Development

The past days I’ve been posting stories with a few code samples – Perl, PHP, Javasscript and/or HTML. While Wordpress is fantastic to a number of things, handling sourcecode examples in the posts, reallly isn’t one of them.

I’ve been playing with a number of plugins, but none of them really works for me. What I’m looking for is this:

• It must be able to handle HTML, Javasscript, PHP and Perl sourcecode.
• The code samples should work with the visual editor (preferably entered in this, but ”code mode” is quite alright) – Visual post editing shouldn’t break the code example.
• The plugin should be alive (maintained and tested with recent wordpress releases).

I would have thought it would have been easy to find a plugin that covered the above requirements, but so far I’ve had very little luck – any suggestions?

Sometimes you might need to change the address a form submits to, it’s quite easy with javascript. One example could be if you - like me - from time to time is hit hard by comment-spammers. Changing the submit URL on the form with javascript, makes it at least somewhat harder for “automated brainless robots” to kill your site in a spam attack.

The recipie below is a very simple example, but so far it seems to work quite well:

<script type="text/javascript">
function doSubmit() {
  var target1 = 'hello';
  var target2 = 'world';
  var target3 = '.cgi';

  var supertarget = target0 + target1 + target2 + target3;
  var theForm=document.getElementById("theForm");
  theForm.action = supertarget;
  theForm.submit();
}
</script>

<form id="myForm" method="post" action="some\_fake\_address.php">
<input type="text" name="dummy field" value="">
<input type="button" onclick="javascript:doSubmit();">
</form>

Suppose you’ve just filled you digital camera with an endless stream of photos. You want to place them online at your website, but placing 5+ megapixel files online, well…probably a bad idea. Let’s resize them to a propper size - and why not use Perl and ImageMagick for the job.  Not a problem, here’s a complete example on how to resize all images in a directory . Make sure you have ImageMagick installed.

I’m sure most people only thing of PHP as a Weblanguage due to be called through a browser. It has however since version 4.3.0 also been possible to use PHP on the commandline - as you do with Perl, Shell scripts and likewise. If you’re using Linux (or an other Unix-like operating system - including Mac OSX) you probably have a few small programs available which can make it a breeze to check if the syntax in all you PHP scripts is correct.

Changing files from one format to another is quite easy with a little bit of ImageMagick . In the example below a JPG image (test.jpg) is converted into a GIF-image (test.gif). To output in a different (ImageMagick supported ) format, just change the “image->Set” line.

#!/usr/bin/perl -w use strict; use Image::Magick;
my $image = Image::Magick->new();

# To explicitly set image format use this instead: 
# my $image = Image::Magick->new(magick=> 'JPEG');
my $x = $image->Read('test.jpg'); 
$x = $image->Set(magick => 'GIF'); $x = $image->Write('test.gif');
exit();

If you need for figure out the size of an image, fetch Image::Size from CPAN , it’s just what you need. The module recognizes the most common image-formats such as JPG, GIF, PNG, PSD, TIFF and plenty more. The interface is simple and will get you what you need with no trouble at all.

 #!/usr/bin/perl -w use strict; use Image::Size;

# Just fetch the size 
my ($size_x, $size_y) = Image::Size::imgsize('test.jpg'); 
print "Image is: $size_y x $size_x (height x width)\n";

# HTML-friendly format 
my $size = Image::Size::html_imgsize('test.jpg'); 

exit();

If you have the GD extension available, you can do a few useful things. One of the simple things is getting an image size is a simple matter. You can either fetch the height and width in seperate variables – or even fetch the height and width in a string pre-formatted for use in an image tag.

Here’s the example in source:

$load\_ext = get\_loaded\_extensions();

if (!in\_array(gd, $load\_ext)) {
    echo "GD is NOT available";
    die();
}

$nikonFile   = './aarhus\_demo\_photo.jpg';
list($width, $height, $type, $img\_txt)  = getimagesize($nikonFile);

echo "The image is ".$width . " by ".$height."\\n";
echo "![]($nikonFile)\\n";

Within most photos from digital cameras besides the actual image, there’s a little ”information block” call EXIF data. If you have the correct PHP extension installed on your server – the one called ”exif” – it’s pretty easy to read the EXIF data and display them, as you like.

First, let’s check if the extension is available?

$load\_ext = get\_loaded\_extensions();
if (!in\_array(exif, $load\_ext)) {
echo "Exif is NOT available";
} else {
echo "Exif extension is available.";
};

If you’re doing some basic profiling of your PHP scripts, the build-in microtime function can help you make some simple benchmarking fast. Here’s a rough example to show you how it could be used. The doSomething function is the function we want to benchmark.

$time = microtime();
$time = explode(' ', $time);
$time = $time\[1\] + $time\[0\];
$start = $time;

doSomething();

$time = microtime();
$time = explode(' ', $time);
$time = $time\[1\] + $time\[0\];
$finish = $time;
$total\_time = round(($finish - $start), 6);
if ($debug) print ("<p>Processing took approximately $total\_time seconds</p>");

Some websites require access control, and sometimes you may need to generate a password for a user. Here’s a simple function that can do just that.

The $base-variable contains the characters allowed in the password. The supplied string may be changed, but the selected charaters should exist on all keyboards (as far as I know). When calling the function, you can specify the lenght of the password you want. Simple, right?

function makePassword($desiredLenght = 8) {
    $password = '';
    $base = 'abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789';

    for($i=0;$i<$desiredLenght;$i++) {
        $password .= $base\[(rand(0, (strlen($base)-1)))\];
    }
    return $password;
}