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I've just published ADExploder. It's a single-script PowerShell app (source) that uses classic Windows Forms and the Directory Services API to be able to browse nodes and properties of Active Directory servers.

I am interested in hearing feedback about my use of PowerShell, whether it can be made more terse or idiomatic, ways that I can improve my usage of either the Windows Forms or Active Directory API, and any other improvements you can think of.

The full body of the script is here:

# Greg Toombs, November 2013

add-type -a (
    'System.DirectoryServices',
    'System.DirectoryServices.AccountManagement',
    'System.Drawing',
    'System.Windows.Forms'
)

function GetConnDlg() {
    $label = new-object Windows.Forms.Label -pr @{
        AutoSize = $true
        Dock = [Windows.Forms.DockStyle]::Top
        Text = 'Hostname'
    }
    $text = new-object Windows.Forms.TextBox -pr @{
        Anchor = [Windows.Forms.AnchorStyles] 'Left, Right, Top'
        MinimumSize = new-object Drawing.Size -a 120, 20
    }
    $ok = new-object Windows.Forms.Button -pr @{
        DialogResult = [Windows.Forms.DialogResult]::OK
        Text = '&Connect'
    }
    $cancel = new-object Windows.Forms.Button -pr @{
        DialogResult = [Windows.Forms.DialogResult]::Cancel
        Text = 'C&ancel'
    }
    $flowh = new-object Windows.Forms.FlowLayoutPanel -pr @{
        AutoSize = $true
        Dock = [Windows.Forms.DockStyle]::Bottom
        FlowDirection = [Windows.Forms.FlowDirection]::RightToLeft
    }
    $flowh.Controls.AddRange(($cancel, $ok))
    $flowv = new-object Windows.Forms.FlowLayoutPanel -pr @{
        AutoSize = $true
        Dock = [Windows.Forms.DockStyle]::Fill
        FlowDirection = [Windows.Forms.FlowDirection]::TopDown
    }
    $flowv.Controls.AddRange(($label, $text))
    $conndlg = new-object Windows.Forms.Form -pr @{
        AcceptButton = $ok
        CancelButton = $cancel
        MaximizeBox = $false
        MinimizeBox = $false
        Padding = new-object Windows.Forms.Padding -a 5
        Size = new-object Drawing.Size -a 230, 130
        StartPosition = [Windows.Forms.FormStartPosition]::CenterParent
        Text = 'Connect'
    }
    $conndlg.Controls.AddRange(($flowv, $flowh))
    $ok.Add_Click({
        $conndlg.Tag = $text.Text
        $text.Text = ''
    }.GetNewClosure())
    $conndlg
}

function GetProp($obj, $prop) {
    $obj.GetType().InvokeMember(
        $prop, [Reflection.BindingFlags]::GetProperty, $null, $obj, $null)
}

function IsSaneDate($dt) {
    $dt.Year -ge 1800 -and $dt.Year -lt 2200
}

function ByteProp($propname, $val, $add, $expand) {
    if ($val -is [Byte[]]) {
        $tname = $val.GetType().FullName
        if ($val.Length -eq 16) {
            &$add $propname "$tname (GUID)" (new-object Guid -a (,$val))
        }
        elseif ($val.Length -eq 28) {
            &$add $propname "$tname (SID)" (new-object Security.Principal.SecurityIdentifier -a (,$val,0))
        }
        elseif ('replUpToDateVector', 'repsFrom', 'repsTo' -contains $propname -and -not $expand) {
            &$add $propname $tname $val $true
        }
        else {
            &$add $propname $tname $([BitConverter]::ToString($val))
        }
        $true
    }
}

function I64Prop($propname, $val, $add, $expand) {
    if ($val -is [__ComObject]) {
        try {
            [int64] $hi = GetProp $val 'HighPart'
            [int64] $lo = GetProp $val 'LowPart'
            [int64] $qword = ($hi -shl 32) -bor $lo
            $valstr = [string]::Format('{0} = 0x{0:X16}', $qword)
            try {
                $dt = [DateTime]::FromFileTime($qword)
                if (IsSaneDate $dt) {
                    $valstr = [string]::Format("{0} = {1}", $valstr, $dt)
                }
            } catch { }
            try {
                if ('lockoutDuration', 'forceLogoff', 'lockOutObservationWindow',
                    'maxPwdAge', 'minPwdAge' -contains $propname `
                    -and $qword -ne 0x8000000000000000) {
                    $ts = [TimeSpan]::FromTicks([math]::abs($qword))
                    $valstr = [string]::Format("{0} = {1}", $valstr, $ts)
                }
            } catch { }
            &$add $propname 'ActiveDs.LargeInteger' $valstr
            $true
        } catch { }
    }
}

function AccessControlProp($propname, $val, $add, $expand) {
    if ($val -is [__ComObject]) {
        try {
            $valstr = [string]::Format(@'
AccessMask = {0} = 0x{0:X8}
AceFlags = {1} = 0x{1:X8}
AceType = {2} = 0x{2:X8}
Flags = {3} = 0x{3:X8}
InheritedObjectType = {4}
ObjectType = {5}
Trustee = {6}
'@,                $(GetProp $val 'AccessMask'),
                $(GetProp $val 'AceFlags'),
                $(GetProp $val 'AceType'),
                $(GetProp $val 'Flags'),
                $(GetProp $val 'InheritedObjectType'),
                $(GetProp $val 'ObjectType'),
                $(GetProp $val 'Trustee'))
            &$add $propname 'ActiveDs.AccessControlEntry' $valstr
            $true
        } catch { }
    }
}

function SecDescProp($propname, $val, $add, $expand) {
    if ($val -is [__ComObject]) {
        try {
            $valstr = [string]::Format(@'
Control = {0} = 0x{0:X8}
DaclDefaulted = {1}
Group = {2}
GroupDefaulted = {3}
Owner = {4}
OwnerDefaulted = {5}
Revision = {6}
SaclDefaulted = {7}
'@,                $(GetProp $val 'Control'),
                $(GetProp $val 'DaclDefaulted'),
                $(GetProp $val 'Group'),
                $(GetProp $val 'GroupDefaulted'),
                $(GetProp $val 'Owner'),
                $(GetProp $val 'OwnerDefaulted'),
                $(GetProp $val 'Revision'),
                $(GetProp $val 'SaclDefaulted'))
            &$add $propname 'ActiveDs.SecurityDescriptor' $valstr
            &$add "$propname.DiscretionaryAcl" 'ActiveDs.AccessControlEntry[]' `
                $(GetProp $val 'DiscretionaryAcl') $true
            $(GetProp $val 'SystemAcl') | %{
                AccessControlProp "$propname.SystemAcl" $_ $add
            }
            $true
        } catch { }
    }
}

function DNProp($propname, $val, $add, $expand) {
    if ($val -is [__ComObject]) {
        try {
            $valstr = [string]::Format("BinaryValue = {0}`nDNString = {1}",
                $(new-object Guid -a (,[byte[]]$(GetProp $val 'BinaryValue'))),
                $(GetProp $val 'DNString'))
            &$add $propname 'ActiveDs.DNWithBinary' $valstr
            $true
        } catch { }
    }
}

function IntProp($propname, $val, $add, $expand) {
    if ($val -is [int]) {
        &$add $propname $($val.GetType().FullName) `
            $([string]::Format('{0} = 0x{0:X8}', $val))
        $true
    }
}

function DateTimeProp($propname, $val, $add, $expand) {
    if ($val -is [DateTime] -and -not(IsSaneDate $val)) {
        &$add $propname $($val.GetType().FullName) `
            $([string]::Format('{0} = 0x{0:X16}', $val.ToFileTime()))
        $true
    }
}

function AddRowsFor($details, $propname, $val, $expand) {
    if ($val -is [Collections.IEnumerable] -and `
        $val -isnot [string] -and $val -isnot [byte[]]) {
        $val.GetEnumerator() | %{ AddRowsFor $details $propname $_ }
        return
    }
    $add = {
        param($pname, $typestr, $valstr, $delayload)
        if ($delayload) {
            $rindex = $details.Rows.Add($pname, $typestr, '[Double-click to show]')
            $details.Rows[$rindex].Tag = $valstr
        }
        else {
            $details.Rows.Add($pname, $typestr, $valstr)
        }
    }.GetNewClosure()
    if (ByteProp $propname $val $add $expand) { return }
    if (I64Prop $propname $val $add $expand) { return }
    if (SecDescProp $propname $val $add $expand) { return }
    if (AccessControlProp $propname $val $add $expand) { return }
    if (DNProp $propname $val $add $expand) { return }
    if (IntProp $propname $val $add $expand) { return }
    if (DateTimeProp $propname $val $add $expand) { return }
    &$add $propname $val.GetType().FullName $val `
        $($propname -eq 'gPLink' -and -not $expand)
}

function NewNode($name, $dn) {
    $node = new-object Windows.Forms.TreeNode -a $name -pr @{
        Tag = "LDAP://$dn"
    }
    [void] $node.Nodes.Add($(new-object Windows.Forms.TreeNode `
        -a 'Loading...' -pr @{ Name = 'LoadingNode' }))
    $node
}

function GetWindow() {
    $AddRowsFor = gi function:AddRowsFor
    $NewNode = gi function:NewNode
    $conndlg = GetConnDlg

    $connectcmd = new-object Windows.Forms.ToolStripMenuItem -pr @{
        ShortcutKeys = [Windows.Forms.Keys] 'Control, O'
        Text = '&Open'
    }
    $quitcmd = new-object Windows.Forms.ToolStripMenuItem -pr @{
        ShortcutKeys = [Windows.Forms.Keys] 'Alt, F4'
        Text = '&Quit'
    }
    $filemenu = new-object Windows.Forms.ToolStripMenuItem -pr @{
        Text = '&File'
    }
    $filemenu.DropDownItems.AddRange(($connectcmd, $quitcmd))
    $menu = new-object Windows.Forms.MenuStrip
    $menu.Items.AddRange(($filemenu))

    $window = new-object Windows.Forms.Form -pr @{
        ClientSize = new-object Drawing.Size -a 600, 400
        MainMenuStrip = $menu
        Text = 'AD Exploder'
    }
    $quitcmd.Add_Click({ $window.Close() }.GetNewClosure())

    $details = new-object Windows.Forms.DataGridView -pr @{
        AllowUserToAddRows = $false
        AllowUserToDeleteRows = $false
        AutoSizeRowsMode = [Windows.Forms.DataGridViewAutoSizeRowsMode]::AllCells
        AutoSizeColumnsMode = [Windows.Forms.DataGridViewAutoSizeColumnsMode]::AllCells
        Dock = [Windows.Forms.DockStyle]::Fill
        ReadOnly = $true
    }
    'Name', 'Type', 'Value' | %{ [void] $details.Columns.Add(
        $(new-object Windows.Forms.DataGridViewTextBoxColumn -pr @{
            HeaderText = $_
            Name = $_
        })
    )}
    $details.Columns['Value'].DefaultCellStyle = new-object Windows.Forms.DataGridViewCellStyle -pr @{
        WrapMode = [Windows.Forms.DataGridViewTriState]::True
    }
    $details.Add_CellDoubleClick({
        param($sender, $e)
        if ($e.ColumnIndex -eq 2) {
            $data = $details.Rows[$e.RowIndex].Tag
            if ($data -ne $null) {
                &$AddRowsFor $details $details[0,$e.RowIndex].Value $data $true
                $details.Rows.RemoveAt($e.RowIndex)
                $details.Sort($details.Columns['Name'], [ComponentModel.ListSortDirection]::Ascending)
            }
        }
    }.GetNewClosure())

    $tree = new-object Windows.Forms.TreeView -pr @{
        Dock = [Windows.Forms.DockStyle]::Fill
    }
    $tree.Add_AfterSelect({
        param($sender, $e)
        $adroot = new-object DirectoryServices.DirectoryEntry -a $e.Node.Tag
        $details.Rows.Clear()
        $adroot.Properties.GetEnumerator() | %{
            &$AddRowsFor $details $_.PropertyName $_.Value
            [Windows.Forms.Application]::DoEvents()
        }
        $details.Sort($details.Columns['Name'], [ComponentModel.ListSortDirection]::Ascending)
    }.GetNewClosure())
    $tree.Add_AfterExpand({
        param($sender, $e)
        if ($e.Node.Nodes.Count -eq 1 -and $e.Node.Nodes[0].Name -eq 'LoadingNode') {
            $adroot = new-object DirectoryServices.DirectoryEntry -a $e.Node.Tag
            $adroot.Children | %{
                [void] $e.Node.Nodes.Add($(NewNode $_.Name $_.distinguishedName))
                [Windows.Forms.Application]::DoEvents()
            }
            $e.Node.Nodes.RemoveByKey('LoadingNode')
        }
    })

    $Connect = {
        param($to)
        $node = &$NewNode $to $to
        $tree.Nodes.Add($node)
        $tree.SelectedNode = $node
    }.GetNewClosure()
    $connectcmd.Add_Click({
        if ($conndlg.ShowDialog() -eq [Windows.Forms.DialogResult]::OK) {
            &$Connect $conndlg.Tag
        }
    }.GetNewClosure())
    $window.Add_Shown({
        $connserv = [Environment]::GetEnvironmentVariable('logonserver')
        if ($connserv) {
            if ($connserv.StartsWith('\\')) {
                $connserv = $connserv.Substring(2)
            }
            &$Connect $connserv
        }
    }.GetNewClosure())

    $split = new-object Windows.Forms.SplitContainer -pr @{
        Dock = [Windows.Forms.DockStyle]::Fill
    }
    $split.Panel1.Controls.Add($tree)
    $split.Panel2.Controls.Add($details)
    $window.Controls.AddRange(($split, $menu))
    $window
}

[void] (GetWindow).ShowDialog()
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1 Answer 1

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Your code looks pretty good to me.

You can replace this:

[string]::Format('{0} = 0x{0:X8}', $val)

with this:

'{0} = 0x{0:X8}' -f $val

Empty "catch all" catch blocks are not a good idea:

    try {
       # ...
    } catch { }

They will hide all exception types indiscriminately, including ones that you might want to know about, which is not a good thing.

If you want to ignore a particular exception type, you should catch just that type (and ideally there should be comment saying why you are ignoring it):

    try {
       # ...
    } catch [SomeExceptionType] { 
       # Ignored because blah.
    }

This is a good thing to put at the top of scripts IMO:

Set-StrictMode -Version Latest

It will catch various programming mistakes that might otherwise pass unnoticed.

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