How to pass JSON to PowerShell MID server script

[chadlockwood]

I am trying to pass JSON from my workflow to a PowerShell MID server script through a Run Powershell activity. The JSON string is being created in a Run Script activity:

var dataObj = {};
dataObj.displayName = workflow.scratchpad.displayName;
dataObj.employeeNumber = workflow.scratchpad.employeeNumber;
dataObj.manager = workflow.scratchpad.manager;
dataObj.title = workflow.scratchpad.title;
workflow.scratchpad.employeeJSON = new global.JSON().encode(dataObj);

I then enter the following in the Powershell script variables field on the activity:

{
       "scratchpadData":'${workflow.scratchpad.employeeJSON}'
}

The PowerShell script is this (for testing purposes only):

$psVariable = $env:SNC_scratchpadData | ConvertFrom-JSON
Write-Host $psVariable

The output I would expect to see:

{"displayName":"Carl Plowman","employeeNumber":"12345","manager":"Duffy McBean","title":"Overlord II"}

Instead I get an error from the activity:

*** Invalid JSON primitive: object.Stack Trace:       at
System.Web.Script.Serialization.JavaScriptObjectDeserializer.DeserializePrimitiveObject()at
System.Web.Script.Serialization.JavaScriptObjectDeserializer.DeserializeInternal(Int32 depth)at System.Web.Script.Serialization.JavaScriptObjectDeserializer.DeserializeList(Int32 depth)at
System.Web.Script.Serialization.JavaScriptObjectDeserializer.DeserializeInternal(Int32 depth)at System.Web.Script.Serialization.JavaScriptObjectDeserializer.BasicDeserialize(String input, Int32 depthLimit,
JavaScriptSerializer serializer)at System.Web.Script.Serialization.JavaScriptSerializer.Deserialize(JavaScriptSerializer
serializer, String input, Type type, Int32 depthLimit)at
Microsoft.PowerShell.Commands.ConvertFromJsonCommand.ProcessRecord()at
System.Management.Automation.CommandProcessor.ProcessRecord()

I suspect this has to do with the fact that when I enter the JSON into the PowerShell script variables field, it effectively becomes JSON inside of JSON. When I change the PowerShell script to simply print out the data that has been passed:

Write-Host $env:SNC_scratchpadData

I see this in the activity output:

[object Object]

If I eliminate the MID server script file and write similar PowerShell code directly into the Command field in the activity, and pass the workflow scratchpad variable directly to the script:

Write-Host '${workflow.scratchpad.employeeJSON}'

I get the expected output:

{"department":"123","displayName":"Carl Plowman","employeeNumber":"12345","manager":"Duffy McBean","title":"Overlord II"}

I am looking for assistance in either encapsulating the JSON string from the workflow in a manner that it is useable by the MID server script file -OR- handling what I am currently sending to the MID server script file in a way that makes it useful.

Thank you for your time,

Chad Lockwood

[chadlockwood · Accepted solution]

Ok. We got this sorted out.

The PowerShell script variables field on the Run Powershell activity is expecting "Additional parameters, in JSON format". In all previous workflows I've created, I did the following:

{
   "key name":"${workflow.scratchpad.key value}"
}

The scratchpad variable had always been a string so this worked.

My workflow.scratchpad.employeeJSON variable was configured as a JSON string before I put it in the PowerShell script variables field, so it did not require the open and close braces -OR- the additional key name. My scratchpad variable value was:

{"department":"123","displayName":"Carl Plowman","employeeNumber":"12345","manager":"Duffy McBean","title":"Overlord II"}

If I entered just ${workflow.scratchpad.employeeJSON} into the PowerShell script variables field, in my PowerShell code I can do this:

Write-Host $env:SNC_displayName

and the output is Carl Plowman

I'm please with this result as it allows me to pass a full JSON string, created from JavaScript, into PowerShell.

I hope this helps if anyone else is running into this issue.

Chad