Question

I have a parent class in rails that inherits from ActiveRecord::Base. I’m trying to implement a freetext search, plus other queries, in that class such that all classes that inherit from it can use it with their own fields, which change based on the model:

#
# in base class
#
class GenericBase < ActiveRecord::Base

  named_scope :freetext, lambda { |query|
    if query.present?
      { :conditions => [ self.freetext_fields.join(' LIKE ? or '), 
                         ( ["%#{query}%"]*self.freetext_fields.size ) ].flatten }
    else
      {}
    end
  }

end

#
# in inheriting class
#
class Person < GenericBase
  set_freetext_fields %w(firstname lastname username email)    
end

# or 
class Address < GenericBase
  set_freetext_fields %w(street city)    
end

#
# in controller
#
def search
  @people = Person.freetext(params[:query])
end

In the example above, how do I implement the set_freetext_fields setter to be easily used in all models that inherit from GenericBase? This should be something very similar to set_table_name available in Rails.

I want to implement it in the parent or a mixin module such that the API for inheriting classes will be as clean as possible.

Answer 1

You can implement something like this:

module A
    def set_freetext_fields=(*args)
     @a = args
    end

    def some_meth
     @a 
    end
end

class C
 extend A   

 C.set_freetext_fields = %w(firstname lastname username email)
end

puts C.set_freetext_fields

Where C is GenericBase class