Another spin-off from the website: a permalink_fu improvement that allows dynamic permalinks. I know it is an oxymoron, because permalinks should be .. well .. permanent! And because search engines index them, they should never change. But what happens when you publish something, your permalink is generated with permalink_fu using the title of your post, and after a couple of days you want to change the title, and the permalink under which the post is accessible as well?

Following the specification, your app should send out a 301 moved permanently HTTP status when accessing the old permalink and redirect the client to the new Uniform Resource Locator. That’s quite the same thing what my modification to permalink_fu does: whenever your post attributes are changed, the former and new permalinks are saved to the database, and you can enable your controller to generate 302 moved temporarily redirects when needed. In other words, it checks whether the requested URL is an old permalink, and automagically redirects the client to the new one.

Everything is done behind the scenes, and the plugin has also got nifty rake tasks to set up the Redirect model and associated migrations. And you can change its name, of course! :)

The 302 code was chosen because the 301 permanent status code has quite disruptive effects on search engines, but more discussion is welcome.

Have a look over my repository at github, read the README that contains the documentation of the added features, and check out the code!

I recently wrote jQuery plug-in, that allows AJAX file uploads without using a fixed file input button. It achieves its goals by installing an OnMouseMove handler over the selected elements, and moving the input button under the mouse cursor.

The quote that inspired this code is: “If Muhammad won’t go to the mountain, the mountain will come to Muhammad”, the opposite of the more known proverb :).

EDIT 2023: CAUTION: these links are expired :-( It has been spinned off from the Visita CSA application JavaScript codebase, see the gist for more information, and have a look onto the live app code for an example of its usage.

Here is the source code:

//  ~ JavaScript Kung-FU, with an excess chunky bacon dose! ~
// This plugin allows seamless ajax file uploads without having
// a fixed file input button. It achieves this by installing an
// OnMouseMove handler over the interested elements, and moving
// the input button under the cursor. <<If Muhammad won't go to
// the the mountain, the mountain will come to Muhammad.>> :-).
// This approach is needed on the majority of browser, except
// Safari, on which the coder is allowed to trigger a "click" 
// event onto an input type=file element. On other browsers,
// you can not, that's why the complicated mousemove approach
// was chosen.
// Either way, when the value of the input type=file changes,
// handlers are disabled, and a user-provided callback is then
// called (passed via the "upload" option). Handlers are then
// re-enabled again when the upload succeeds or fails.
// IE has additional problems, because, quite unexplicably,
// when submitting a form that causes a page load, the change
// event on the file input is triggered AGAIN, thus triggering
// a new file upload. To circumvent this, you can pass a "linked" 
// option, that contains the jQuery selector of the form, and
// whenever an input under this form is hovered, ajax upload
// handlers are temporarily cleared and thus the spurious form
// submission.
// The jquery Form plugin is a perfect companion of this one,
// because of its .ajaxSubmit method. Have a look at its home
// page:
// Have fun!
// -
$.fn.ajaxFormUpload = function(options) {
  var positioning = { top: 0, left: 0,
    position: 'absolute', cursor: 'pointer', 'z-index': 2 };

  var form = $(options.form || '#ajax_upload');

  var input = form.find('input[type=file]');
  input.css($.extend(positioning, { width: '10px', opacity: 0, 'font-size':'0px' }));

  var hovering_element = null;

  var elements = $(this);

  var handler, event_;
  if ($.browser.safari) {
    event_ = 'click', handler = function() {
      hovering_element = $(this);;
  } else {
    event_ = 'mousemove', handler = function(event) {
      hovering_element = $(this);
      form.css({ left: event.pageX - 10, top: event.pageY - 5 });

  function enable()  { $(elements).bind(event_, handler);   }
  function disable() { $(elements).unbind(event_, handler); }

  input.change(function() {
    var element = hovering_element;
    if (!element) return;

    options.upload(element, form);



  if (options.linked) {
    $(document).ready(function() {
      $(options.linked).find('input').mouseover(function() { hovering_element = null; });

You can check it out on github.

When you install the developer beta of Windows 7, after the usual 3 reboots cycle, you are greeted with the following image:

The Betta Siamese Fighting Fish

It is the Siamese fighting fish, a beautiful tropical fish, but with an interesting characteristic: it is extremely aggressive. It is popular belief that two males fight themselves even in the wild, but that’s not quite true. This belief descends from the behaviour of the fish into an aquarium, where the victor continuously attacking the loser, eventually causing the loser’s death.

Now, think about the software ecosystem as an aquarium. And think about Microsoft into this aquarium. The latest release of Microsoft OS has an aggressive fish as its default skin, and it is alone in this aquarium. And there’s no place for anyone else: they’ll fight whoever adversary, even if it’s from the same species.

What’s uncertain is .. they’ll succeed, or not? :). We’ll see!

au lab pwnz

The right session shows a document open on an aggregate audio device between soundflower (2ch) and a Creative SBLive with 6 channels: the flower receives sound input from iTunes and routes it to the card channels, using all the 6 speakers.

Effects have been added to improve the audio experience (details here: The right session also uses AUNetSend to stream audio onto the left session, connected to the built-in speakers of the macbook.

Result: stereo audio being played on eight channels. Audio Units are a really powerful instrument, well coded and well working.

[tks nextie for telling me about AUNetSend and AUNetReceive]

UPDATE 19-12-2008

au lab pwnz again

Improving: there is no need to use NetSend and NetReceive to play on 8 speakers: an aggregate device composed of Soundflower 2ch, the USB 6ch SBlive and the Built-in output is enough!

Also, note the new bus: it’s required because the AUMatrixReverb effect added to the center channel to improve the audio stereophony actually takes two channels, so it overlaps with the following one (the LFE). But applying the effect to a bus does not exhibit this side effect.

Result: excellent 7.1

Exactly the words that run around my mind these days:

When we reach the point where online anonymity has ended, instead of getting to be who we really are, the fact that we’ve become so aware of the fact that we’re always being recorded, photographed, tracked, and traced, will have actually created a slightly altered personality instead. Like reality TV show contestants, the act of being observed will change our behavior. Our personal brand image will become our public identity and therefore our identity.

I’d think these describe exactly the “facebook effect”.

What do you think?