Uploader

Uploader makes it easy to integrate multiple file uploads into your application using SWFUpload

Installation

Install the gem:

sudo gem install uploader

Installing uploader should also install mime-types and rack. If for some reason it does not then manually install it: sudo gem install mime-types sudo gem install rack

Add the gem to environment.rb

config.gem ‘uploader’

Install jQuery

uploader uses jQuery. You’ll need to include it in your application. Download it here: jquery.com/

Then include it in your layout:

  <%= javascript_include_tag 'jquery/jquery.js' %>

Another option is to use jRails ennerchi.com/projects/jrails

Create a model for uploads.

We recommend creating a model called upload.rb. acts_as_uploader accepts all valid options for paperclip via :has_attached_file => {}

  class Upload < ActiveRecord::Base

   acts_as_uploader  :enable_s3 => false,
                     :has_attached_file => {
                       :url     => "/system/:attachment/:id_partition/:style/:basename.:extension",
                       :path    => ":rails_root/public/system/:attachment/:id_partition/:style/:basename.:extension",
                       :styles  => { :icon => "30x30!",
                                     :thumb => "100>",
                                     :small => "150>",
                                     :medium => "300>",
                                     :large => "660>" },
                       :default_url => "/images/profile_default.jpg",
                       :storage => :s3,
                       :s3_credentials => AMAZON_S3_CREDENTIALS,
                       :bucket => "assets.example.com",
                       :s3_host_alias => "assets.example.com",
                       :convert_options => {
                          :all => '-quality 80'
                        }
                     },
                     :s3_path => ':id_partition/:style/:basename.:extension'

    # only allow images:
    # validates_attachment_content_type :file, :content_type => ['image/jpeg', 'image/pjpeg', 'image/jpg']

    # limit uploads to 10 MB
    # validates_attachment_size :local, :less_than => 10.megabytes

    # The following method is implemented in 'acts_as_uploader'.  This is the method destroy will check to see if
    # the user has permission to delete the object.  Add additional logic as needed or if the existing logic
    # looks fine then feel free to delete this comment and the can_edit? method.
    def can_edit?(check_user)
      return false if user.blank?
      check_user == self.user
    end

  end

Add multiple file uploads to one of your models

Your uploads will need a parent object to attach to. For example, a user might have many files:

  class User < ActiveRecord::Base
    has_many :uploads, :as => :uploadable, :order => 'created_at desc', :dependent => :destroy

    def can_upload?(check_user)
      self == check_user
    end
  end

or a photo album might have many photos

  class PhotoAlbum < ActiveRecord::Base
    has_many :photos, :as => :uploadable, :order => 'created_at desc', :dependent => :destroy

    def can_upload?(check_user)
      self.editors.include?(check_user)
    end
  end

Note that in both examples there is an implementation of ‘can_upload?’. This method must be included in any parent object and will control who has permission to upload files.

The application controller

Be sure you have turned on protect from forgery. This is required for uploader to get the appropriate tokens from your Rails application. It is also a good idea and is the default in new Rails applications.

  protect_from_forgery # See ActionController::RequestForgeryProtection for details

The uploads controller

You can modify the upload controller behavior by inheriting from the uploader controller. For example, you might want to require that users be logged in to upload a file. There are a number of methods in the uploads controller that contain default functionality that you may consider overriding.

Be sure to modify your routes file. Add the following line to ensure that your application uses the new uploads controller instead of directly using the one inside the gem:

  map.resources :uploads, :collection => { :swfupload => :post }

  class UploadsController < Uploader::UploadsController

    prepend_before_filter :login_required

    protected

    # The default 'get_upload_text' method throws an exception.  You must override this method in your controller.  It
    # is used by the swf upload call to generate the html to be returned to the client.
    # Here's an example:
    def get_upload_text(upload)
      render_to_string( :partial => 'uploads/upload_row', :object => upload, :locals => { :parent => @parent } )
    end

    # The existing method will handle most cases but you might choose a different message or a different redirect:
    def permission_denied
      message = t("uploader.permission_denied")
      respond_to do |format|
        format.html do
          flash[:notice] = message
          redirect_to get_redirect
        end
        format.js { render :text => message }
        format.json { render :json => { :success => false, :message => message } }
      end
    end

    # Simply attempts to redirect to the parent object.  You might want to build something more sophisticated that
    # redirect to different areas of you site depending on the type of object that was uploaded or on based on the parent.
    # source can be :destroy_success, :create_success, :create_failure, :permission_denied
    def get_redirect
      @parent
    end

    # The default action is to call 'can_upload?' on the parent object.  Be sure to implement 'can_upload?(check_user) on
    # your parent objects
    def has_permission_to_upload(user, upload_parent)
      upload_parent.can_upload?(user)
    end

    # By default the controller will use a model named 'Upload' to do a destroy.  If you want to use a different model
    # you'll need to override 'set_upload_for_destroy in your controller to find the object using a different object.
    # For example:
    def set_upload_for_destroy
      @upload = Photo.find(params[:id])
    end

  end

Configure your views.

You’ll need something like this in your layout so that uploader can add in the required css and javascript files.

<%= yield :head -%>

Then to add an upload form: <%= upload_form(parent_object) %> parent_object should be the object which owns the uploads. ie a user, photo_album, etc.

Rake Tasks

Add the rake tasks for uploader to your project. You will need to add the following to your applications’s Rakefile

  require 'uploader'
  require 'uploader/tasks'

Then run:

  rake uploader:sync

Last run:

  rake db:migrate

This will create an uploads table for you. If you selected a different name for your model you will need to modify the migration accordingly.

WARNING

The migration will drop any existing ‘uploads’ table you have in place

That will copy all the required javascript and asset files into your project

Amazon s3

If you’d like to store your uploads on Amazon’s S3 service there are a few extra steps involved. See the example file above to view the options in context.

Turn on s3

Set the enable_s3 option to true in acts_as_uploader

  :enable_s3 => true

Pass your s3 credentials into acts_as_uploader

  :has_attached_file => { :s3_credentials => File.join(RAILS_ROOT, 'config', 's3.yml') }

Setup your credentials

Create a file named s3.yml in your configuration directory and add the following lines:

  access_key_id: PUT YOUR KEY HERE
  secret_access_key: PUT YOUR SECRET ACCESS KEY HERE

Turn on the Daemon process

There are a number of timing issues that you will run into if you attempt to upload files directly to s3. To overcome that problem uploader includes a daemon process which will send the files to Amazon asynchronously. Note that the uploader will leave your local copy in place.

Add the daemons gem and plugin:

  sudo gem install daemons

Then inside your Rails project:

  script/plugin install git://github.com/dougal/daemon_generator.git
  script/generate daemon amazonaws

If you have already run rake uploader:sync it will have already copied a file called amazonaws.rb into lib/daemons. Running script/generate daemon amazonaws will create the other files required to support that process. You will get a prompt "overwrite lib/daemons/amazonaws.rb?". Answer ‘n’o as the file is already setup.

To start the daemon locally:

  RAILS_ENV=development lib/daemons/amazonaws_ctl start

There is also an app wide control script that you can add to capistrano:

  ./script/daemons [start|stop|restart]

Learn more about the custom daemon gem with Ryan Bates screencast:

  http://railscasts.com/episodes/129-custom-daemon

Use Rake to send files to s3

uploader includes a task capable of sending files to s3 but it makes an assumption that the model you are interacting with is named ‘Upload’.

  rake uploader:upload_to_s3

If you want to use a different model or several models just add a rake task to your project:

  desc 'Send all uploads to S3.  (Will only send uploads from a model named Upload)'
  task :upload_to_s3 do

    uploads = Upload.pending_s3_migration
    uploads.each do |upload|
      upload.remote = upload.local
      upload.save!
    end

    photos = Photo.pending_s3_migration
    photos.each do |photo|
      photo.remote = photo.local
      photo.save!
    end

  end

Setup Domains

If you use Amazon’s S3 service you can setup a cname to clean up your urls. Configure your s3 bucket as above:

  :bucket => "assets.example.com"
  :s3_host_alias => "assets.example.com"

Your assets will be available at assets.example.com.s3.amazon.com. You can then create a CNAME in your DNS entries to point "assets.example.com" to "assets.example.com.s3.amazon.com". Your assets will then appear to be be served from assets.example.com even though they are loaded from Amazon.

Other Stuff

If you’d like to add an ajax delete to your uploads page this code might come in handy.

Say you have chosen to display your upload in a table. Your code might look like the following. Note that there are a number of assumptions made in this code. Modify it to suite your needs.

  <tr id="<%= upload_row.dom_id %>" class="delete-container <%= cycle('odd', 'even') %>" <%=style-%> >
        <td><div class="file-icon"><%= image_tag upload_row.icon -%></div></td>
        <td><a href="<%=upload_row.file.url%>"><%= truncate(sanitize(upload_row.file_name), 100) %></a></td>
        <td><%= upload_row.created_at.to_s(:long) -%></td>
        <td>
                <% if parent.can_edit?(current_user) -%>
                        <% form_for(:upload, :url => upload_path(upload_row.id), :html => { :class => "delete-form", :method => :delete} ) do |f| -%>
                                <%= image_submit_tag '/images/icons/delete.png', {:id => 'submit-comment', :title => t('general.delete_file'), :class => 'submit-delete', :width => '12', :height => '12', :alt => t('general.delete_file') } %>
                        <% end -%>
                        <% if !style.empty? -%>
                        <script type="text/javascript" language="JavaScript">
                                jQuery("#<%= upload_row.dom_id %>").fadeIn("slow");
                        </script>
                        <% end -%>
                <% end -%>
        </td>
  </tr>

I put the following in my main upload view

  <% content_for :javascript do  -%>

    setup_submit_delete();

    function upload_completed_callback(data){
      jQuery('#upload-list').prepend(data);
      setup_submit_delete();
    }
  <% end -%>

The following jQuery code will do an ajax delete for you

  function setup_submit_delete(){
        jQuery(".submit-delete").click(function() {
                // if(!confirm("Are you sure?")){
                //  return false;
                // }
      jQuery(this).parents('.delete-container').fadeOut();
      var form = jQuery(this).parents('form');
      jQuery.post(form.attr('action') + '.json', form.serialize(),
        function(data){
          var json = eval('(' + data + ')');
          if(!json.success){
            jQuery.jGrowl.info(json.message);
          }
        });
      return false;
    });
  }

Testing

If you intend to develop code and wish to run the tests you may do so using rake test. However, note that you will need to install the gem first using rake install since the embedded test application will use the gem that is install and not the current code from the project. This is a limitation I attempted to overcome using a special initializer in rails_root/config/initializers/uploader.rb but I didn’t have any success getting it working.

Copyright © 2009 Justin Ball, released under the MIT license