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

I found the workaround to pickup styles on create. The key is to implement before_post_process and after_save hooks.

class Image < ActiveRecord::Base

  DEFAULT_STYLES = {
    medium: "300x300>", thumb: "100x100>"
  }

  has_attached_file :file, styles: ->(file){ file.instance.styles }


  validates_attachment_content_type :file, :content_type => /\Aimage\/.*\Z/

  # Workaround to pickup styles from imageable model
  # paperclip starts processing before all attributes are in the model
  # so we start processing after saving

  before_post_process ->{
    !@file_reprocessed.nil?
  }

  after_save ->{
    if !@file_reprocessed && (file_updated_at_changed? || imageable_type_changed?)
      @file_reprocessed = true
      file.reprocess!
    end
  }


  belongs_to :imageable, polymorphic: true

  def styles
    if imageable_class.respond_to?(:image_styles)
      imageable_class.image_styles
    end || DEFAULT_STYLES
  end

  def imageable_class
    imageable_type.constantize if imageable_type.present?
  end


end

So you have to define image_styles class method in imageable_class In my case it was

class Property < ActiveRecord::Base

  def self.image_styles
    {
      large: "570x380#",
      thumb: "50x70#",
      medium: "300x200#"
    }
  end

end