Setting Catalog Item variables via ReST

[Stephen Graham]

I have a requirement to update some variables on a request item via ReST after the item has been logged by an end-user.

I can successfully set the standard fields, but not the variables. When I pass the below body into my PATCH command, the description gets set correctly, but the variable does not:

{
    "description":  "test description",
    "variables":  {
                      "test_field":  "test value"
                  }
}

The 'test_field' is a Single Line Text field in ServiceNow.

[Stephen Graham]

Thanks Chandra,

I think that only works for creating new orders - do you know how to get it to work for updating existing request items?

Thanks!

[Stephen Graham · Accepted solution]

In case anyone else has the same issue, here's the PowerShell script I used to update two variables (Test Field and Test Field2) on an existing RITM:

$instance = "https://<instance>.service-now.com/api/"
$user = ""
$pass = ""
$sys_id = "86d6aa471b233300de6ffc88cc4bcba6" #The sys_id of the RITM

$table = "sc_item_option_mtom" #this table holds the relationship between an RITM and its variables

#Set TLS to 1.2

[Net.ServicePointManager]::SecurityProtocol = [Net.SecurityProtocolType]::Tls12
# Build auth header

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

# Set proper headers

$headers = New-Object "System.Collections.Generic.Dictionary[[String],[String]]"

$headers.Add('Authorization',('Basic {0}' -f $base64AuthInfo))

$headers.Add('Accept','application/json')

$headers.Add('Content-Type','application/json')

# Specify endpoint uri

$uri = "$instance/now/table/$table"+"?sysparm_query=request_item=$sys_id" #queries for the sys_id of the RITM in the sc_item_option_mtom table

# Specify HTTP method

$method = "GET" #We are just doing a GET because at this point we just want to retrieve the link records, which we can use later to populate the variables in the sc_item_option table  

# Send HTTP request

$response = Invoke-WebRequest -Headers $headers -Method $method -Uri $uri -UseBasicParsing

$response = $response | ConvertFrom-Json #Convert response to a PSObject

$sc_item_option = $response.result.sc_item_option.value #This is the value of the sc_item_option field in the sc_item_option_mtom table. This is a reference field so it will be a sys id. If there are multiple variables, then a list would be returned

foreach ($id in $sc_item_option) #loop through each variable
{
    
    $table2 = 'sc_item_option'
    $uri2 = "$instance/now/table/$table2/$id"+"?sysparm_display_value=all"
    $method2 = 'PATCH'
    
    #perform a GET to find out what the variable's display value is (i.e. which question it relates to)
    $response2 = Invoke-WebRequest -Headers $headers -Method $method -Uri $uri2 -UseBasicParsing

    $response2 = $response2 | ConvertFrom-Json

    $variableName = $response2.result.item_option_new.display_value #This is the display name of the question in ServiceNow
    $variableValue = $response2.result.value.value #This is current value (answer) of the question in ServiceNow

    $method2 = 'PATCH' #PATCH to update the field

    #Instantiate empty body object to populate later
    $body = @{

    }
    
    #Populate the fields with different values depending on the question. The $variableName must exactly match the text of the question on the catalog item in ServiceNow
    If ($variableName -eq 'Test Field')
    {
        $body.add('value', 'testing field 1')
    }
    elseif ($variableName -eq 'Test Field2') 
    {
        $body.clear() #empty the body
        $body.add('value', 'testing field 2')
    }
        
    $bodyJson = $body | ConvertTo-Json

    $response2 = Invoke-WebRequest -Headers $headers -Method $method2 -Uri $uri2 -Body $bodyJson -UseBasicParsing   

}