I can’t say I learned a lot at school, but I did pick up a few tips that helped me polish up my self-taught coding technique.

During my study of software engineering, my instructors always stressed two things: modular design and documentation. Simple, yet excellent concepts that will save you–and anyone after you–hours and hours of time. I’ve been applying these principles to all of my code ever since I learned about them, but I’ve only recently begun to understand just how important they really are.

I’ve been working with some very unmodularized and undocumented code recently, and I’ve begun to develop an immense dislike for the original author. I’m supposed to add simple little features here and there. By themselves, the features are simple–around 10 to 100 lines each–and would take maybe 10 minutes each to write. To add them to a well-documented, modular coded project might take an hour or two including some testing. But incorporating these tiny features into an existing project base consisting of unmodularized and undocumented code takes 10 to 20 times that. Believe me, I know from experience. I am faced with the constant urge to rewrite the entire code base from scratch. I know it would take longer to rewrite everything, but I have to say it would be much less painful.

Logical code is easy to follow and easy to change. If something is a little strange, then you fall back on the documentation to figure out why. But when the code is an absolute pile of garbage with no documentation, looking like it was written by a first-time coding high schooler, you spend most of your time trying to figure out why the previous author did what they did, how they did it, and why they were ever allowed to touch a computer keyboard in the first place.

 


The problem increases exponentially when dealing with web projects, especially ones coded in PHP. Modular design in web projects has always been possible but somewhat awkward, considering that up until PHP 5 we had very poor object support. Only in the last few years have there been any decent frameworks to use that employ an MVC structure. My favourite one, of course, is Zend Framework. Before the Zend Framework, I personally had been working on an MVC-like PHP framework of my own to help alleviate the somewhat cumbersome structure that even my PHP projects were sometimes taking. After trying the Zend Framework, I never touched my own framework again.

Having come to realize the power of a good PHP framework and the importance of documentation and modularized code, it just makes me want to cry–and wish horrible things upon the original author whose code is making my job so much more difficult than it should be.

Share

Zend Framework

Zend FrameworkI love the Zend Framework. I’ve been using it since version 1.5 (currently at 1.10 as of this writing). It has so many features and can do so many things–sometimes it’s just not immediately clear how to implement those great features.

One feature that took me awhile to figure out was AJAX context switching. The documentation contains various pieces of information about implementing AJAX, but it just wasn’t clear how to put those pieces together. To help make this more clear, I’m going to go through a simple example of how to add very basic AJAX to the Zend Framework QuickStart project. I’m going to be using jQuery because I prefer that to Dojo and the rest of the JavaScript frameworks.

This tutorial assumes you already have a development server set up, Zend Framework installed, and the Zend Framework QuickStart project up and running.

Modify IndexController.php

First we need to set up Ajax context switching in the main controller. Add the following init() function to the index controller found in controllers/IndexController.php

public function init()
{
    $ajaxContext = $this->_helper->getHelper('AjaxContext');
    $ajaxContext->addActionContext('list', 'html')
                ->addActionContext('modify', 'html')
                ->initContext();
}

The html parameter is the type of Ajax request. You can also use JSON or XML.

Note: The modify context is not used in this tutorial but is merely there to demonstrate that you can have as many action contexts as you want.

Now we need to add the list action that we specified above in the addActionContext call to the IndexController.php.

public function listAction() {
    // pretend this is a sophisticated database query
    $data = array('red','green','blue','yellow');
    $this->view->data = $data;
}

Create the list view scripts

By default, Zend Framework tries to render view scripts with the same name as the action. If our action’s name is list and is controlled by the controller named index, then Zend will try to render a view script located at view/scripts/index/list.phtml. Since we are using Ajax context switching, Zend Framework attempts to render view/scripts/index/list.ajax.phtml instead.

For testing my Ajax actions I usually create a normal view helper as well as the Ajax helper but then just include the Ajax view helper.

Create the following view scripts. The second script list.phtml is optional but might aid in troubleshooting.

views/scripts/index/list.ajax.phtml


    data as $color) : ?>

views/scripts/index/list.phtml






jQuery time

The last thing we need to do is to add some HTML and JavaScript to our index.phtml view script to test everything out.

Add the following to the bottom of views/scripts/index/index.phtml

The most important part of that jQuery code is the content of the URL you specify. This is one of those cases when you need to specify the module and controller and action even if they are set to the default value.

‘/module/controller/action/format/html’

You must also not forget the format/html part. If you forget it, you’ll notice that Zend is rendering your layout too instead of just rendering the view script.

That’s it. You should now have a list of colours on the first page of your site.

UPDATE: there was an error in the jQuery code on the index.phtml view script. The code is correct now. I have also added a working project to my Google Code repository. Thanks to the commenters for pointing this out.

Share