Rails两种模型之间的关系

Question

有没有一种方法可以确定Rails在两个模型之间动态创建的关系方法？

例如：

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 

看着Rails的API，但没有在我的尖叫，它可以做到这一点。

从本质上讲，这些方法的逆：http://api.rubyonrails.org/classes/ActiveRecord/Reflection/ClassMethods.html#method-i-reflect_on_association

Answer 1

您正在寻找这样的事情？

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]