ruby on rails - How to DRY scope methods used in two different classes? -

i using ruby on rails 3.2.2 , retrieve / scope associated objects "specifying" / "filtering on" attribute value on associated objects. is, @ time using following code:

class article < activerecord::base   def self.search_by_title(search)     where('articles.title ?', "%#{search}%")   end end  class articleassociation < activerecord::base   def self.search_by_article_title(search)     joins(:article).where('articles.title ?', "%#{search}%")   end end 

in above code where('articles.title ?', "%#{search}%") clause repeated twice , thought may improved dry principle: is possible use the article.search_by_title method directly in the articleassociation.search_by_article_title method?

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typical use cases are:

• articleassociation.search_by_article_title("sample string")
• article.search_by_title("sample string")

unless change code structure completely, no.

you hacking lambdas, more code code you're drying. there such thing refactoring, , such thing bad refactoring. unless piece of very complex or long code used in 2 or more places, can worry refactoring. code conventions important, tiny one-method-call things waste , make code more cryptic.

though, know it's annoying when people don't answer question, here:

class article < activerecord::base   search_by_title=lambda {|obj, search| obj.where('articles.title ?', "%#{search}%")}   def self.search_by_title(search)     search_by_title.call(self, search)   end end  class articleassociation < activerecord::base   def self.search_by_article_title(search)     article::search_by_title.call(joins(:article),search)   end end 

that makes lambda constant performs where call on specified object. both methods wrap lambda.

note: although may considered more elegant, decrease performance lot, lambdas, closures, , call expensive in dynamic language ruby. don't think that's issue you.