ApplicationController#handler_exception

gistfile1.rb

class ApplicationController < ActionController::Base
  helper :all # include all helpers, all the time
  # ...
  rescue_from Exception, :with => :handler_exception
  # ...

  def handler_exception(exception)
    if request.xhr? then
      message = "Error: #{exception.class.to_s}"
      message += " in #{request.parameters['controller'].camelize}Controller" if request.parameters['controller']
      message += "##{request.parameters['action']}" if request.parameters['action']
      message += "\n#{exception.clean_message}"
      message += "\n\nFull Trace:\n#{exception.clean_backtrace.join("\n")}"
      message += "\n\nRequest:\n#{params.inspect.gsub(',', ",\n")}"
      # log the error
      logger.fatal "#{message}"
      message = "ajaxError, check the server logs for details" unless local_request?
      respond_to do |wants|
        wants.js { render :text => message, :status => :internal_server_error  }
      end
    else
      # not an ajax request, use the default handling; 
      # actionpack-2.2.2/lib/action_controller/rescue.rb
      rescue_action_without_handler(exception) 
    end
    return # don't risk DoubleRenderError
  end
end