For loading users into an ldap directory from a CSV file. Will create new users and update attributes as needed on existing users.

LoadUsersIntoLdap.ps1

#Requires -Module ActiveDirectory
[CmdletBinding()]
param ($users_file, [switch]$WhatIf)

if (-not $users_file) {
    Write-Warning "Must pass file name as `$users_file"
    return 1
}

Write-Host -ForegroundColor Cyan $users_file

cd $(Split-Path -parent "$($MyInvocation.MyCommand.Definition)")

function ToPages {
    param (
        [Parameter(ValueFromPipeline=$true, Position=0)]
        [object]$InputObject,
        [Parameter(Mandatory=$true, Position=1)]
        [int]$PageSize)
    begin {
        $book = New-Object System.Collections.Generic.List[object]
        $page = @()
    }
    process {
        $page += $InputObject        
        if ($page.Count -ge $PageSize) {
            $book.Add($page)
            $page = @()
        }
    }
    end {
        $book.Add($page)
        $book.ToArray()
    }
}

$ldap_server = 'localhost:389'
$ldap_root = 'DC=McAttributes,DC=or,DC=gov'
$ldap_active_root = 'CN=Users,DC=McAttributes,DC=or,DC=gov'

$ldap_property_map = @{
    'name'="aadId"
    'displayName'="displayName"
    'employeeId'="employeeId"
    'givenName'="givenName"
    'surname'="surname"
    'comment'="pronouns"
    'personalTitle'="suffix"
}

$name_attribute = $ldap_property_map['name']

$ldap_properties = @($ldap_property_map.Keys)
$user_properties = @($ldap_property_map.Values)


## Load CSV
Write-Progress -Activity 'Provisioning LDS Users' -CurrentOperation 'Importing user records'
$users = Import-Csv $users_file
$users_hashset = New-Object System.Collections.Generic.HashSet[string]
$users | % { $users_hashset.Add($_.($ldap_property_map['name'])) } | Out-Null
Write-Host "Loaded $($users.Count) user records"

## Load active LDS users
Write-Progress -Activity 'Provisioning LDS Users' -CurrentOperation 'Loading LDS current users'
$active_users = @(Get-ADUser -Server $ldap_server -SearchBase $ldap_active_root -LDAPFilter "(objectClass=person)" -Properties $ldap_properties)
$active_hashset = New-Object System.Collections.Generic.HashSet[string]
$active_users | % { $active_hashset.Add($_.Name) } | Out-Null
Write-Host "Loaded $($active_users.Count) active LDS user records"

## Compute new users
Write-Progress -Activity 'Provisioning LDS Users' -CurrentOperation 'Resolving new users'
$new_users = @($users | ? { -not $active_hashset.Contains($_.($ldap_property_map['name'])) })
Write-Host "New user records $($new_users.Count)"


## Create users
Write-Host "Creating new users"
filter Percent { param ([int]$count=0, [int]$total=0) if ($total -eq 0) { return 0 } [Math]::Min(100,[Math]::Round((($count/$total) * 100))) }
$count = 0
if ($new_users) {
foreach ($user in $new_users) {
    $count++
    Write-Progress -Activity 'Provisioning LDS Users' -CurrentOperation 'Creating user accounts' -PercentComplete (Percent $count $new_users.Count)
    
    $params = @{
        'WhatIf'=$WhatIf
    }
    if ($user.($ldap_property_map['displayName'])) {
        $params.Add('DisplayName', $user.($ldap_property_map['displayName']))
    }
    if ($user.($ldap_property_map['givenName'])) {
        $params.Add('GivenName', $user.($ldap_property_map['givenName']))
    }
    if ($user.($ldap_property_map['surname'])) {
        $params.Add('Surname', $user.($ldap_property_map['surname']))
    }

    New-ADUser -Server $ldap_server -Path $ldap_active_root `
               -Name $user.$name_attribute `
               -Verbose `
               @params
}
}
else {
    Write-Host "No new users to add"
}

## Reload active user objects
if ($new_users.Count -gt 0) {
    Write-Progress -Activity 'Provisioning LDS Users' -CurrentOperation 'Refreshing active user list'
    $active_users = @(Get-ADUser -Server $ldap_server -SearchBase $ldap_active_root -LDAPFilter "(objectClass=user)" -Properties $ldap_properties)
    Write-Host "Loaded $($active_users.Count) active LDS user records"
}
$active_user_ht = @{}
$active_users | % { $active_user_ht.Add($_.Name, $_) } | Out-Null
Write-Progress -Activity 'Provisioning LDS Users' -CurrentOperation 'Refreshing active user list' -Completed

## Update Attributes
function CleanChars {
    param ([string]$InputString)
    if ([String]::IsNullOrEmpty($InputString)) { return $InputString }

    $sb = New-Object System.Text.StringBuilder ($InputString.Length)
    foreach ($c in $InputString.ToCharArray()) {
        switch ($c) {
            '[' { } #do nothing
            ']' { } #do nothing
            '*' { } #do nothing           
            '?' { } #do nothing
            default { $sb.Append($c) | Out-Null }
        }
    }

    return $sb.ToString()
}

$count = 0
foreach ($user in $users) {
    $count++
    Write-Progress -Activity 'Provisioning LDS Users' -CurrentOperation 'Updating user attributes' -PercentComplete (Percent $count $users.Count)
    $lds_user = $active_user_ht[$user.$name_attribute]
    if ($lds_user) {
        $params = @{
                    'Verbose'=$true
                    'WhatIf'=$WhatIf
                    'Server'=$ldap_server
                    }
        $replace_vals = @{}
        $set_vals = @{}
        $clear_vals = @()
                
        foreach ($p in $ldap_properties) {
            $up = $ldap_property_map[$p]
            if ($user.$up -notlike (CleanChars $lds_user.$p)) {
                
                # destination has value, source doesn't. Clear destination.
                if (-not $user.$up -and $lds_user.$p) {
                    $clear_vals += $ldap_property_map[$p]
                }
                elseif ($user.$up -and ($lds_user.$p)) {
                    $replace_vals.Add($p, $user.$up)
                }
                elseif ($user.$up -and (-not $lds_user.$p)) {
                    $set_vals.Add($p, $user.$up)
                }
                else {
                    Write-Warning "No match for ldap property: $p to user property: $up"
                }
            }
        }
        
        if ($replace_vals.Count -gt 0) { $params.Add("Replace", $replace_vals) }
        if ($set_vals.Count -gt 0)     { $params.Add("Add", $set_vals) }
        if ($clear_vals)               { $params.Add("Clear", $clear_vals) }
        if ($params.Count -gt 3) {
            $lds_user | Set-ADObject @params
        }
    }
    else {
        Write-Warning "User: $($user.$name_attribute) not found, skipping..."
    }
}