CODEWITHSUNDEEP
ruby-on-railsactiverecordrails-activerecord
Fellow Stranger
Fellow Stranger

Reputation: 34073

Use method argument as placeholder for chained relation

class Category
  has_many :posts
  has_many :images
end

Is it possible to chain a relation like below without explicitly write the plural form of the associated model? And if possible, of what type should the argument be?

def get_all(children_of_certain_model)
  self.children_of_certain_model.size
end
# one_category.get_all(:posts)

I know that for the case above I could simple call one_category.posts directly, but I'm just curious in general if it at all is possible to abstract the chained relation.

Upvotes: 1

Views: 62

Answers (1)

potashin
potashin

Reputation: 44601

As @Sergio Tulentsev suggested, you can use public_send to call only public methods with symbol syntax. You can also use just send, but also set a list of permitted for output associations (the behaviour is not equivalent, of course):

class Category
  has_many :posts
  has_many :images

  has_many :emails
end

def get_all(association)
  self.send(association).size if association.in?([:posts, :images])
end

one_category.get_all(:emails) #=> nil

Upvotes: 1

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