Ruby on Rails - Can I modify the value of an attribute before it is called?

Question

Let's say I have this model named Product with a field named brand. Suppose the values of brand are stored in the format *this_is_a_brand*. Can I define a method in the model (or anywhere else) that allows me to modify the value of brand before it is called. For example, if I call @product.brand, I want to get This is a Brand, instead of *this_is_a_brand*.

Answer 1

In your model you can override the method call brand.

def brand
#code to modify the value that is stored in brand
return modified_brand
end

This will allow it to be stored as this_is_a_brand. But, it will be returned as "this is a brand".

Answer 2

Rather than accessing @attributes directly, you should use read_attribute and write_attribute:

def brand
  b = read_attribute(:brand) 
  b && b.transform_in_some_way
end

def brand=(b)
  b && b.transform_in_some_way
  write_attribute(:brand, b)
end

Answer 3

I would recommend using the square bracket syntax ([] and []=) instead of read_attribute and write_attribute. The square bracket syntax is shorter and designed to wrap the protected read/write_attribute methods.

def brand
  original = self[:brand]
  transform(original)
end

def brand=(b)
  self[:brand] = reverse_transform(b)
end