class Picture < ActiveRecord::Base validates_format_of :content_type, :with => /^image/, :message => "--- you can only upload pictures" def uploaded_picture=(picture_field) self.name = base_part_of(picture_field.original_filename) self.content_type = picture_field.content_type.chomp self.data = picture_field.read end def base_part_of(file_name) File.basename(file_name).gsub(/[^\w._-]/, '') end end