Responders, JSON, and PUT requests

When I use jQuery (1.4.2) to execute a PUT request

  $.ajax({
    url: urlc,
    type: 'PUT', // POST + _method='PUT' makes no difference
    dataType: 'json',
    data: data,

against a Rails (3.0.0.beta4) controller using respond_with

  def update
    @resource.update_attribute(...)
    respond_with(@resource)
  end

Then jQuery indicates an error even if Rails sends a success response.

Here's what's happening: ActionController::Responder#api_behavior
responds with head :ok. Which in turn writes a response body containing
a single space.

In the browser, jQuery, as requested, parses the response body, using
its parseJSON function. If available, this function calls the native
window.JSON.parse. Unfortunately, the later function, when called on the
single space we got earlier, raises a SyntaxError. (It does the same on
an empty string.)

I take it, the browser (Firefox 3.5.11) is to blame, but that doesn't
help much. The easiest solution would be if jQuery didn't pass entirely
whitespace strings to window.JSON.parse. As a stop-gap measure, I'm
patching jQuery like this

  var parseJSON_orig = $.parseJSON;
  $.parseJSON = function(data) {
    if (/^\s*$/.test(data)) {
      return null;
    } else {
      parseJSON_orig(data);
    }
  }

Is there any better way to get things working? Should jquery-ujs take
care of this problem?

Michael

No
It's jquery bug