Another spin-off from the www.visitacsa.it 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.

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 spun off from the Visita CSA application JavaScript codebase, see the gist for more information, and have a look at 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 browsers, 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: http://malsup.com/jquery/form/.
// 
// Have fun!
// - vjt@openssl.it
//
$.fn.ajaxFormUpload = function(options) {
  var positioning = { top: 0, left: 0,
    position: 'absolute', cursor: 'pointer', 'z-index': 2 };

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

  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);
      input.click();
    };
  } 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;
    disable();

    options.upload(element, form);

    enable();
  });

  enable();

  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:

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 each other even in the wild, but that’s not quite true. This belief descends from the behaviour of the fish in an aquarium, where the victor continuously attacks the loser, eventually causing the loser’s death.

Now, think about the software ecosystem as an aquarium. And think about Microsoft in 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 whatever adversary, even if it’s from the same species.

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

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: http://www.rottenbrains.com/?p=232). 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¶

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.

Exactly the words that run around my mind these days:

http://www.readwriteweb.com/archives/the_end_of_online_anonymity.php

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 think these words describe exactly the “facebook effect”.

What do you think?

If you’re wondering why the CCacheServer daemon, that caches in memory Kerberos tickets obtained via kinit(1) is NOT starting .. that’s because of a strange bug regarding the LimitLoadToSessionType specified in the agent .plist, located into /System/Library/LaunchAgents/edu.mit.kerberos.CCacheServer.plist on OSX 10.5 systems.

You simply have to comment out these two lines:

<key>LimitLoadToSessionType</key>
<string>Background</string>

And either

launchctl load /System/Library/LaunchAgents/edu.mit.kerberos.CCacheServer.plist

or reboot your system ;).

CCacheServer will then be instantiated when you do a kinit:

$ kinit
Please enter the password for vjt@DOMAIN.LOCAL:

$ klist
Kerberos 5 ticket cache: 'API:Initial default ccache'
Default principal: vjt@DOMAIN.LOCAL

Valid Starting     Expires            Service Principal
11/12/08 20:59:35  11/13/08 06:59:14  krbtgt/DOMAIN.LOCAL@DOMAIN.LOCAL
    renew until 11/19/08 20:59:35

The bug is strange because the LimitLoadToSessionType key actually should instruct launchd to automatically start up the daemon and run it once for every logged in user, when kinit asks its services. But, if the key is set in the .plist, a launchctl load on it fails with “nothing found to load”. Weird!

If you use github-provided lighthouse integration, from the “Admin” pages of your git repository, you may have stumbled upon a glitch: every changeset on lighthouse appears as done by the lighthouse user that configured the integration on github.

This happens because lighthouse uses the API token to link changeset authors to LH users, and that’s not good when you’re not alone committing :-).

A simple solution is to use a post-commit hook, as described here, but that’s not satisfactory because it means that every time you issue git commit on your console, the commit message will go public, and if you --amend or reset --soft the index you’ll have to browse to lighthouse and delete the changeset.

A much smarter solution is to push all changed revs when pushing them to github: I modified the original post-commit hook and installed it alongside the git command in $(dirname which git)/git-lh.

This gives me a new git lh command that fetches the current HEAD revision from github using refs/heads/master and POSTs every changeset between that rev and the current tip in the working tree to lighthouse.

So, if you issue git lh before issuing git push, every change you’re pushing to github will go to lighthouse, too.

UPDATE: A simple bash script like:

#!/bin/bash
git lh && git push

saved as git-lh-push saves you from typing two commands when you want to push :).

When things in your life seem almost too much to handle, when 24 hours in a day are not enough, remember the mayonnaise jar and the 2 glasses of wine.

A professor stood before his philosophy class and had some items in front of him. When the class began, he wordlessly picked up a very large and empty mayonnaise jar and proceeded to fill it with golf balls. He then asked the students if the jar was full. They agreed that it was.

The professor then picked up a box of pebbles and poured them into the jar. He shook the jar lightly. The pebbles rolled into the open areas between the golf balls. He then asked the students again if the jar was full. They agreed it was.

The professor next picked up a box of sand and poured it into the jar. Of course, the sand filled up everything else. He asked once more if the jar was full. The students responded with a unanimous “yes!”

The professor then produced two glasses of wine from under the table and poured the entire contents into the jar effectively filling the empty space between the sand. The students laughed.

“Now,” said the professor as the laughter subsided, “I want you to recognize that this jar represents your life. The golf balls are the important things – your family, your children, your health, your friends and your favorite passions – and if everything else was lost and only they remained, your life would still be full. The pebbles are the other things that matter like your job, your house and your car.”

Today we released the output of 9 months of hard work: myousica.com, a social networking site for musicians. Have a look at the promo video and check out the site. Have fun! :)

UPDATE 2009/02/23: The site is now paused.

UPDATE 2010/10: The source code has been released on GitHub under the name Mewsic.

Myousica timeline: Launch announcement (2008) • Open-sourcing the Rails app (2010) • Multitrack editor (2010) • Audio pipeline (2010) • Eighteen years later (2026)

javascript, klingon, javascript, javascript, IE, IE, IE, sucks, optimize, optimize,
user experience, web2.0, harnessing collective intelligence, love, hate, sex, ruby,
rails, rails, rails, admin, REST, javascript, javascript, IE IE IE SUCKS, premature
optimization, assets, google API, love, love, hate, hate, air, trips, hide, toggle,
show, ryan, twenty-three times the pain, javascript, IE, ruby, rails, CSS, spacing,
position:absolute, love, love, love, love, too much, too much, too much.

number 42.