model missing required attr_accessor for 'photo_file_name' when uploading with paperclip and S3 on heroku

Setting up paperclip with S3 in my linux dev environment was a snap -- everything works out of the box. However, I can't get it to work on Heroku.

When I try to do an upload, the log shows:

Processing ItemsController#create (for 72.177.97.9 at 2010-08-26 16:35:14) [POST]  
  Parameters: {"commit"=>"Create", "authenticity_token"=>"0Hy3qvQBHE1gvFVaq32HMy2ZIopelV0BHbrSeHkO1Qw=", "item"=>{"photo"=>#<File:/home/slugs/270862_4aa601b_4b6f/mnt/tmp/RackMultipart20100826-6286-1256pvc-0>, "price"=>"342", "name"=>"a new item", "description"=>"a new item", "sold"=>"0"}}

Paperclip::PaperclipError (Item model missing required attr_accessor for 'photo_file_name'):

I found one blog post that referenced this error, and it said to add this to my model:

attr_accessor :phot开发者_开发百科o_file_name
attr_accessor :photo_content_type
attr_accessor :photo_file_size
attr_accessor :photo_updated_at

That does indeed make the model missing required attr_accessor for 'photo_file_name' error go away, but it still doesn't work. See my other question for details. As I have figured out that with the attr_accessor lines added to my model the uploads fail even on my dev system, I suspect that is not the right answer.

Found the problem: needed to update the database.

heroku run rake:db:migrate

heroku restart

I had done what I thought would have accomplished the same thing already:

heroku rake db:schema:load

but perhaps that doesn't work or something went wrong in the process.

Error like this occurs if you create wrong column type in migration. When you define new table migration for paperclip, you need to specify t.attachment :name insted of t.string :name. Or add_attachment :table, :name when you add new paperclip column in existed table. And now you don't need to add these attributes in attr_accessor in model.

Well, this message seems to be because the columns it's missing. Try create a migration creating the columns:

class AddPhotoToEvent < ActiveRecord::Migration
  def change
    add_column :events, :photo_file_name,    :string
    add_column :events, :photo_content_type, :string
    add_column :events, :photo_file_size,    :integer
    add_column :events, :photo_updated_at,   :datetime
  end

end

This work for me, here i have a table events with photo