Example usage of Custom Attributes

attr.ps1

. "$PSScriptRoot\attr_common.ps1"

class PowerShellExecutable : Executable
{
    [ExecutableArgument('File')]
    [string]$File

    [ExecutableArgument('Password', $true)]
    [string]$Password

    PowerShellExecutable([Hashtable]$parameters)
    {
        $type = $this.GetType()
        $properties = $type.GetProperties()

        foreach($property in $properties)
        {
            if($parameters.ContainsKey($property.Name) -and $parameters[$property.Name] -ne $null)
            {
                $property.SetValue($this, $parameters[$property.Name])
            }
        }
    }
}

function TestFunc
{
    [CmdletBinding()]
    param
    (
        [string]$Path,
        [string]$File,
        [string]$Password,
        [string]$Junk
    )

    [PowerShellExecutable]::new($PSBoundParameters)
}

TestFunc -Path "C:\windows\system32\WindowsPowerShell\v1.0\powershell.exe" -File "C:\Path\To\script.ps1" -Password "TestPass" -Junk "junk"

attr_common.ps1

class ExecutableArgument : System.Attribute
{
    [string]$Name
    [bool]$Sensitive

    [bool]$EncloseValueIfSpacesPresent = $true
    [ParameterStyle]$ParameterStyle
    [ParameterValueSeparator]$Separator

    [object]$Value

    ExecutableArgument([string]$name)
    {
        $this.Name = $name
        $this.Sensitive = $false
    }

    ExecutableArgument([string]$name, [bool]$sensitive)
    {
        $this.Name = $name
        $this.Sensitive = $sensitive
    }

    ExecutableArgument([string]$name, [bool]$sensitive, [bool]$encloseValue, [ParameterStyle]$style, [ParameterValueSeparator]$separator)
    {
        $this.Name = $name
        $this.Sensitive = $sensitive
        $this.EncloseValueIfSpacesPresent = $true
        $this.ParameterStyle = $style
        $this.Separator = $separator
    }
}

enum ParameterStyle
{
    Slash
    Backslash
    Dash
    DoubleDash
}

enum ParameterValueSeparator
{
    Space
    Colon
}

class Executable
{
    [string]$Path 

    [void] Invoke()
    {
        Invoke-Expression -Command $this.GetInvokeString()
    }

    [string] GetInvokeString()
    {
        $cmd = "& $($this.Path) "
        $params = @()
        foreach($param in $this.GetArguments())
        {
            $cmdParam = switch($param.ParameterStyle)
            {
                Slash { '/' }
                Backslack { '\' }
                Dash { '-' }
                DoubleDash { '--' }
            }

            $cmdParam += $param.Name
            
            $cmdParam += switch($param.Separator)
            {
                Space { ' ' }
                Colon { ':' }
            }

            if($param.EncloseValueIfSpacesPresent -eq $true -and $param.Value -match '\s')
            {
                $cmdParam += '"'
                $cmdParam += $param.Value
                $cmdParam += '"'
            }
            else 
            {
                $cmdParam += $param.Value
            }

            $params += $cmdParam
        }

        $cmd += $params -join ' '
        return $cmd
    }

    [ExecutableArgument[]] GetArguments()
    {
        $type = $this.GetType()
        $properties = $type.GetProperties()

        $result = @()

        foreach($property in $properties)
        {

            $attr = [System.Attribute]::GetCustomAttribute($property, [ExecutableArgument])
            if($attr -ne $null)
            {
                $attr.Value = $property.GetValue($this)
                $result += $attr
            }
        }

        return $result
    }
}