gistfile1.ps1

Import-Module PSTerminalServices

Function OctetToHours ($Octet) 
{ 
    # Function to convert Octet value (byte array) into binary string 
    # representing logonHours attribute. The 168 bits represent 24 hours 
    # per day for 7 days, Sunday through Saturday. The values are converted 
    # into local time. If the bit is "1", the user is allowed to logon 
    # during that hour. If the bit is "0", the user is not allowed to logon. 
    $Bias = (Get-ItemProperty -Path HKLM:\System\CurrentControlSet\Control\TimeZoneInformation).Bias 
    # Account for negative bias. 
    If ($Bias -gt 10080){$Bias = $Bias - 4294967296} 
    $Bias = [Math]::Round($Bias/60, 0, [MidpointRounding]::AwayFromZero) 
 
    # Create an array of 168 bytes, representing the hours in a week. 
    $LH = New-Object 'object[]' 168 
    
    For ($j = 0; $j -le 20; $j = $j + 1) 
    { 
        For ($k = 7; $k -ge 0; $k = $k - 1) 
        { 
            $m = 8*$j + $k - $Bias 
            If ($m -lt 0) {$m = $m + 168} 
            If ($m -gt 167) {$m = $m - 168} 
            If ($Octet[$j] -band [Math]::Pow(2, $k)) {$LH[$m] = "1"} 
            Else {$LH[$m] = "0"} 
        } 
    } 
 
    For ($j = 0; $J -le 20; $j = $J + 1) 
    { 
        $n = 8*$j 
        If ($j -eq 0) {$Hours = [String]::Join("", $LH[$n..($n + 7)])} 
        Else {$Hours = $Hours + [String]::Join("", $LH[$n..($n + 7)])} 
    } 
    Return $Hours 
} 

Function MemberOfUserGroup ( $user ) {
  $user.memberOf.contains('CN=SLL - Remote Desktop Users,OU=Security,OU=SLL - Groups,DC=sll,DC=local')
}

Function LogonHoursHelper ( $user, $date ) {
  $hours = OctetToHours $user.logonHours
  [int]$day_of_week = $date | Get-Date -UFormat %u
  [int]$hour_of_day = $date | Get-Date -UFormat %H
  $position = $day_of_week * 24 + $hour_of_day
  Return ($hours[$position] -eq '0')
}

Function LogonHoursExpiring ( $user ) {
  LogonHoursHelper $user, (Get-Date).AddMinutes(5)
}

Function LogonHoursExpired ( $user ) {
  LogonHoursHelper $user, (Get-Date)
}

Filter BaseFilter {
  if ( ($name = $_.UserName) -and ($name -ne '') -and ($_.State -eq 'Active') ) { 
    $user = Get-ADUser -Identity $name -Properties memberOf, logonHours
    $member_of = MemberOfUserGroup $user
    $hours_expiring = LogonHoursExpiring $user
    if ( $member_of -and $hours_expiring ) { Return $_ }
  }

$Message = "Important`nYour session is ending in five minutes. Please save your work and logoff."

Get-TSSession -ComputerName 'LENDINGLIBRARY1' | BaseFilter | Send-TSMessage -Text $Message