Request: Support style-specific processing images

[Undistraction]

It would be great to handle processing_image_url in the same way that Paperclip allows you to use an interpolator for :default_url. The key feature is that this allows you to supply an image based on the syle which doesn't appear to be possible with processing_image_url which isn't supplied with any context.

Usecase: Throughout my application I use square thumbs, whereas the rest of the images are their native aspect ratios. With Delayed Paperclip's current implementation there is no way to supply a square image to the thumnails and a generic 4:3 image to the rest of places it is used.

[consti]

This might not be exactly what you are looking for, but I wanted to show style: :original whereever I requested the original file, even if it was still processing (and show all missing ones everywhere else, until processed).

I made this monkey patch:
(in initializers/delayed_paperclip.rb)

module DelayedPaperclip
  module UrlGenerator
    alias_method :old_delayed_default_url?, :delayed_default_url?
    def delayed_default_url?(style = nil)
      return false if style == :original
      old_delayed_default_url?(style)
    end
  end
end

[cgunther]

You can pass processing_image_url a string with values to be interpolated just like you would give Paperclip.

For example, I use a processing_image_url like so:

process_in_background :image, processing_image_url: '/images/processing/:attachment/:style.gif'

This means if I call model.image.url(:square), I'd get back a URL like /images/processing/images/square.gif.

If you need to pass processign_image_url a callable, then you are right that you have no context to know which style to return.