Functions/Show-DecodedJwt.ps1
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function Show-DecodedJwt { <# .SYNOPSIS Displays a JSON Web Token header and payload in color. .DESCRIPTION Displays a JSON Web Token header and payload in color for easy viewing. Note that this advanced function is not meant to send any data and/or objects down the pipeline. .PARAMETER JsonWebToken The JSON Web Token to be decoded and displayed. .EXAMPLE $jwt = "eyJ0eXAiOiJKV1QiLCJhbGciOiJSUzI1NiIsIng1dCI6IjJ5Q3Zabms3azhXNjZ3UjJMWFI5V0Nzd2hBYyIsImtpZCI6IjJ5Q3Zabms3azhXNjZ3UjJMWFI5V0Nzd2hBYyJ9.eyJpYXQiOjE2MTgyNTAzODksIm5iZiI6MTYxODI1MDM4OSwiZXhwIjoxNjE4MjU1MTg5LCJzdWIiOiJ0b255In0.X-RZm-3Hto5U-8Q-Wp1ggqWTFPkO5-Cz9lzoKsH5-1RR9GOrGPuWn-bjIv1YJ46h5Bw-KpiX-dOS47TAq2A0BWdAwczLVA6pzha1WswkT_u3cO1_KSoOjD9qFLjCgk-ns7A48iXpNcOoPBFXgfx8G0rRK68sSnokJ7N2NH-YNUOjg3U7DNJ_-iz8WZ5dNlOvpDsTy0BHMX-lho18sUmakUNpadJr-oD7BXIp--Z57UERBFibppaoxseYRo3VfmhgHibTxP-39mcxU6sH9a99fEEt80hj4w6rZobRxZV-pFPS22B8TBAfVf8L9faMLaXmgV7xtQohqQZgL6oKdJzFPQ" $jwt | Show-DecodedJwt Displays a decoded JSON Web Token with the header in red, the body in cyan/blue, and a green placeholder for the signature. .INPUTS System.String A string is received by the JsonWebToken parameter. .OUTPUTS None This cmdlet returns no output. It sends the objects to the host. The host displays the objects this cmdlet sends to it. .LINK https://tools.ietf.org/html/rfc7519 #> [CmdletBinding()] [Alias('sjwt')] [OutputType([System.Boolean])] Param ( [Parameter(Mandatory = $true, ValueFromPipeline = $true, Position = 0)] [ValidateLength(16, 8192)][Alias("JWT", "Token")][String]$JsonWebToken ) BEGIN { $decodeExceptionMessage = "Unable to decode JWT." $ArgumentException = New-Object -TypeName ArgumentException -ArgumentList $decodeExceptionMessage } PROCESS { [bool]$hasValidJwtStructure = Test-JwtStructure -JsonWebToken $JsonWebToken if (-not($hasValidJwtStructure)) { Write-Error -Exception $ArgumentException -Category InvalidArgument -ErrorAction Stop } $arrayCellCount = $JsonWebToken.Split(".") | Measure-Object | Select-Object -ExpandProperty Count if ($arrayCellCount -lt 3) { $decodeExceptionMessage = "Unable to decode JWT." $ArgumentException = New-Object -TypeName ArgumentException -ArgumentList $decodeExceptionMessage Write-Error -Exception $ArgumentException -Category InvalidArgument -ErrorAction Stop } # Get the header and payload as hashtables: $header = Get-JsonWebTokenHeader -JsonWebToken $JsonWebToken $payload = Get-JsonWebTokenPayload -JsonWebToken $JsonWebToken # Serialize the hashtables into JSON and output via Write-Host $header | ConvertTo-Json | Write-Host -ForegroundColor Red -NoNewline Write-Host -Object "." -ForegroundColor Yellow -NoNewline $payload | ConvertTo-Json | Write-Host -ForegroundColor Cyan -NoNewline Write-Host -Object "." -ForegroundColor Yellow -NoNewline if (($JsonWebToken.Split(".")[2] -gt 12)) { Write-Host -Object "[Signature]" -ForegroundColor Green } } } |