Archive for the 'Software' category

TickTweet WordPress plug-in

published on November 21, 2008.
Heads-up! You're reading an old post and the information in it is quite probably outdated.

Few weeks ago @imjustcreative mentioned on Twitter that he would like a WordPress plug-in that would scroll (tick) tweets where “soultweet” is mentioned. As I wanted to do a plug-in for some time, but never had any good ideas, I told him that I’ll take up the job. So I started to work on this in my free time.

Before I even started looking at anything, I decided that I want this plug-in to be fast, to work with smallest possible data to save bandwidth and to keep the number of calls towards Twitter low.

First I looked into the Twitter Search API documentation, to see how data can be retrieved from Twitter — in Atom or in JSON.

The first idea...

As a JSON document is smaller than an XML document, I decided to retrieve data in JSON. Of course, once retrieved it would be cached locally in a file for some time (5 minutes is my default).

I also wanted to avoid the possibility of the page waiting to retrieve the data from Twitter, so I figured that it would be the best to call it up with Ajax. That way, when the plug-in is called up, it sends an Ajax request to himself, the page continues loading normally and in the background runs the Ajax request.

The draft was there, I looked at the WordPress writing a plug-in page and in a week or so the first version of the plug-in was ready to go out.

I tested it locally on my Windows machine (a basic WAMP setup) and on my Ubuntu machine (a basic LAMP setup), on this server and on another one which has a ton of security limitations (server of my College). I was glad to see that it worked like a charm on all 4 servers. I put up a TickTweet page, and let it out in the wild through Twitter.

The retweet madness started immediately. @imjustcreative, @jonimueller and @bishop1073 downloaded it right away. Soon as they enabled the plug-in, the short and exciting life of TickTweet started to end. Errors, bugs… Joni’s server is running on PHP 4, and I had a few PHP 5 only functions. My bad. On Graham’s and Bishop’s server who knows what went wrong. Graham helped me a lot tracing down the bugs, a few of them were found and squashed, but that was not enough. So I decided to pull back TickTweet, rethink it and possibly rewrite it.

The second idea...

OK, this JSON — Ajax thingy won’t work. Back to the paper. I started looking at the WordPress core to see what functions and/or classes are available in it for this kind of task… Didn’t took me long to find the fetch_rss() function. Man I was happy to find that! It’s using the MagpieRSS and the Snoopy classes to retrieve the data. I figured, those are included in WP’s core, they’re gonna do the job just fine. So I’ve rewritten it.

Testing again. The College’s server was dropped out right away, no way around that security. On others it worked fine. I tested for a couple of days just to make sure. When I thought it was OK, I’ve let it go once again. I contacted Joni, Graham and Bishop to tell them that the new rewritten version is out. On Joni’s site it worked. Awesome. On Bishop’s site worked. Kinda. On Graham’s site didn’t work. He tried it on another site. Worked. Cool. Finally it works. I was happy.

But not for long. The next day I saw that on my site it’s ticking some ol’ tweets. What?! Then started the bug hunting again. I looked at each line of code, var_dumped every variable. No luck. Somehow, all of a sudden, my server is not getting the data from Twitter. No changes on the server configuration, no change in the code, but it just won’t work.

The third idea...

The third idea is to leave this “plug-in” as—is, and to stop working on it. It just doesn’t pay off. Sure, I could trace down where it hangs on my server, going backwards through the code, but it’s just not worth it. Those who are interested in this plug-in, you can find it at the TickTweet page, use it, rewrite it, change it, trash it.

Cheers!

Powered by WordPress 2.7 beta 1

published on November 04, 2008.
Heads-up! You're reading an old post and the information in it is quite probably outdated.

I’ve decided to upgrade to WordPress 2.7 beta 1, just for fun. For now, no major problems occurred, just a few smaller ones, all which are caused by my hacking of the WordPress core — I wasn’t keeping track of all hacks I did, so there were some random errors, but everything should be fine now.

I don’t recommend to no one upgrading to this version, unless you are OK with possible problems caused by this beta version. And even if you decide to upgrade now, do a backup of your database! Heck, do 2 backups!

First I did was backing up… No, I lie. First I did was start copying files of the wp-admin folder up to the server, when it came to my mind that I forgot to backup the database. Silly me. While it was copying I did a backup. Then I copied the contents of the wp-includes folder and then the files under the root folder of my blog. I haven’t uploaded nothing from the wp-content folder.

Oh yeah. Under the root folder, skip copying one file (if it’s there): the wp-config.php file, just to prevent overriding the configurations.

I tried to login to the dashboard. A message waited me, saying something like the database needs to be upgraded, blablabla, with a big a button. So I pressed the button. And everything went well. I logged in to the dashboard, to find out that I can finally find my way around the dashboard. It’s soooo much better now!! Errmm… I even saw a screenshot of it some where on the Internet… Meh. Can’t find it now.

After fixing those little errors I saw that my custom made template is working just fine and the plugins too — all 3 of them.

So there. My blog is now powered with WordPress 2.7 beta 1. I thought to write a tutorial on upgrading from WP 2.6.x to WP 2.7 but as it all comes down to uploading the files and hitting that “Upgrade database” there is no need for a tutorial.

Oh, and in case you missed it: do a bloody backup first!

Cheers!

P.S.: If someone finds some errors or the blog starts misbehaving let me know! Thanks!

Tags: blog, upgrade, wordpress.
Categories: Blablabla, Free time, Software.

A Zend_Captcha example

published on October 22, 2008.
Heads-up! You're reading an old post and the information in it is quite probably outdated.

Update: I made an error in the example code, regarding the CAPTCHA image URL. I’m sorry for any troubles caused by this mistake.

Update #2: Here’s an example of using Zend_Captcha without the whole Zend Framework stuff.

Update #3: There was an unintentional error in the captchaAction() method, Adam warned me about it in the comments. The error is fixed now. Thanks Adam.

OK, this was a bit tricky and I found no examples about it, so I thought to blog it. I’ll just show a quick example how to implement Zend_Captcha into a Zend_Form, may be useful for someone. There are several CAPTCHA types in ZF, like the Image, Figlet and Dumb. I use Image.

First of all, we’ll use sessions, so we need to change the bootstrap file a little:

<?php
// Put this line somewhere after the Zend_Loader::registerAutoload(); line
Zend_Session::start();

We need to start the session to use it, putting it close to the top will assure that there will be no “Headers already sent by…” errors caused by a wrongly placed session start.

Next we need a folder which has a 777 permission on it (Windows users, you can skip this… Or start using GNU/Linux) where we will put our captcha images for a while… This folder must be in the public folder somewhere. So create one.

How does this work? When a captcha is generated, it generates a unique ID (e.g. 539e517b0c0f4e32ef634dae92f07f77) and the word on the image. That unique ID is used for the file name of the image and for the session namespace (the namespace is like: Zend_Form_Captcha_uniqueId), so it knows which image belongs to which session. Also, the generated word is placed inside it’s own session. That ID is placed on the form in a hidden field, so when the submission is received, we can access the ID and recreate the correct session namespace and access the data in it: the word on the image.

Awesome. Now, to the fun part. I use the Zend_Form_Element_Captcha class, so no additional fooling around is needed to put the captcha in the form. Here’s the code:

<?php
public function indexAction()
{
// Our form object...
$form = new Zend_Form();
// And here's our captcha object...
$captcha = new Zend_Form_Element_Captcha(
        'captcha', // This is the name of the input field
        array('label' => 'Write the chars to the field',
        'captcha' => array( // Here comes the magic...
        // First the type...
        'captcha' => 'Image',
        // Length of the word...
        'wordLen' => 6,
        // Captcha timeout, 5 mins
        'timeout' => 300,
        // What font to use...
        'font' => '/path/to/font/FontName.ttf',
        // Where to put the image
        'imgDir' => '/var/www/project/public/captcha/',
        // URL to the images
        // This was bogus, here's how it should be... Sorry again :S
        'imgUrl' => 'http://project.com/captcha/',
)));
// Add the captcha element to the form...
$form->setAction('/index/captcha/')
        ->setMethod('post')
        // Add the captcha to the form...
        ->addElement($captcha)
        ->addElement('submit','Submit')
// Pass the form to the view...
$this->view->form = $form;
}

On the other side, it goes something like this:

<?php
public function captchaAction()
{
  $request = $this->getRequest();
  // Get out from the $_POST array the captcha part...
  $captcha = $request->getPost('captcha');
  // Actually it's an array, so both the ID and the submitted word
  // is in it with the corresponding keys
  // So here's the ID...
  $captchaId = $captcha['id'];
  // And here's the user submitted word...
  $captchaInput = $captcha['input'];
  // We are accessing the session with the corresponding namespace
  // Try overwriting this, hah!
  $captchaSession = new Zend_Session_Namespace('Zend_Form_Captcha_'.$captchaId);
  // To access what's inside the session, we need the Iterator
  // So we get one...
  $captchaIterator = $captchaSession->getIterator();
  // And here's the correct word which is on the image...

  $captchaWord = $captchaIterator['word']
  // Now just compare them...
  if($captchaInput == $captchaWord)
  {
  // OK
  }
  else
  {
  // NOK
  }
}

Easy, ain’t it?

Happy hacking :)

Tip: Using a monospace or a serif font for the words on the image (like FreeMono.ttf found by default on Ubuntu), makes the word quite unreadable — with the FreeMono.ttf about 8 out of 10 is UNreadable — so use a sans-serif font.

Starting with Zend Framework - part 2

published on October 20, 2008.
Heads-up! You're reading an old post and the information in it is quite probably outdated.

This post is the second part of my introductory text on Zend Framework, Starting with Zend Framework. This time I cover the basics about controllers, actions, view scripts and view helpers. On request routing and the Front Controller I will write one (or more) big post(s), so this part won’t be explained now. I will also skip explaining the models; they deserve their own post :)

If anyone is into writing a guest-post on models, let me know!

The Controllers

The Controllers are the heart of every MVC based application. They control the execution of the application, what to do with the data, what to show the user, what to write to the database, etc. The Controllers that you will write all the time, are called Action Controllers. These Controllers subclass the Zend_Controller_Action abstract class. Every application module must have a default Controller, which will be accessed if no specific Controller is requested. The default name for this default Controller is Index. Examples of the IndexController and FooController:

<?php

// The IndexController class must be placed in the controllers folder
// and saved as IndexController.php
class IndexController extends Zend_Controller_Action
{
    public function init()
    {
    }

    public function indexAction()
    {
    }
}

// The FooController class must be placed in the controllers folder
// and saved as FooController.php
class FooController extends Zend_Controller_Action
{
    public function init()
    {
    }

    public function indexAction()
    {
    }

    public function barAction()
    {
    }

    public function someRandomFunctionDoingSomeFunkyStuff()
    {
    }
}

The Controllers must contain at least the indexAction() function; the others are arbitrary. I always have an init() function, in which I setup the cache object, call up the models, etc. Controller names that are not in the “default” module, must be prefixed with the Title-cased name of the module and an underscore:

<?php

// An example of the IndexController in the
// dummy module
// The file name remains IndexController.php!!!
class Dummy_IndexController extends Zend_Controller_Action
{
}

// An example of the FooController in the
// dummy module
// The file name remains FooController.php!!!
class Dummy_FooController extends Zend_Controller_Action
{
}

The actions

Actions are methods of the Controller class. Use them to do some specific task: show users, list news, insert to database (the actual INSERT SQL statement should be in the model), etc. As stated before, every Controller must have an index action — this one is called if no specific action is requested. By default the view object is instantiated, so if you don’t turn it off, you must create a view script with the same name as the action (without the “Action” word) in the views/scripts/foo/ folder.

Assigning variables to the view scripts is simple:

public function indexAction()
{
    $this->view->someVariable = "some value...";
}

The view scripts

View scripts are, well, for viewing. This is the only place where you should have statements like echo and print. The default templating engine is PHP itself, but it’s possible to change it to something like Smarty. I leave PHP; it has everything for templating, so why would I change it? The default file extension for view scripts is “phtml” — but as with everything, this can also be changed :)

Getting variables that are assigned from the action:

// Output: some value...
<?= this->someVariable ?>

The view helpers

The view helpers are simple classes that help in view scripts with things like formatting dates, creating links, etc. Here’s an example view helper that I use to show dates in “Serbian” format:

File name: views/helpers/SrDateFormat.php
<?php
/**
* View helper for returning dates in Serbian format
* dd.mm.yyyy.
*
*/
class Zend_View_Helper_SrDateFormat
{
    public function srDateFormat($dateToFormat)
    {
        return date('d.m.Y.', strtotime($dateToFormat));
    }
}

Usage is quite simple:

// somewhere in some view script...
<?= $this->srDateFormat($someDateToShow); ?>

Bringing it all together

Just for an overview, here is an example of a Foo Controller in the Dummy module with index and bar actions and their view scripts.

<?php
// File name: application/dummy/controllers/FooController.php
class Dummy_FooController extends Zend_Controller_Action
{
    public function indexAction()
    {
        $this->view->sayHello = "Hi there!";
    }

    public function barAction()
    {
        $this->view->sayHelloAgain = "Hi here :)";
    }
}

And the view scripts:

<!-- File name: application/dummy/views/scripts/foo/index.phtml -->
<h1>Saying hello</h1>
<?= $this->sayHello ?>

<!-- File name: application/dummy/views/scripts/foo/bar.phtml -->
<h1>Saying hello again</h1>
<?= $this->sayHelloAgain ?>

So if you direct your browser to “http://example.com/dummy/foo/&#148; or to “http://example.com/dummy/foo/bar&#148; you should get the “Saying hello” or the “Saying hello again” page…

This would be my introductory text to Zend Framework. Hope it’s not confusing and is easy to follow. I just want to help newcomers to ZF help settling in easily :) For a tutorial application with ZF, I recommend Rob Allen’s Zend Framework tutorial.

In the coming days/weeks I’ll write a detailed post about the Front Controller, so if you wish, grab the feed or subscribe by E-mail to stay tuned.

Cheers!

Ubuntu as a dev machine

published on October 15, 2008.
Heads-up! You're reading an old post and the information in it is quite probably outdated.

This post is more of a note to myself, ‘cause I keep forgetting all these Linux commands, and spend hours setting up stuff right…

I’m installing Ubuntu 8.04 on VirtualBox, with windows xp as the host machine. I must do it this way, because my wireless card is having some problems with Linux, something with the drivers. The possible solution includes kernel compiling — thanks, but no thanks.

Anyway… The installation itself is no trouble, so I’ll skip that. I always keep the apt-cache from previous installations, sparing hours of updating the system… On the host I have a folder that I share between the host OS and the client OS and first I need to reach that folder, to get from it the apt-cache.

First, need to install the Guest Additions. In Virtualbox go to Devices —> Install Guest Additions. In the console run:

sudo /media/cdrom/VBoxLinuxAdditions.run

After it’s finished, we need to mount the shared folder:

sudo mount -t vboxsf name_of_the_sharing_folder /path/to/mount_point

Now, for me, this command shows some error. Here’s what I have to do:

sudo modprobe vboxfs
sudo mount -t vboxsf name_of_the_sharing_folder /path/to/mount_point

Something with some modules not being loaded into the kernel, not bothered with it really… Now I can copy the apt-cache to where it needs to be:

sudo cp -r /path/to/mount_point/apt-cache /var/cache/apt/archives

Now do the system update. If the system update includes a kernel update, you’ll have to install Guest Additions once more…

Next installing the LAMP:

sudo apt-get install apache2
sudo apt-get install php5 libapache2-mod-php5
sudo /etc/init.d/apache2 restart
sudo apt-get install mysql-server
sudo apt-get install libapache2-mod-auth-mysql php5-mysql phpmyadmin
sudo /etc/init.d/apache2 restart
sudo a2enmod rewrite
sudo /etc/init.d/apache2 restart

That should do it. But hey! mod_rewrite still doesn’t work!

sudo gvim /etc/apache2/sites-available/default

And change AllowOverride None to AllowOverride All.

There. I have a basic LAMP on Ubuntu under VirtualBox. I made a few snapshots of the VirtualBox image, in case I trash it (which probably will happen soon), so I don’t need to reinstall over again.

Now, I’m of to setup SVN…

Robert Basic

Robert Basic

Software engineer, consultant, open source contributor.

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