em_event table additional_Info field is returning [object Object]

[edwio]

We are using Rest API via PowerShell (Invoke-RestMethod),
In order to insert records in the event [em_event] table with a single call, using the web service API.

We successfully inserting events to the em_event table,
But the only problem is with the additional_info field.

For some reason,
The JSON structure of my PowerShell script,
Is causing the output of additional_info, to return as an Object and Not as JSON string.

And as a result,
Not showing the values in additional_info properly, but instead as [object Object]:

This is the JSON structure in my PowerShell script:

# Specify request body
$body = @"
{	"records":	
[
     {
     "source":"MyClass",
     "event_class":"$AtargetResourceType",
     "resource":"$AtargetResourceType",
     "node":"$AtargetResourceName",
     "metric_name":"$Aname",
     "type":"$AsignalType",
     "severity":"$Aseverity",
     "message_key":"$Aid",
	 "u_mc_object":"$AtargetResource",
     "description":"$Adescription",
     "additional_info":"{  
							'u_mc_object_class':'$AsourceCreatedId',
							'u_mc_parameter':'$AmetricName',
							'u_mc_parameter_value':'$AmetricValue'
     					}"
      }     
   ]
}
"@

[Alberto Consonn]

Hi,

use the solution provided to the thread below:

The issue here is that the event engine is expecting additional_info to be a JSON string, but it's being sent as an object instead.

https://community.servicenow.com/community?id=community_question&sys_id=12a24f21dbd8dbc01dcaf3231f96...

If I have answered your question, please mark my response as correct and/or helpful.

Thank you very much

Cheers
Alberto

[edwio]

I already wrote the cause of my problem,

And also reviewed the link you wrote, 
but I'm using PowerShell Not Perl.

[SteveMac1]

The problem is the single quotes. Single quotes are not valid in JSON. Replace them with double quotes and you'll be good to go. I believe you can embed double quotes in a string by escaping them with a backtick character (`). 

[edwio]

@SteveMac, at first i thought that this could be the reason. but event with double quotes i"m still getting the same resault: [object Object].

This is the full ServiceNow Section in my Script:

# Eg. User name="admin", Password="admin" for this code sample.
$user = "MyUser"
$pass = "MyPassword"

# Build auth header
$base64AuthInfo = [Convert]::ToBase64String([Text.Encoding]::ASCII.GetBytes(("{0}:{1}" -f $user, $pass)))

# Set proper headers for SNOW
$SNOWheaders = New-Object "System.Collections.Generic.Dictionary[[String],[String]]"
$SNOWheaders.Add('Authorization',('Basic {0}' -f $base64AuthInfo))
$SNOWheaders.Add('Accept','application/json')
$SNOWheaders.Add('Content-Type','application/json')

# Specify endpoint uri

# SNOW URI
$uri = "https://servicenow-myinstance/api/global/em/jsonv2"

# Specify HTTP method
$method = "Post"

# Specify request body
$body = @"
{	"records":	
[
     {
     "source":"MyClass",
     "event_class":"$AtargetResourceType",
     "resource":"$AtargetResourceType",
     "node":"$AtargetResourceName",
     "metric_name":"$Aname",
     "type":"$AsignalType",
     "severity":"$Aseverity",
     "message_key":"$Aid",
	 "u_mc_object":"$AtargetResource",
     "description":"$Adescription",
     "additional_info":"{  
							"u_mc_object_class":"$AsourceCreatedId",
							"u_mc_parameter":"$AmetricName",
							"u_mc_parameter_value":"$AmetricValue"
     					}"
      }     
   ]
}
"@

$bodyJson = $body | ConvertTo-Json

# Send HTTP reques
$response = Invoke-RestMethod -Headers $SNOWheaders -Method $method -Uri $uri -Body $bodyJson -ContentType "application/json" -UseBasicParsing