action pack request exception patching for the pre 2.3 era

request_exception_fix.rb

# Patch request to receive exceptions from body parsing (e.g. XML parsing)
ActionController::AbstractRequest.class_eval do

  alias_method :parse_formatted_request_parameters_unsafely, :parse_formatted_request_parameters

  def parse_formatted_request_parameters
    begin
      parse_formatted_request_parameters_unsafely #super
    rescue Exception => e # YAML, XML or Ruby code block errors
      self.env['EXCEPTION'] = e # there will be a before filter to check for this and re-raise
      { #"body" => raw_post,
        "content_type" => content_type_with_parameters, "content_length" => content_length }
    end
  end

end