= CarrierWave Backgrounder

I like CarrierWave. That being said, I don't like tying up app instances waiting for images to process and upload to S3. Depending on the size of the file, this could take a while sometimes timing out Heroku. This gem addresses that. After the file has been uploaded and CarrierWave caches the base file, it halts the process and queues a job.

== Installation

These instructions assume you have previously set up {CarrierWave}[https://github.com/jnicklas/carrierwave] and {DelayedJob}[https://github.com/collectiveidea/delayed_job]

In Rails, add the following your Gemfile:
    
    gem 'carrierwave_backgrounder'
    
== Getting Started

Add a column to the model you wan to background which will store the temp file location:
    
    add_column :users, :avatar_tmp, :string

In your CarrierWave uploader file:
    
    class AvatarUploader < CarrierWave::Uploader::Base
      include ::CarrierWave::Backgrounder::DelayStorage
      
      #ect...
    end
    
In your model:
    
    mount_uploader :avatar, AvatarUploader
    store_in_background :avatar
    
Currently ActiveRecord is the default orm and I have not tested this with others but it should work by adding the following to your carrierwave initializer:

    DataMapper::Model.send(:include, ::CarrierWave::Backgrounder::ORM)
    # or
    Mongoid::Document::ClassMethods.send(:include, ::CarrierWave::Backgrounder::ORM)
    # or
    Sequel::Model.send(:extend, ::CarrierWave::Backgrounder::ORM)

== Word Of Caution

Temp files are stored by default in the tmp directory. They are not guaranteed to be available when your workers process them! For instance, on Heroku, they get blown away on every deploy. If image upload is the main function of your app, I would store the tmp files in a non-volatile directory if you have the option.

== TODO

Transfer tests from rails app.

== License

Copyright (c) 2011 Larry Sprock

Permission is hereby granted, free of charge, to any person obtaining
a copy of this software and associated documentation files (the
"Software"), to deal in the Software without restriction, including
without limitation the rights to use, copy, modify, merge, publish,
distribute, sublicense, and/or sell copies of the Software, and to
permit persons to whom the Software is furnished to do so, subject to
the following conditions:

The above copyright notice and this permission notice shall be
included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.