silence ActionController::UnknownHttpMethod exceptions

ignore_unknown_http_method.rb

# Avoid annoying ActionController::UnknownHttpMethod exceptions like:
#
#   ActionController::UnknownHttpMethod) "CONNECT, accepted HTTP methods are get, head, put, post, delete, and options"
#
# Install this file in app/metal and these requests will receive a 405
# "Method Not Allowed" status and will be logged under `info'.
class IgnoreUnknownHttpMethod
  def self.call(env)
    [
     if ActionController::Request::HTTP_METHODS.include?(env["REQUEST_METHOD"].downcase)
       404 # Not Found
     else
       Rails.logger.info("Ignoring unknown HTTP method; #{env.inspect}")
       
       405 # Method Not Allowed
     end, {"Content-Type" => "text/plain"}, []]
  end
end

It looks like you can modify Rails' exception to http status code mapping (at least in Rails 3.2) to do this:

 ActionDispatch::ExceptionWrapper.rescue_responses.merge!(
      'ActionController::UnknownHttpMethod' => :method_not_allowed)

It looks like this entry is in the map by default in Rails 4 so things should work out of the box there.