Install this plugin alongside paperclip.

It adds two small things:

• Automatically declares the fields for you, so you can just add

   has_attached_file :photo
  

  to your model, and then run the migration generator. All options are automatically passed on to paperclip's has_attached_file.

• Declares an input field

   <def tag="input" for="Paperclip::Attachment">
     <%= file_field_tag param_name_for_this, attributes %>
   </def>
  

  (to get this, you need <include src="paperclip" plugin="paperclip_with_hobo"/> in application.dryml)

Paperclip's official repository (https://github.com/thoughtbot/paperclip.git) has a bug (at the time of writing) that makes paperclip with hobo crash (see http://groups.google.com/group/hobousers/browse_thread/thread/752e154ff9725486).

But we can use a fork which is nicely patched. Add this to your Gemfile:

gem 'paperclip', :git => "git://github.com/jeanmartin/paperclip.git", :branch => "master"

Update your bundle:

bundle

Install paperclip_with_hobo:

rails plugin install git://github.com/tablatom/paperclip_with_hobo.git

Include the paperclip_with-hobo taglib in your application.dryml

<include src="paperclip" plugin="paperclip_with_hobo"/>

Add paperclip to one of your models:

has_attached_file :photo

Your default form for the model will now include the four attributes added by has_attached_file. To actually allow uploading, you will need to manually add the attachment field (photo in the above example) to your form, and don't forget to add the multipart attribute:

<extend tag="form" for="MyModel">
  <old-form merge multipart>
    <field-list: fields="photo, other-fields, ..."/>
  </old-form>
</extend>

The name of the plugin is important. It doesn't have to be paperclip_with_hobo but it will only work if this plugin loads after paperclip itself. Calling it paperclip_something is a good way to ensure that.