From: Michael <invalid@...>
Date: 2005-08-31T13:46:23+09:00
Subject: More elegant replacement for global variables

I'm playing around with a ruby app using XML-RPC. Currently I'm using
global variables so I can create multiple objects without having to log
in for each and every object.

class Base
	def initialize(user, pass)
		$user, $pass = user, pass
	end

	def login()
		$client = XMLRPC::Client.new(...)
		$sessionid = $client.call("xmlrpc.method", $user, $pass)
		return $sessionid
	end
end

Derived classes look like this:

class Object1 < Base
	def initialize()
		if not $sessionid then self.login end
	end
end

This way I can log in once with the first object created without having
to log in each time. However, this seems inelegant to me. Is there a
more elegant, or just more rubyish, way of doing this? Also, I'd have
potential problems if I wanted to log on as multiple users.

Would it make more sense just to pass around an instance of the Base object:

class Object2
	def initialize(xmlrpc_client)
		if not xmlrpc_client.sessionid then xmlrpc_client.login	
	end

	def call_xmlrpc_method(method, params)
		results = xmlrpc_client.call(method, params)
		return results
	end
end

xmlrpc_client = Base.new
o2 = Object2.new(xmlrpc_client)

Pro: no global variables. Con: coupling between Object2 and Base classes.
--Michael