M365IdentityPosture

1.0.0

Private/DataCollection/Get-GraphTenantMetadata.ps1

function Get-GraphTenantMetadata {
    <#
    .SYNOPSIS
        Retrieves basic tenant metadata (tenant id and default onmicrosoft domain).
 
    .DESCRIPTION
        Calls /organization selecting id, tenantId, verifiedDomains. Determines the managed *.onmicrosoft.com domain
        and computes a short name (prefix) for use in SPO admin URL construction.
 
    .OUTPUTS
        PSCustomObject: TenantId, OnmicrosoftDomain, TenantShortName (or $null on failure).
 
    .EXAMPLE
        $tenantMetadata = Get-GraphTenantMetadata
    #>
    [CmdletBinding()] param()
    try {
        $organizationGraphRequest = @{
            Method      = 'GET'
            Uri         = 'https://graph.microsoft.com/v1.0/organization?$select=id,tenantId,verifiedDomains'
            ErrorAction = 'Stop'
        }
        $organizationResponse = Invoke-MgGraphRequest @organizationGraphRequest
    
        if (-not $organizationResponse.value) { return $null }
    
        $organizationData = $organizationResponse.value[0]
        $tenantId = $organizationData.tenantId
        $onMicrosoftDomain = ($organizationData.verifiedDomains | 
                Where-Object { $_.name -like '*.onmicrosoft.com' -and $_.type -eq 'Managed' } |
                Sort-Object { -not $_.isDefault }, { -not $_.isInitial } | 
                Select-Object -First 1).name
        $tenantShortName = $null
        if ($onMicrosoftDomain -and $onMicrosoftDomain -match '^([a-z0-9-]+)\.onmicrosoft\.com$') { 
            $tenantShortName = $Matches[1] 
        }
    
        return [pscustomobject]@{ 
            TenantId          = $tenantId
            OnmicrosoftDomain = $onMicrosoftDomain
            TenantShortName   = $tenantShortName 
        }
    }
    catch { 
        return $null 
    }
}