License: MIT

Language: Ruby


Dragonfly is a Rack framework for on-the-fly image handling.

Ideal for using with Ruby on Rails (2.3 and 3), Sinatra and all that gubbins.

However, Dragonfly is NOT JUST FOR RAILS, and NOT JUST FOR IMAGES!!

IMPORTANT: if you're running a version between 0.7.0 and 0.9.12, please update to at least 0.9.14 for a security update details here

For the lazy Rails user...


gem 'rack-cache', :require => 'rack/cache'
gem 'dragonfly', '~>0.9.15'

Initializer (e.g. config/initializers/dragonfly.rb):

require 'dragonfly/rails/images'


add_column :albums, :cover_image_uid,  :string
add_column :albums, :cover_image_name, :string  # Optional - only if you want urls
                                                # to end with the original filename


class Album < ActiveRecord::Base
  image_accessor :cover_image            # 'image_accessor' is provided by Dragonfly
                                         # this defines a reader/writer for cover_image
  # ...

View (for uploading via a file field):

<% form_for @album, :html => {:multipart => true} do |f| %>
  <%= f.file_field :cover_image %>
<% end %>


You can avoid having to re-upload when validations fail with

<%= f.hidden_field :retained_cover_image %>

remove the attachment with

<%= f.check_box :remove_cover_image %>

assign from some other url with

<%= f.text_field :cover_image_url %>

and display a thumbnail (on the upload form) with

<%= image_tag @album.cover_image.thumb('100x100').url if @album.cover_image_uid %>

View (to display):

<%= image_tag @album.cover_image.url %>
<%= image_tag @album.cover_image.thumb('400x200#').url %>
<%= image_tag @album.cover_image.jpg.url %>
<%= image_tag @album.cover_image.process(:greyscale).encode(:tiff).url %>

The above relies on imagemagick being installed. Dragonfly doesn't depend on it per se, but the default configuration 'dragonfly/rails/images' uses it. For alternative configurations, see below.

If using Capistrano with the above, you probably will want to keep the cache between deploys, so in deploy.rb:

namespace :dragonfly do
  desc "Symlink the Rack::Cache files"
  task :symlink, :roles => [:app] do
    run "mkdir -p #{shared_path}/tmp/dragonfly && ln -nfs #{shared_path}/tmp/dragonfly #{release_path}/tmp/dragonfly"
after 'deploy:update_code', 'dragonfly:symlink'

Sinatra, CouchDB, Mongo, Rack, S3, custom storage, processing, and more...

Dragonfly is not just for Rails - it's primarily a Rack app, so you can use it as a standalone app, or with Sinatra, Merb, etc.

It's highly customizable, and works with any data type (not just images).

For more info, consult the DOCUMENTATION


For third-party add-ons, see the Add-ons wiki


Please use the github issue tracker if you have any issues.


Google group dragonfly-users



Copyright (c) 2009-2010 Mark Evans. See LICENSE for details.

Project Statistics

Sourcerank 3
Repository Size 4.27 MB
Stars 0
Forks 0
Watchers 1
Open issues 0
Dependencies 22
Contributors 34
Tags 0
Last updated
Last pushed

Top Contributors See all

Henry Phan Philip Arndt Aidan Feldman Frederick Cheung Oliver Legg Kennon Ballou Matt Rohrer Malcolm Locke Michael Rykov Cyril Mougel Jon Rowe Andre Fonseca Federico Gonzalez Jeremy Seitz Jordan Elver João Maia Kazuaki Takase sidane Nicholas Henry Sam Rawlins

Something wrong with this page? Make a suggestion

Login to resync this repository