ForestManagement

1.1.16

internal/functions/Import-LdifFile.ps1

function Import-LdifFile
{
    <#
    .SYNOPSIS
        Parses an LDIF file and returns the changes it applies.
     
    .DESCRIPTION
        Parses an LDIF file and returns the changes it applies.
        Note: schemaupdatenow commands are skipped.
     
    .PARAMETER Path
        The path to the LDIF file to parse.
     
    .EXAMPLE
        PS C:\> Import-LdifFile -Path $ldifFile
 
        Parses the ldif file and returns changes it applies.
    #>
    [CmdletBinding()]
    param (
        [string]
        $Path
    )
    
    begin
    {
        #region Utility Functions
        function Resolve-AttributeName
        {
            [OutputType([string])]
            [CmdletBinding()]
            param (
                [string]
                $Name
            )
            
            switch ($Name)
            {
                'dn' { 'DistinguishedName' }
                default { $Name }
            }
        }
        function Resolve-AttributeValue
        {
            [Diagnostics.CodeAnalysis.SuppressMessageAttribute("PSUseOutputTypeCorrectly", "")]
            [CmdletBinding()]
            param (
                [string]
                $Value,
                
                [bool]
                $IsBase64,
                
                [string]
                $AttributeName
            )
            
            if ($IsBase64)
            {
                switch ($AttributeName)
                {
                    'schemaIDGUID' {
                        [PSCustomObject]@{
                            Guid = [System.Guid]::new([System.Convert]::FromBase64String($Value))
                            GuidData = [System.Convert]::FromBase64String($Value)
                        }
                    }
                    'attributeSecurityGUID' {
                        [PSCustomObject]@{
                            Guid = [System.Guid]::new([System.Convert]::FromBase64String($Value))
                            GuidData = [System.Convert]::FromBase64String($Value)
                        }
                    }
                    'omObjectClass' {
                        [System.Convert]::FromBase64String($Value)
                    }
                    default { [System.Text.Encoding]::UTF8.GetString([System.Convert]::FromBase64String($Value)) }
                }
            }
            else
            {
                if ($Value -eq "TRUE") { return $true }
                if ($Value -eq "FALSE") { return $false }
                if ($Value -eq "") { return '' }
                if ($null -ne ($Value -as [int])) { return ($Value -as [int]) }
                $Value
            }
        }
        #endregion Utility Functions
        
        $lines = Get-Content -Path $Path
        $currentObject = @{ }
        $lastKey = ''
        $orderCount = 0
    }
    process
    {
        $isBase64 = $false
        foreach ($line in $lines)
        {
            if (-not $line) { continue }
            if ($line -like '#*') { continue }
            if ($line -like 'dn:*')
            {
                if (($currentObject.Keys.Count -gt 1) -and ($currentObject['replace'] -ne 'schemaupdatenow')) { [pscustomobject]$currentObject }
                $currentObject = @{
                    PSTypeName          = 'ForestManagement.Schema.Ldif.Setting'
                    DistinguishedName = ($line -replace '^dn:', '').Trim() -replace ',DC=X$' -replace ',CN=Schema,CN=Configuration$'
                    FM_OrderCount     = $orderCount
                }
                $orderCount++
                $lastKey = 'DistinguishedName'
                continue
            }
            if ($line -match '^([^:]+):(?<colon>:*) (.*)$')
            {
                $isBase64 = $matches['colon'] -eq ':'
                $attributeName = Resolve-AttributeName -Name $matches[1]
                $attributeValue = Resolve-AttributeValue -Value $matches[2] -IsBase64 $isBase64 -AttributeName $attributeName
                # Prevent duplicate object classes - top is redundant and not listed in AD
                if (($attributeName -eq 'ObjectClass') -and ($attributeValue -eq 'Top')) { continue }
                if ($currentObject.ContainsKey($attributeName))
                {
                    $values = @($currentObject[$attributeName])
                    $values += $attributeValue
                    $currentObject[$attributeName] = $values
                }
                else
                {
                    $currentObject[$attributeName] = $attributeValue
                }
                $lastKey = $attributeName
            }
            # Handle value continuation on the next line
            # Values break line when exceeding a total width of 80 characters
            elseif ($line -match '^ (.+)$')
            {
                $currentObject[$lastKey] = $currentObject[$lastKey] + (Resolve-AttributeValue -Value $matches[1] -IsBase64 $isBase64 -AttributeName $lastKey)
            }
        }
    }
    end
    {
        # Process last item
        if ($currentObject.Keys.Count -gt 0)
        {
            if ($currentObject['replace'] -ne 'schemaupdatenow') { [pscustomobject]$currentObject }
        }
    }
}