Generating an Azure SAS token, reading from Service Bus, using Ruby

	class ServiceBusWrapper
	def read_service_bus_event
	Faraday.delete("#{ service_bus_queue_endpoint }/messages/head", {}, service_bus_headers)
	end
	private
	def service_bus_headers
	{
	'Authorization' => service_bus_sas_token,
	'Content-Type' => 'application/atom+xml;type=entry;charset=utf-8',
	}
	end
	def service_bus_sas_token
	encoded_uri = CGI.escape(service_bus_queue_endpoint)
	expiry = 1.minute.from_now.to_i.to_s # Decide on this expiry yourself.
	string_to_sign = "#{ encoded_uri }\n#{ expiry }"
	signed_string = OpenSSL::HMAC.digest('sha256', sas_key_value, string_to_sign)
	signature = CGI.escape(Base64.strict_encode64(signed_string))
	"SharedAccessSignature sig=#{ signature }&se=#{ expiry }&skn=#{ sas_key_name }&sr=#{ encoded_uri }"
	end
	def service_bus_queue_endpoint
	'https://your-service-bus-domain.servicebus.windows.net/your-queue-name'
	end
	def sas_key_name
	'YourSharedAccessPolicyNameHere'
	end
	def sas_key_value
	ENV['sas_key_value']
	end
	end