Paperclip :style depending on model (has_many polymorphic images)

Question

I have set up my models to use a polymorphic Image model. This is working fine, however I am wondering if it is possible to change the :styles setting for each model. Found some

Answer 1

After couple of hours of digging into source code of both, ActiveRecord and Paperclip, I think there's a solution involving a bit of monkey-patching hackery.

I haven't thoroughly tested it but seems to work for my humble needs.

Below is my config/initializers/activerecord_associations_patch.rb:

module ActiveRecord
  module Associations
    class HasManyAssociation

      def build_record(attributes)
        if options[:as] && owner
          # Unicorns
          reflection.build_association({}) do |record|
            set_owner_attributes(record)
            unless foreign_key_for?(record)
              record.public_send "#{options[:as]}=", owner
            end
            initialize_attributes(record)
            record.assign_attributes(attributes)
          end
        else
          # Classic Rails way
          reflection.build_association(attributes) do |record|
            initialize_attributes(record)
          end
        end
      end

    end
  end
end

Since reflection doesn't know our @owner, it first assigns the attributes which triggers call to record.#{instance}= (i.e. Image#file=), which in turn forwards it to #assign and performs post_processing hook, which in the end leads to calling styles Proc provided in has_attached_file without polymorphic imageable being set. huh…

I rewrote the method to build the record first and assign provided attributes later. Also, it accounts for record#new_record? in foreign_key_for? check.

In this way attributes are assigned once the record has been properly setup. At least i think so ;)

Cleaner solutions and constructive comments are most welcome :)