Custom ActiveDirectory Filters

One of my favorite things about powershell is it’s flexibility. Powershell can let you do so much. The Pipeline is Awesome ( but thats another rant\post). The focus of this post wil be about creating wrapper functions to extend the functionality of existing Cmdlets. By defining your own function and following a few standard practices you can make your very own cmdlet, and make it look and operate like a compiled cmdlet

In this post we’ll discuss the Get-ADUser cmdlet from the Active Directory module. This cmdlet is allows you to get one or more user objects.

    Set-Location 'src'

Gets one or more Active Directory users.

The Get-ADUser cmdlet takes a Now you may think, “Whats wrong with Get-ADUser?”

Based on the Help, …. You are using Get-Help, aren’t you!! It says that Get-ADUser can be used in three ways. You can get a single AD User by identity

    Get-ADUser -Identity {GUID}

You can also search for a single or multiple users based on filters; You can filter using the PowerShell Expression language

    Get-ADUser -Filter "Enabled=True"

You can filter using a LDAPquery string

    Get-ADUser -LDAPFilter '{SurName = "K*"}'

Now these methods are great but they are not the way my brain works. I want to say… Get me Peter Smith’s AD account. or more likely… I want John’s account… John who?… You know John M…. OH HIM!!!

So lets look at how can can solve both of these scenarios.

Lets start by defining an advanced function

    Function Get-MyADUser {}
        [CmdletBinding()]
        Param
        (
            [Parameter(Position = 0)]
            [String] $LastName,
            [Parameter()]
            [String] $FirstName,
            [Parameter()]
            [String[]] $properties,
            [Parameter()]
            [String] $Server = $env:USERDOMAIN,
            [Parameter()]
            [Switch] $Groups
        )

        Begin
        {
            If (! (Get-Command Get-ADDomain -ErrorAction SilentlyContinue) ) {
                Write-Warning "ActiveDirectory Module Not Installed...."
                Break
            }
            
            $Props = @("SamaccountName", "GivenName", "SurName")
            If ($Properties) {
                Write-Verbose "Adding additional Properties to DefaultProps..."
            Foreach ($prop in $properties) {
                    $Props += $Prop
                }
            }
            If ($Groups) {
                $DefProps = $Props
                $Props += @(,"MemberOf")
            }

        }
        Process
        {

            $count = 0
            $LDAP_FirstName = ""
            $LDAP_LastName = ""

            If ($firstname) {
                $LDAP_FirstName = "(GivenName=$firstname)"
                $count++
            }

            If ($lastname) {
                $LDAP_LastName = "(SN=$lastname)"
                $count++
            }

            IF ($count -gt 1) {
                $ldapQuery = "(`&$($LDAP_FirstName)$($LDAP_LastName) )"
            } Else {
                $ldapQuery = "$($LDAP_FirstName)$($LDAP_LastName)"
            }
    
        
            $MyParms = @{ 'LDAPFilter' = "$ldapQuery" }
        
            If ($Groups) {
                $users = Get-ADUser @MyParms -Properties $Props -Server $Server -Verbose | Select -Property $Props
                    $Users | % { 
                        $GroupProps = @(,"GroupName")
                        $GroupProps += $DefProps 
                        $curr = $_ 
                        Add-Member -InputObject $Curr -MemberType NoteProperty -Name "GroupName" -Value "DEFL"
                        $_.memberof | %{ 
                            $curr.GroupName = $_
                            $curr | Select $GroupProps
                        }
                        $curr = $null
                    }
                

            } else {
                Get-ADUser @MyParms -Properties $Props -Server $Server -Verbose | Select $Props
            }

        }
        End
        {
        }
    }

Get-myADUser -FirstName 

Get-MyADUser [[-LastName] <string>] [-FirstName <string>] [-properties <string[]>] [-Server <string>] [-Groups] [<CommonParameters>]