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'Configurable' module for Ruby, similar to https://github.com/markevans/configurable
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| #!/usr/bin/env ruby | |
| # Makes a class globally configurable, e.g. in a Rails initializer. | |
| # Usage: | |
| # `class MyClass | |
| # include Configurable | |
| # create_config do | |
| # # url attribute has a default value, which is the return value of the block | |
| # url { 'http://www.example.com'} | |
| # # name attribute is allowed but has no default value | |
| # name | |
| # end | |
| # | |
| # def do_something | |
| # fetch(configuration.url + "?name=" + configuration.name) | |
| # end | |
| # end` | |
| # Then, in your app's startup: | |
| # `MyClass.configure do |c| | |
| # c.name = 'my_name' | |
| # end` | |
| # and now, in your application: | |
| # `MyClass.new.do_something` => `fetch('http://example.com?name=my_name')` | |
| module Configurable | |
| # Creates a configuration struct for a class based | |
| # on the contents of the `configure` block. | |
| class CFactory | |
| attr_accessor :attributes | |
| def initialize | |
| @attributes = {} | |
| end | |
| def method_missing(name, *args, &block) | |
| attributes[name] = {} | |
| attributes[name][:dv] = block.call() unless block.nil? | |
| end | |
| def build(name) | |
| attrs = attributes.keys.map(&:to_sym) | |
| dvs = Hash[attributes.select { |k, v| v[:dv] }.map { |k, v| [k, v[:dv]] }] | |
| Struct.new(name, *attrs) do | |
| define_method(:initialize) do |options = {}| | |
| members.each do |m| | |
| send "#{m}=", options.fetch(m,dvs[m]) | |
| end | |
| end | |
| end | |
| end | |
| end | |
| def self.included(base) | |
| base.extend(ClassMethods) | |
| base.instance_variable_set(:@config, {}) | |
| end | |
| def configuration | |
| # deep copy of configuration class | |
| @configuration ||= Marshal.load(Marshal.dump(self.class.instance_variable_get(:@default_config))) | |
| end | |
| module ClassMethods | |
| def configure | |
| yield @default_config | |
| end | |
| def create_config(&block) | |
| factory = CFactory.new | |
| factory.instance_eval(&block) | |
| conf = "#{self.name}Configuration" | |
| struct = factory.build(conf) | |
| const_set('Configuration', struct) | |
| instance_variable_set(:@default_config, struct.new) | |
| end | |
| end | |
| end | |
| class Test | |
| include Configurable | |
| create_config do | |
| url { 'http://www.example.com' } | |
| name | |
| end | |
| end | |
| #Test.configure do |c| | |
| # c.url = 'ackthppt' | |
| #end | |
| t = Test.new | |
| puts t.configuration | |
| Test.configure do |c| | |
| c.url = 'ackthppt' | |
| end | |
| t2 = Test.new | |
| puts t2.configuration | |
| puts "did we mess up?" | |
| puts t.configuration == t2.configuration |
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One difference between the referenced gem and this is that it creates a custom 'Configuration' class for your class, which can be instantiated normally if you need multiples, e.g.
Test::Configuration.new(url: 'https://www.example.com')