view
<%= form_tag({:action=>"upload"}, {:multipart => true} ) do %>
<%= file_field :upload, :datafile%>
<%= submit_tag "Upload" %>
<% end %>
ソース
<form accept-charset="UTF-8" action="/upload/upload" enctype="multipart/form-data" method="post">
<input id="upload_datafile" name="upload[datafile]" type="file" />
<input name="commit" type="submit" value="Upload" />
</form>
コントローラ
def upload
data=params[:upload]
File.open('./tmp/files/'+ data[:datafile].original_filename, 'wb') do |of|
of.write(data[:datafile].read)
end
redirect_to upload_index_path
end