Easy file attachment management for Sequel
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Paperclip is intended as an easy file attachment library for Sequel. It was heavily inspired by Paperclip for Activerecord. The intent behind it was to keep setup as easy as possible and to treat files as much like other attributes as possible. This means they aren't saved to their final locations on disk, nor are they deleted if set to nil, until #save is called. It has support for interpolations and postprocessors, including standart ones like a thumbnail generator by default.


Simply install it as any other gem:

gem install sequel_paperclip

Or when using bundler, add it got your Gemfile:

gem sequel_paperclip

Some postprocessors depend on external libraries or programs. Please see the processors sections for details.

Quick Start

In your model:

class User < Sequel::Model
  plugin :paperclip

  attachment :photo,
    :url => ":host:/:model:/:id:_:basename:_:style:.:format:",
    :path => ":path:/:model:/:id:_:basename:_:style:.:format:",
    :styles => {
      :small => { :geometry => "60x60#", :format => :jpg },
      :medium => { :geometry => "250x200>", :format => :jpg },
      :huge => { :geometry => "600x500>", :format => :jpg },
    :processors => [
        :type => :image,
        :convert_arguments => %w(-auto-orient -quality 75 -strip), # optional

In your migrations:

class AddPhotoToUser < Sequel::Migration
  def up
    alter_table :users do
      add_column :photo_basename, String
      add_column :avatar_file_size, Integer # optional

  def down
    alter_table :users do
      drop_column :photo_file_name
      drop_column :avatar_file_size

In your edit and new views:

<% form_for @user, :html => { :multipart => true } do |form| %>
  <%= form.file_field :photo %>
<% end %>

In your controller:

def create
  # nothing need's to be changed

def update
  # nothing need's to be changed

def destroy
  # nothing need's to be changed

In your show view:

<%= image_tag @user.photo_url(:small) %>
<%= image_tag @user.photo_url(:medium) %>
<%= image_tag @user.photo_url(:huge) %>


To support flexible urls and paths Paperclip supports variable interploations. Strings to be interpolated look like :xxx:. The following predefined interpolations exist:

id: record id
model: underscored, pluralized class name
host: "/system"
path: Rails public system folder
style: style (user.photo_url(:thumb) -> :thumb)
format: format defined for the passed style
filename: filename
filesize: only available if a database column photo_file_size exists
basename: basename of the filename
extname: extname of the filename
rails_root: Rails.root
rails_ev: Rails.env

To add your own interploation, put the following code in some initializer. If using rails a good location is initializers/paperclip.rb:

Sequel::Plugins::Paperclip::Interpolations.set(:host) do |attachment, model, style|
  Rails.env.production? ? "http://some.fancy.mirror.com" : "/system"

This would add/ replace the :host: interpolation.


Processors are run before the attachment is saved. Multiple processors can be specified, and they will be invoked in the order they are defined in the :processors array.

The following processors are included by default:


Adds the ability to generate thumbnails. Requires imagemagick to installed and the convert and identify commands being in the path and executable. Expects a geometry definition for each defined style. If a format is defined for a style, the image is converted to that format.


This processor is only used internally and should never be used.


Attachments are stored as files in the file system. To specify the location, please have a look at the example above and interpolations.


  • Source documentation (rdoc)

  • Tests


If you'd like to contribute a feature or bugfix: Thanks! To make sure your fix/feature has a high chance of being included, please read the following guidelines:

  1. Fork the project.

  2. Make your feature addition or bug fix.

  3. Add tests for it. This is important so we don’t break anything in a future version unintentionally.

  4. Commit, do not mess with rakefile, version, or history. (if you want to have your own version, that is fine but bump version in a commit by itself I can ignore when I pull)

  5. Send me a pull request. Bonus points for topic branches.