Hey Everybody - I Found a Use for a Singleton

Lightning talk given @ WindyCityRails 2015 about what I found a decent use of a Singleton would be in a Ruby library.

Transcript

1. HEY EVERYBODY I FOUND A USE FOR A SINGLETON
2. WHAT'S A SINGLETON?
3. RESTRICTS INSTANTIATION OF A CLASS TO ONE OBJECT
4. THERE CAN BE ONLY ONE
5. WHEN EXACTLY ONE OBJECT IS NEEDED
6. require 'singleton'
7. STATE/CONFIG OBJECTS
8. require 'singleton' module AppName module PaymentGatewayName class Configuration include Singleton attr_accessor :base_uri, :database_name, :database_type, :server_name, :username, :password end end end
9. Configuration.new
10. Whoops! — DHH
11. Configuration.instance
12. module AppName module PaymentGatewayName module API def self.configure yield(configuration) if block_given? end def self.configuration Configuration.instance end def self.connection url = configuration.base_url @connection ||= Faraday.new(url) end end end end
13. module AppName module PaymentGatewayName module API ... def self.configuration Configuration.instance end ... end end end
14. module AppName module PaymentGatewayName module API def self.configure yield(configuration) if block_given? end ... end end end
15. module AppName module PaymentGatewayName module API ... def self.connection url = configuration.base_url @connection ||= Faraday.new(url) end end end end
16. module AppName module PaymentGatewayName module API def self.configure yield(configuration) if block_given? end def self.configuration Configuration.instance end def self.connection url = configuration.base_url @connection ||= Faraday.new(url) end end end end
17. AppName::PaymentGatewayName::API.configure do |config| config.base_uri = ENV.fetch("PAYMENTGATEWAY_BASE_URI") config.database_name = ENV.fetch("PAYMENTGATEWAY_DATABASE_NAME") config.database_type = ENV.fetch("PAYMENTGATEWAY_DATABASE_TYPE") config.password = ENV.fetch("PAYMENTGATEWAY_PASSWORD") config.server_name = ENV.fetch("PAYMENTGATEWAY_SERVER_NAME") config.username = ENV.fetch("PAYMENTGATEWAY_USERNAME") end
18. @MATTPOLITO