In Rails, `ActionDispatch::Http::UploadedFile` has an accessor to access a `Tempfile` object. However, `Rack::Test::UploadedFile` does not provide that, but provinding the `#path` method instead. To be able to support both, we have to check for existance for `#tempfile` method, then fallback to `#path` method. Fixes #807
Needs work for S3 Attachments.
The new default :path and :include include the name of the model and also nests the model ID under a series of subdirectories, improving filesystem access speed when more than 1024 models have saved attachments. The easiest way to upgrade is to add an explicit :url and :path to your has_attached_file calls: has_attached_file :avatar, :path => ":rails_root/public/system/:attachment/:id/:style/:filename", :url => "/system/:attachment/:id/:style/:filename"
…ns that could be written include generating thumbnails on the fly for different thumbnail sizes, or delaying the thumbnail generation until it is first called.