Paperclip: undefined method `to_file' for #<Paperclip::Attachment:0000> (NoMethodError)

to_file has been removed Show archive.org snapshot in Paperclip 3.0.1.

Instead of using File to access Paperclip storage objects (like this: File.read(file.to_file.path)) you can use

CopyPaperclip.io_adapters.for(file).read