As is often the case, when working on a project I end up needing some sub-task done and search the web to see if someone have done it before. In this particular instance I couldn’t find any ready-made solutions for PowerShell, but I did find that someone had written a couple of functions in c# that did exactly what I needed. Luckily, translating from c# to PowerShell isn’t that hard, so I thought I’d share the functions I wrote (translated) with you.
NOTE! I take no credit for these functions, other than the fact I translated them from c#. The full credit goes to Jonathan Taylor.
These functions lets you decode and encode to and from Base64 Url.
| function Invoke-Base64UrlDecode { | |
| <# | |
| .SYNOPSIS | |
| .DESCRIPTION | |
| .NOTES | |
| http://blog.securevideo.com/2013/06/04/implementing-json-web-tokens-in-net-with-a-base-64-url-encoded-key/ | |
| Author: Øyvind Kallstad | |
| Date: 23.03.2015 | |
| Version: 1.0 | |
| #> | |
| [CmdletBinding()] | |
| param ( | |
| [Parameter(Position = 0, Mandatory)] | |
| [string] $Argument | |
| ) | |
| $Argument = $Argument.Replace('–', '+') | |
| $Argument = $Argument.Replace('_', '/') | |
| switch($Argument.Length % 4) { | |
| 0 {break} | |
| 2 {$Argument += '=='; break} | |
| 3 {$Argument += '='; break} | |
| DEFAULT {Write-Warning 'Illegal base64 string!'} | |
| } | |
| Write-Output $Argument | |
| } |
| function Invoke-Base64UrlEncode { | |
| <# | |
| .SYNOPSIS | |
| .DESCRIPTION | |
| .NOTES | |
| http://blog.securevideo.com/2013/06/04/implementing-json-web-tokens-in-net-with-a-base-64-url-encoded-key/ | |
| Author: Øyvind Kallstad | |
| Date: 23.03.2015 | |
| Version: 1.0 | |
| #> | |
| [CmdletBinding()] | |
| param ( | |
| [Parameter(Position = 0, Mandatory)] | |
| [byte[]] $Argument | |
| ) | |
| $output = [System.Convert]::ToBase64String($Argument) | |
| $output = $output.Split('=')[0] | |
| $output = $output.Replace('+', '–') | |
| $output = $output.Replace('/', '_') | |
| Write-Output $output | |
| } |
