.tag.readBlocking(trendLabelPaths)
	
		trendLabels = [label.value for label in trendLabels_qv]
		
		colors = ["#66FFFF","#B266FF","#FF3333", "#66FF66", "#000099", "#FF66B2", "#CCCC00", "#000000", "#606060" ]
		
		pens = []
		
		for i, pen in enumerate(trendLabels):
			if pen is not None:
				color = colors[i % len(colors)]
				#print pen
				#print historyTagPaths[i]
				jsonObject = {
						
								  "name": pen,
								  "visible": False,
								  "enabled": True,
								  "selectable": True,
								  "axis": "",
								  "plot": 0,
								  "display": {
								    "type": "line",
								    "interpolation": "curveLinear",
								    "breakLine": True,
								    "radius": 3,
								    "styles": {
								      "normal": {
								        "stroke": {
								          "color": color,
								          "width": 1,
								          "opacity": 0.8,
								          "dashArray": 0
								        },
								        "fill": {
								          "color": color,
								          "opacity": 0.8
								        }
								      },
								      "highlighted": {
								        "stroke": {
								          "color": color,
								          "width": 1,
								          "opacity": 1,
								          "dashArray": 0
								        },
								        "fill": {
								          "color": color,
								          "opacity": 1
								        }
								      },
								      "selected": {
								        "stroke": {
								          "color": color,
								          "width": 1,
								          "opacity": 1,
								          "dashArray": 0
								        },
								        "fill": {
								          "color": color,
								          "opacity": 1
								        }
								      },
								      "muted": {
								        "stroke": {
								          "color": color,
								          "width": 1,
								          "opacity": 0.4,
								          "dashArray": 0
								        },
								        "fill": {
								          "color": color,
								          "opacity": 0.4
								        }
								      }
								    }
								  },
								  "data": {
								    "source": "histprov:MSSQLSERVER1:/drv:ignition-scada-pc:default:/tag:"+historyTagPaths[i],
								    "aggregateMode": "default"
								  }
						
							}
				pens.append(system.util.jsonEncode(jsonObject))
				
	return pens
	
def getTrendList():

	headers = ["Name", "Pen"]

	pens = trendPens.getAllTrendPens()
	
	names = [pen[0] for pen in pens]
	
	data = [[name,pen] for name, pen in zip(names, pens)]
		
	dataset = system.dataset.toDataSet(headers, data)
	
	return dataset

But my name column is just "{"

Edit: I used system.util.jsonDecode() like so:

def getTrendList():

	headers = ["Name", "Pen"]

	pens = trendPens.getAllTrendPens()
	
	names = [system.util.jsonDecode(pen)["name"] for pen in pens]
	
	data = [[name,pen] for name, pen in zip(names, pens)]
		
	dataset = system.dataset.toDataSet(headers, data)
	
	return dataset
5

A Document tag type instead of a Dataset tag type might be more friendly in your application.

6

How so? I'll be binding the dataset to a dropdown's option prop. I have not used the Document datatype.

7

It should let you avoid the conversion to/from strings. I haven't tried it with a drop-down options prop.