module<\/span> BlahPlugin<\/span><\/div> VERSION<\/span> =<\/span> '1.0.0'<\/span><\/div> <\/div>
class<\/span> <<<\/span> self<\/span><\/div> # add plugin to AR only if it hasn't been included before, <\/span><\/div> # which may cause stack-level-too-deep errors if you're aliasing methods<\/span><\/div> #<\/span><\/div> def<\/span> enable_activerecord<\/span><\/div> return<\/span> if<\/span> ActiveRecord<\/span>::<\/span>Base<\/span>.<\/span>respond_to?<\/span> :acts_as_blah<\/span><\/div> ActiveRecord<\/span>::<\/span>Base<\/span>.<\/span>extend<\/span> BlahPlugin<\/span>::<\/span>Macro<\/span><\/div> end<\/span><\/div> end<\/span><\/div> <\/div>
module<\/span> Macro<\/span><\/div> # his class level method injects the rest of the plugin behaviour in the affected class.<\/span><\/div> # use like this:<\/span><\/div> # class Post < ActiveRecord::Base<\/span><\/div> # acts_as_blah<\/span><\/div> # end<\/span><\/div> #<\/span><\/div> def<\/span> acts_as_blah<\/span>(<\/span>opts<\/span> =<\/span> {<\/span>:some_option<\/span> =><\/span> true<\/span>}<\/span><\/div> # don't include modules twice<\/span><\/div> return<\/span> if<\/span> self<\/span>.<\/span>included_modules<\/span>.<\/span>include?<\/span>(<\/span>BlahPlugin<\/span>::<\/span>InstanceMethods<\/span>)<\/span><\/div> # include class and instanc methods<\/span><\/div> extend<\/span> BlahPlugin<\/span>::<\/span>ClassMethods<\/span><\/div> include<\/span> BlahPlugin<\/span>::<\/span>InstanceMethods<\/span><\/div> # do something else, like initializing options<\/span><\/div> end<\/span><\/div> end<\/span> <\/div> <\/div>
module<\/span> ClassMethods<\/span><\/div> # class methods injected by the plugin, alias_method chaining, macro calls (has_many, after_save, validates),etc.<\/span><\/div> end<\/span><\/div> <\/div>
module<\/span> InstanceMethods<\/span><\/div> # instance methods injected by the plugin. callbacks, etc.<\/span><\/div> end<\/span><\/div> <\/div>
end<\/span><\/div> <\/div>
require<\/span> 'rubygems'<\/span><\/div>require<\/span> 'active_record'<\/span><\/div># enable the thing!<\/span><\/div>BlahPlugin<\/span>.<\/span>enable_activerecord<\/span><\/div> <\/div><\/pre><\/div>\n \n <\/div>\n\n