Is it possible to extend accessor methods to include validation routines?

Question

How can one include validation routines to attr_write and attr_accessor?

Answer 1

Yes, you can 'Monkey Patch' the attr_* methods and modify it's behavior, but that's not a good idea. ( google 'monkey patching in ruby' )

Instead, it's good to write custom getter and setters to serve your purpose

Here's an example
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class Person < ActiveRecord::Base

# don't use attr_accessible here as it interferes/duplicates the methods below

# setter
def shirt=(value)
write_attribute(:shirt_fee_in_cents, value)
end

# getter
def shirt
if self[:shirt].present?
return self[:shirt]
end
AverageHuman.default_shirt
end
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Example taken from
https://richardcooke.info/how-to-make-a-custom-getter-setter-for-activerecord-ruby-on-rails-attributesproperties/