Mongoid::Paperclip - Making Paperclip play nice with Mongoid ODM

As the title suggests: Mongoid::Paperclip makes it easy to hook up Paperclip with Mongoid.

This is actually easier and faster to set up than when using Paperclip and the ActiveRecord ORM. This example assumes you are using Ruby on Rails 3 and Bundler. However it doesn't require either.

Setting it up

Simply define the mongoid-paperclip gem inside your Gemfile. Additionally, you can define the aws-s3 gem if you want to upload your files to Amazon S3. You do not need to explicitly define the paperclip gem itself, since this is handled by mongoid-paperclip.

Rails.root/Gemfile - Just define the following:

gem "mongoid-paperclip", :require => "mongoid_paperclip"
gem "aws-s3",            :require => "aws/s3"

Next let's assume we have a User model and we want to allow our users to upload an avatar.

Rails.root/app/models/user.rb - include the Mongoid::Paperclip module and invoke the provided class method

class User
  include Mongoid::Document
  include Mongoid::Paperclip

  has_mongoid_attached_file :avatar
end

That's it

That's all you have to do. Users can now upload avatars. Unlike ActiveRecord, Mongoid doesn't use migrations, so we don't need to define the Paperclip columns in a separate file. Invoking the has_mongoid_attached_file method will automatically define the necessary :avatar fields for you in the background.

A more complex example

Just like Paperclip, Mongoid::Paperclip takes a second argument (hash of options) for the has_mongoid_attached_file method, so you can do more complex things such as in the following example.

class User
  include Mongoid::Document
  embeds_many :pictures
end

class Picture
  include Mongoid::Document
  include Mongoid::Paperclip

  embedded_in :user, :inverse_of => :pictures

  has_mongoid_attached_file :attachment,
    :path           => ':attachment/:id/:style.:extension',
    :storage        => :s3,
    :url            => ':s3_alias_url',
    :s3_host_alias  => 'something.cloudfront.net',
    :s3_credentials => File.join(Rails.root, 'config', 's3.yml'),
    :styles => {
      :original => ['1920x1680>', :jpg],
      :small    => ['100x100#',   :jpg],
      :medium   => ['250x250',    :jpg],
      :large    => ['500x500>',   :jpg]
    },
    :convert_options => { :all => '-background white -flatten +matte' }
end

@user.pictures.each do |picture|
  <%= picture.attachment.url %>
end

Note on embedded documents: if you plan to save or update the parent document, you MUST add cascade_callbacks: true to your embeds_XXX statement. Otherwise, your data will be updated but the paperclip functions will not run to copy/update your file.

In the above example:

    class User
    ...
    embeds_many :pictures, :cascade_callbacks => true
    accepts_nested_attributes_for :pictures, ...
    attr_accepted :pictures_attributes, ...
    ...
    end

    @user.update_attributes({ ... :pictures => [...] })

There you go

Quite a lot of people have been looking for a solution to use Paperclip with Mongoid so I hope this helps!

If you need more information on either Mongoid or Paperclip I suggest checking our their official documentation and website.

License

Mongoid::Paperclip is released under the MIT license. See LICENSE for more information.