Rails 3 - Paperclip: uninitialized constant ActionDispatch::Request::UploadedFile - ruby-on-rails

Question

I have a confusing error:
I run Rails 3.0.0 on Ruby 1.9.2 with Paperclip 2.3.5.
When I upload a file I get a 500 error.
NameError (uninitialized constant ActionDispatch::Request::UploadedFile):
config/initializers/fix_params.rb:13:in `normalize_parameters'
config/initializers/fix_params.rb:19:in `block in normalize_parameters'
config/initializers/fix_params.rb:19:in `each'
config/initializers/fix_params.rb:19:in `normalize_parameters'
config/initializers/fix_params.rb:19:in `block in normalize_parameters'
config/initializers/fix_params.rb:19:in `each'
config/initializers/fix_params.rb:19:in `normalize_parameters'
Rendered /Users/vjmayr/.rvm/gems/ruby-1.9.2-p0/gems/actionpack-3.0.0/lib/action_dispatch/middleware/templates/rescues/diagnostics.erb within rescues/layout (10.2ms)
I have seen similar things happen with Rails 3.0.2 and .3 but I have no idea why it happens here. Con anyone help me with finding the problem?
Thanks! Valentin
ADDED config/initializers/fix_params.rb:
module ActionController
class Request
private
# Convert nested Hashs to HashWithIndifferentAccess and replace
# file upload hashs with UploadedFile objects
def normalize_parameters(value)
case value
when Hash
if value.has_key?(:tempfile)
upload = value[:tempfile]
upload.extend(UploadedFile)
upload.original_path = value[:filename]
upload.content_type = value[:type]
upload
else
h = {}
value.each { |k, v| h[k] = normalize_parameters(v) }
h.with_indifferent_access
end
when Array
value.map { |e| normalize_parameters(e) }
else
value.force_encoding(Encoding::UTF_8) if value.respond_to?(:force_encoding)
value
end
end
end
end

Answer 1

tadman (Thanks!) pointed me towards the right solution:
All I had to do was change the value from tempfile to to_tempfile. This prabably won't happen to too many people, but I thought I'd mention as there has been a similar discussion around that due to a recent change in stable rails 3.0.3 by tenderlove, which is philisophically absolutely correct - but threw off some people...
So here is the changed fragment of fix_params.rb
...
if value.has_key?(:to_tempfile)
upload = value[:to_tempfile]
...
Cheers,
Val