Public/ConvertFrom-Base64ToString.ps1

<#
    .SYNOPSIS
        Converts a base64 encoded string to a string.
 
    .DESCRIPTION
        Converts a base64 encoded string to a string.
 
    .PARAMETER String
        A Base64 Encoded String
 
    .PARAMETER Encoding
        The encoding to use for conversion.
        Defaults to UTF8.
        Valid options are ASCII, BigEndianUnicode, Default, Unicode, UTF32, UTF7, and UTF8.
 
    .EXAMPLE
        ConvertFrom-Base64ToString -String 'QSBzdHJpbmc='
 
        A string
 
    .EXAMPLE
        ConvertTo-Base64 -String 'A string','Another string'
 
        QSBzdHJpbmc=
        QW5vdGhlciBzdHJpbmc=
 
    .EXAMPLE
        'QSBzdHJpbmc=' | ConvertFrom-Base64ToString
 
        A string
 
    .EXAMPLE
        'QSBzdHJpbmc=','QW5vdGhlciBzdHJpbmc=' | ConvertFrom-Base64ToString
 
        A string
        Another string
 
    .OUTPUTS
        [String[]]
 
    .LINK
        http://convert.readthedocs.io/en/latest/functions/ConvertFrom-Base64ToString/
#>

function ConvertFrom-Base64ToString
{
    [CmdletBinding(HelpUri = 'http://convert.readthedocs.io/en/latest/functions/ConvertFrom-Base64ToString/')]
    [OutputType('String')]
    param
    (
        [Parameter(
            Mandatory = $true,
            ValueFromPipeline = $true,
            ValueFromPipelineByPropertyName = $true)]
        [ValidateNotNullOrEmpty()]
        [String[]]
        $String,

        [ValidateSet('ASCII', 'BigEndianUnicode', 'Default', 'Unicode', 'UTF32', 'UTF7', 'UTF8')]
        [String]
        $Encoding = 'UTF8',

        [Parameter(Mandatory = $false)]
        [Switch]
        $Decompress
    )

    begin
    {
        $userErrorActionPreference = $ErrorActionPreference
    }

    process
    {
        foreach ($s in $String)
        {
            try
            {
                $bytes = [System.Convert]::FromBase64String($s)

                if ($Decompress)
                {
                    ConvertFrom-CompressedByteArrayToString -ByteArray $bytes -Encoding $Encoding
                }
                else
                {
                    [System.Text.Encoding]::$Encoding.GetString($bytes)
                }
            }
            catch
            {
                Write-Error -ErrorRecord $_ -ErrorAction $userErrorActionPreference
            }
        }
    }
}