Category: Software Development

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Remote control of XBMC, but not too much

Yesterday and today I have scripted a small web interface for remote control of XBMC using its HTTP API. (BTW, That API could really use a redesign!)

It’s actually just a page showing a screen shot and the name of the file that is currently playing, together with some commands to remote control XBMC.

Available commands are pause/resume, stop, play another file, and shutdown.

I also implemented support for showing notifications on the XBMC screen, which gave me an idea:

The Google Calendar can e-mail reminders for appointments. If XBMC is running, the reminder could be shown as a notification on the XBMC monitor.

I was just about to start implementing this calendar-reminder-in-XBMC when I reminded myself that there are many other small and big projects that would be more valuable for me. But instead of throwing this idea right down the trashcan I decided to blog about it first. Done!

Now I’ll spend some valuable time with my son!

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Today’s thoughts about programming languages

Maybe some of you have heard me ranting about this already?

  • I’m not productive enough in C++ and I feel too limited by Java
  • A large chunk of Java frameworks seem to serve no other purpose than to workaround limitations in Java
  • I believe (and hope!) that Java will cease to be the default language in the non-Microsoft world, and that other JVM-based languages such as Scala, Groovy and JRuby will become more important
  • How can I convince a client to allow Scala, Groovy or JRuby in a project?
  • I should really get some C# experience!
  • It seems like I almost always resolve to PHP when I need to get something done quickly… which reminds me of an upcoming blog post about a recent fight with SoapServer and SimpleXML to implement WSSE UsernameToken authentication.
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TaskFreak hacking part 2: date format

My TaskFreak hacking goes on. In Sweden we often use ISO 8601 format for dates (year-month-day), but TaskFreak does not offer this out of the box.

Most date formatting comes from the DATE FORMATS section in include/config.php but even after changing these date formats I still don’t get all dates displayed as I would like.

For example, the text box for the date when editing an item is using the TZN_DATE_FRM constant defined in include/classes/tzn_generic.php. There’s a pretty naïve comment in the source code, saying that there is a “US format” for dates and a “rest of the world” format. Fortunately (for the US), the rest of the world is not united in opposition.

To get the date format I wanted I changed the constant definition like this:

define("TZN_DATE_FRM","%Y-%m-%d");
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Hire me for my mind!

Ward Cunningham tweeted a link to an ad for an Agile Ruby Developer at AboutUs, Inc. Out of curiosity I took a look and it sounds like a fantastic opportunity for someone!

What I liked most about the job ad was the last part:

We’re hiring you for your mind. Please showcase it by answering some of the following questions in your cover letter:

  • What is a recent programming insight you discovered and what was intriguing about it?
  • Why do you want to work with us? (be specific!)
  • What Open Source communities/projects are you a part of and why do you like them?
  • Tell us about a time you brought initiative to your team and made a positive change.
  • What modern programmer do you admire and why?
  • How do you learn and keep up with the field of computing?

These questions really appeal to me!

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Good at programming, bad at communicating

I can’t remember how I originally found the link (was it in someone’s tweet?) but I managed to find it again in order to share it here. The message may seem silly in retrospect, but I think it was enlightening. The article is called Sometimes, The Better You Program, The Worse You Communicate. The author writes that:

[…] good programming practices are directly opposed to good communication practices.

In bullet form:

  1. D.R.Y. Does Not Apply.
  2. Humans don’t mean what they say.
  3. Compilers don’t need to see an example.
  4. Programs love definitions; Humans get flummoxed.

From now on I will try to repeat myself more often, act on what people mean and not what they say, give more examples and avoid definitions. Except when programming!

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Permute an array in PHP

I wrote this function recently when I could not find it in the PHP function list. Please provide any optimizations you discover!

function permute($array)
{
  $results = array();

  if (count($array) == 1)
  {
    $results[] = $array;
  }
  else
  {
    for ($i = 0; $i < count($array); $i++)
    {
      $first = array_shift($array);
      $subresults = permute($array);
      array_push($array, $first);
      foreach ($subresults as $subresult)
      {
        $results[] = array_merge(array($first), $subresult);
      }
    }
  }
  return $results;
}

assert(permute(array()) == array());
assert(permute(array(1)) == array(array(1)));
assert(permute(array(1,2)) == array(array(1,2),array(2,1)) ||
       permute(array(1,2)) == array(array(2,1),array(1,2)));
assert(count(permute(array(1,2,3)) == 6));
assert(count(permute(array(1,2,3,4)) == 24));
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Amount of type checks in Java

Martin Fowler writes about DynamicTypeCheck:

Recently some of our developers ran into the accusation that with a dynamic language like ruby you use so many dynamic type checks that you end up effectively writing your own type system. So they thought, since we’ve written a lot of real ruby code – how often do we make dynamic type checks?

…

We define a dynamic type check as the use of the methods is_a?, kind_of?, and instance_of?.

This made me think about the use of instanceof in Java. A pretty non-scientific investigation of an Open Source Java application (Vuze) showed:

Lines of code: 740257 (find . -name '*.java' | xargs cat |wc -l)

Number of instanceof: 1926 (find . -name '*.java' | xargs cat| grep -c ' instanceof ')

LOC/Number of instanceof: 384

So, there is actually more instanceof in this Java project than there are dynamic type checks in the anonymous Ruby projects used for the statistics presented by Martin Fowler. I certainly hope it wasn’t a Java developer that accused dynamic languages to use lots of dynamic type checks!