PoshBot middleware hook to mark a command as approved is the user is in a certain AD group

adauth.ps1

param(
    $Context,
    $Bot
)

$user = $Context.Message.FromName
$adGroup = 'botusers'

$userGroups = (New-Object System.DirectoryServices.DirectorySearcher("(&(objectCategory=User)(samAccountName=$user)))")).FindOne().GetDirectoryEntry().memberOf
if (-not ($userGroups -contains $adGroup)) {
    $Context.ApprovalState = 'Denied' #[ApprovalState]::Denied
    $Bot.LogInfo("User [$user] is not in AD group [$adGroup]. Command is not approved.")
    return
} else {
    $Context.ApprovalState = 'Approved' #[ApprovalState]::Approved
    $Context
}