Integrate kt-paperclip into Mongoid. (Kt-paperclip is a maintained fork of the original Paperclip that is now deprecated)

This is actually easier and faster to set up than when using Paperclip and the ActiveRecord ORM.

Setting it up


gem "mongoid-paperclip"

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

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 has_mongoid_attached_file will automatically define the necessary :avatar fields for you.

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

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  => '',
    :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 do |picture|
  <%= picture.attachment.url %>

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, ...

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

Optional fingerprinting

Paperclip will skip calculating the fingerprint of a file when the {file}_fingerprint field is missing from the model. This can be desirable if attaching large files to a model. To disable adding the fingerprint field pass the disable_fingerprint option as in this example:

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

  has_mongoid_attached_file :usage_report, disable_fingerprint: true


If you want to help develop this plugin, clone the repo and bundle to get all dependencies.

Then to run the tests:


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 kt-paperclip I suggest checking our their official documentation and website.


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