Private/Parse-JWTToken.ps1
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function Parse-JWTtoken { <# .DESCRIPTION Decodes a JWT token. This was taken from link below. Thanks to Vasil Michev. .LINK https://www.michev.info/Blog/Post/2140/decode-jwt-access-and-id-tokens-via-powershell #> [cmdletbinding()] param( [Parameter(Mandatory = $True)] [string]$Token ) #Validate as per https://tools.ietf.org/html/rfc7519 #Access and ID tokens are fine, Refresh tokens will not work if (-not $Token.Contains(".") -or -not $Token.StartsWith("eyJ")) { Write-Error "Invalid token" -ErrorAction Stop } #Header $tokenheader = $Token.Split(".")[0].Replace('-', '+').Replace('_', '/') #Fix padding as needed, keep adding "=" until string length modulus 4 reaches 0 while ($tokenheader.Length % 4) { Write-Verbose "Invalid length for a Base-64 char array or string, adding =" $tokenheader += "=" } Write-Verbose "Base64 encoded (padded) header: $tokenheader" #Convert from Base64 encoded string to PSObject all at once Write-Verbose "Decoded header:" $header = ([System.Text.Encoding]::ASCII.GetString([system.convert]::FromBase64String($tokenheader)) | convertfrom-json) #Payload $tokenPayload = $Token.Split(".")[1].Replace('-', '+').Replace('_', '/') #Fix padding as needed, keep adding "=" until string length modulus 4 reaches 0 while ($tokenPayload.Length % 4) { Write-Verbose "Invalid length for a Base-64 char array or string, adding =" $tokenPayload += "=" } Write-Verbose "Base64 encoded (padded) payoad: $tokenPayload" $tokenByteArray = [System.Convert]::FromBase64String($tokenPayload) $tokenArray = ([System.Text.Encoding]::ASCII.GetString($tokenByteArray) | ConvertFrom-Json) #Converts $header and $tokenArray from PSCustomObject to Hashtable so they can be added together. #I would like to use -AsHashTable in convertfrom-json. This works in pwsh 6 but for some reason Appveyor isnt running tests in pwsh 6. $headerAsHash = @{} $tokenArrayAsHash = @{} $header.psobject.properties | ForEach-Object { $headerAsHash[$_.Name] = $_.Value } $tokenArray.psobject.properties | ForEach-Object { $tokenArrayAsHash[$_.Name] = $_.Value } $output = $headerAsHash + $tokenArrayAsHash Write-Output $output } |