Handle null values in directory lookups

Added null-coalescing operators to ensure $Users and $ServicePrincipals are always arrays, preventing potential errors when responses or cached data are missing or null. Also added -ErrorAction SilentlyContinue to ConvertFrom-Json calls for more robust error handling.

Author: JohnDuprey

Modules/CIPPCore/Public/Webhooks/Test-CIPPAuditLogRules.ps1

@@ -176,10 +176,10 @@ function Test-CIPPAuditLogRules {
                 }
             )
             $Response = New-GraphBulkRequest -TenantId $TenantFilter -Requests $Requests
-            $Users = ($Response | Where-Object { $_.id -eq 'users' }).body.value
+            $Users = ($Response | Where-Object { $_.id -eq 'users' }).body.value ?? @()
             $Groups = ($Response | Where-Object { $_.id -eq 'groups' }).body.value ?? @()
             $Devices = ($Response | Where-Object { $_.id -eq 'devices' }).body.value ?? @()
-            $ServicePrincipals = ($Response | Where-Object { $_.id -eq 'servicePrincipals' }).body.value
+            $ServicePrincipals = ($Response | Where-Object { $_.id -eq 'servicePrincipals' }).body.value ?? @()
             # Cache the lookups for 1 day
             $Entities = @(
                 @{
@@ -208,10 +208,10 @@ function Test-CIPPAuditLogRules {
             Write-Information "Cached directory lookups for tenant $TenantFilter"
         } else {
             # Use cached lookups
-            $Users = ($Lookups | Where-Object { $_.RowKey -eq 'users' }).Data | ConvertFrom-Json
+            $Users = (($Lookups | Where-Object { $_.RowKey -eq 'users' }).Data | ConvertFrom-Json -ErrorAction SilentlyContinue) ?? @()
             $Groups = (($Lookups | Where-Object { $_.RowKey -eq 'groups' }).Data | ConvertFrom-Json -ErrorAction SilentlyContinue) ?? @()
             $Devices = (($Lookups | Where-Object { $_.RowKey -eq 'devices' }).Data | ConvertFrom-Json -ErrorAction SilentlyContinue) ?? @()
-            $ServicePrincipals = ($Lookups | Where-Object { $_.RowKey -eq 'servicePrincipals' }).Data | ConvertFrom-Json
+            $ServicePrincipals = (($Lookups | Where-Object { $_.RowKey -eq 'servicePrincipals' }).Data | ConvertFrom-Json -ErrorAction SilentlyContinue) ?? @()
             Write-Information "Using cached directory lookups for tenant $TenantFilter"
         }