两种模型之间的Rails关系

Question

Is there a way to determine the relationship method Rails creates between two models dynamically?

For example:

unknown_method_i_wish_existed(class_name_1, class_name_2)
  # awesome logic
  # returns the relationship method name going from class_name_1 to class_name_2
end

Looked over Rails API but nothing screamed at me that it could do this.

Essentially the inverse of these methods: http://api.rubyonrails.org/classes/ActiveRecord/Reflection/ClassMethods.html#method-i-reflect_on_association

Answer 1

Are you looking for something like this?

def reflection_names_between(from, to)
  from.reflections.select { |name, refl| refl.klass == to }.values.map(&:macro)
end

# For a Car that has one :owner and many :passengers
reflection_names_between(Car, User) # => [:belongs_to, :has_many]