Private/Get-IDNWTokenDetails.ps1
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<# .SYNOPSIS Decode a JWT Access Token and convert to a PowerShell Object. .DESCRIPTION Decode a JWT Access Token and convert to a PowerShell Object. .PARAMETER token The JWT Access Token to decode and udpate with expiry time and time to expiry .EXAMPLE Get-JWTDetails -token $myAccessToken .INPUTS System.String .OUTPUTS System.Object .LINK https://blog.darrenjrobinson.com .LINK https://blog.darrenjrobinson.com/jwtdetails-powershell-module-for-decoding-jwt-access-tokens-with-readable-token-expiry-time/ #> function Get-IDNWTokenDetail { [CmdletBinding()] param ( [Parameter()] [String] $Token ) if (!$token.Contains(".") -or !$token.StartsWith("eyJ")) { throw "Invalid token" } # Token foreach ($i in 0..1) { $data = $token.Split('.')[$i].Replace('-', '+').Replace('_', '/') switch ($data.Length % 4) { 0 { break } 2 { $data += '==' } 3 { $data += '=' } } } $decodedToken = [System.Text.Encoding]::UTF8.GetString([convert]::FromBase64String($data)) | ConvertFrom-Json Write-Debug "JWT Token:" Write-Debug $decodedToken # Signature foreach ($i in 0..2) { $sig = $token.Split('.')[$i].Replace('-', '+').Replace('_', '/') switch ($sig.Length % 4) { 0 { break } 2 { $sig += '==' } 3 { $sig += '=' } } } Write-Debug "JWT Signature:" Write-Debug $sig $decodedToken | Add-Member -Type NoteProperty -Name "sig" -Value $sig # Convert Expiry time to PowerShell DateTime $orig = (Get-Date -Year 1970 -Month 1 -Day 1 -hour 0 -Minute 0 -Second 0 -Millisecond 0) $timeZone = Get-TimeZone $utcTime = $orig.AddSeconds($decodedToken.exp) $offset = $timeZone.GetUtcOffset($(Get-Date)).TotalMinutes #Daylight saving needs to be calculated $localTime = $utcTime.AddMinutes($offset) # Return local time, $decodedToken | Add-Member -Type NoteProperty -Name "expiryDateTime" -Value $localTime # Time to Expiry $timeToExpiry = ($localTime - (get-date)) $decodedToken | Add-Member -Type NoteProperty -Name "timeToExpiry" -Value $timeToExpiry return $decodedToken } |