Generate_SAS_token

# This PowerShell script is part of video https://www.youtube.com/watch?v=BI7F4-4zfEY
#---------------------------------------------------------------------
# Date              : 28-09-2017
# Script name       : Generate_SAS_token.ps1
# Description       : This script will generate a SAS token from the
#                     Service Bus queue primary key.
#
# Created by        : Basic Cloud
# Extra module      :
# Copyright         : ©2017 Basic Cloud, all rights reserved.
# History           : Basic Cloud 20170928 Initial version
#---------------------------------------------------------------------

[Reflection.Assembly]::LoadWithPartialName("System.Web")| out-null

# Enter the information about the Service Bus
$URI="basiccloud.servicebus.windows.net/basiccloud/messages/head"
$Access_Policy_Name="RootManageSharedAccessKey"
$Access_Policy_Key="rd1sFC/Q1mySrpa8ygiJpyhd3wO5Q7yN5V0FycR0diU="

# Set the token expiration
$Expires=([DateTimeOffset]::Now.ToUnixTimeSeconds())+300


# Build the token
$SignatureString=[System.Web.HttpUtility]::UrlEncode($URI)+ "`n" + [string]$Expires

$HMAC = New-Object System.Security.Cryptography.HMACSHA256
$HMAC.key = [Text.Encoding]::ASCII.GetBytes($Access_Policy_Key)

$Signature = $HMAC.ComputeHash([Text.Encoding]::ASCII.GetBytes($SignatureString))

$Signature = [Convert]::ToBase64String($Signature)
$SASToken = "SharedAccessSignature sr=" + [System.Web.HttpUtility]::UrlEncode($URI) + "&sig=" + [System.Web.HttpUtility]::UrlEncode($Signature) + "&se=" + $Expires + "&skn=" + $Access_Policy_Name

# Output the value
$SASToken