Rack File

The rack_file plugin enables uploaders to accept Rack uploaded file hashes for uploading.

plugin :rack_file

Usage

When a file is uploaded to your Rack application using the multipart/form-data parameter encoding, Rack converts the uploaded file to a hash.

file_hash #=>
# {
#   :name => "file",
#   :filename => "cats.png",
#   :type => "image/png",
#   :tempfile => #<Tempfile:/var/folders/3n/3asd/-Tmp-/RackMultipart201-1476-nfw2-0>,
#   :head => "Content-Disposition: form-data; ...",
# }

Since Shrine only accepts IO objects, you would normally need to fetch the :tempfile object and pass it directly. This plugin enables the attacher to accept the Rack uploaded file hash directly, which is convenient when doing mass attribute assignment.

user.avatar = file_hash
# or
attacher.assign(file_hash)

API

Internally the Rack uploaded file hash will be converted into an IO object using Shrine.rack_file, which you can also use directly:

# or YourUploader.rack_file(file_hash)
io = Shrine.rack_file(file_hash)
io.original_filename #=> "cats.png"
io.content_type      #=> "image/png"
io.size              #=> 58342

Note that this plugin is not needed in Rails applications, as Rails already wraps the Rack uploaded file hash into an ActionDispatch::Http::UploadedFile object.