With Rails Paperclip gem, how to temporarily save the uploaded file if the model is invalid

Question

I am using the paperclip gem to attach files to models. When you upload a file using Paperclip, the file is saved ONLY when the model is saved. Thus, if the model is invalid, the uploaded file is not saved. Is there a way to temporarily save the uploaded file, so that the user doesn't have to upload the same file if the model is invalid?

Answer 1

Define a before_save method that checks if the object is valid, if not save the file to disk, give it a unique name (create some hash)

Put that in the form you send back in a hidden field

Delete the Upload field in the form

Now in the else branch of the before_save method check if there was a hidden_field previous_upload or however you name it If there is load the picture and assign it to the paperclip attribute, it can figure out the rest

attr_accessor :previous_upload

def before_save
  if valid?
    if previous_upload
      paperclip_file = #Load paperclip_file from /tmp
    else
      previous_upload = nil
    end
  else
    previous_upload = "Some unique key for each upload like ip and time or such"
    # Save paperclip_file with name previous_upload to /tmp
  end
end