Nifty Attachments

Nifty attachments allow you to attach files/images/documents to Active Record models with ease. Just define which attachments you wish to add and you can easily upload them to your database.

• All attachment data is stored in your database
• Attachments are accessed at /attachment/{token}/{filename}. Middleware is provided to provide endpoint.

In order to get started, add the gem to your Gemfile:

gem 'nifty-attachments'

Once included, add the database table which will store your attachments.

$ rails generate nifty:attachments:migration
$ rake db:migrate

You can then define the attachments which you wish to use on any of your models as such:

class Person < ActiveRecord::Base
  attachment :cover_photo
  attachment :profile_picture
end

You can access any of your attachments easily through the methods as shown below.

# Accessing attachments
person = Person.find(person.id)
person.cover_photo            #=> Nifty::Attachments::Attachment
person.cover_photo.path       #=> "/attachment/145d17ed-d5e3-4b55-8c89-ecad9521ad73/snom-mm2.jpg"
person.cover_photo.file_name  #=> "snom-mm2.jpg"
person.cover_photo.digest     #=> "5d41402abc4b2a76b9719d911017c592"

# Pre-loading attachments will only load meta data, the actual content will
# not be loaded.
people = Person.includes(:profile_picture)

You can upload attachments straight from forms into your models by using the _file accessor which is provided.

<% form_for @person, :html => {:multipart => true} do |f| %>
  <%= f.file_field :profile_picture_file %>
  <%= f.file_field :cover_photo_file %>
  <%= f.submit "Upload Attachments" %>
<% end %>

If additional processing is required for an uploaded file, this can be acheived by passing a block to the attachment method.

attachment :image do |attachment|
  # Do your additional processing on this attachment
  # This might include making thumbnails of an image etc...
end

By default, all processing will happen syncronously which may not be desirable if the processing will take time. To background the processing automatically, you can request the assistance of a worker. You need to use your own worker system to do this, an example is provided below.

# Configure how jobs should be queued
Nifty::Attachments::Processor.background do |attachment|
  ProcessAttachmentJob.queue(:attachment_id => attachment.id)
end

# Define a job (if you don't preload your app, be sure to get the parent initialized before trying to run any processing
# otherwise the processors won't have registered),
class ProcessAttachmentJob < Jobster::Job
  def perform
    if attachment = Nifty::Attachments::Attachment.includes(:parent).find(params['attachment_id'])
      attachment.processor.process
    end
  end
end

Once you have registered a block for queueing (using background), all attachments for the application will be processed in the background.

There are a few extra things which need adding to this library:

• A test suite
• Validations