PowerShell function to generate signed string for WAS Authorization header

was-generate-authheaderstring

function Generate-AuthString
{
	param(
		 [string]$url
		,[string]$accountName
		,[string]$accountKey
		,[string]$requestUtcTime
	) 
	
		
	$uri = New-Object System.Uri -ArgumentList $url
	
	$authString =   "GET$([char]10)$([char]10)$([char]10)$([char]10)$([char]10)$([char]10)$([char]10)$([char]10)$([char]10)$([char]10)$([char]10)$([char]10)"
	$authString += "x-ms-date:" + $requestUtcTime + "$([char]10)"
	$authString += "x-ms-version:2011-08-18" + "$([char]10)"
	$authString += "/" + $accountName + $uri.AbsolutePath + "$([char]10)"
	$authString += "comp:list$([char]10)"
	$authString += "include:snapshots,uncommittedblobs,metadata$([char]10)"	
	$authString += "restype:container$([char]10)"
	$authString += "timeout:90"
	
	$dataToMac = [System.Text.Encoding]::UTF8.GetBytes($authString)

	$accountKeyBytes = [System.Convert]::FromBase64String($accountKey)

	$hmac = new-object System.Security.Cryptography.HMACSHA256((,$accountKeyBytes))
	[System.Convert]::ToBase64String($hmac.ComputeHash($dataToMac))
}