Jacob Santos

Patterns for PHP Contribution

I’ve decided it would have been a mockery to PHP developers, if I had taken up writing about MVC, which I still barely know anything about. However, I have been working a little bit with Page Controller Pattern of MVC. I decided I could write what little I do know and let someone with more knowledge fill in the blanks. Helping myself and others in the community.

Types of Page Controllers

From my experience, it seems Page Controlling falls into three categories, based on difficultly of implementation.

1. IF Block Structure
2. Directory Structure
3. Object Method

If Block

When I first seen this in Dragon Knight, I laughed like a fool. At the time, I was coding using multiple pages with no mod_rewrite. Nothing wrong with using multiple pages, however I noticed some security problems with the Dragon Knights method, which were fixed.

The structure is as follows:

if($page == 'page_name') {

    // Do and include stuff

} else if($page == 'page_name') {

    // Do and include stuff

} else if($page == 'another_page_name') {

    // Do and include stuff

}

Really easy to do and the most basic representation of a Page Controller pattern. The Page variable can be from a $_GET key or from the url path function.

This method has flaws: for one, if there are many pages that need to be controlled, then the if block can get fairly large and hard to manage; and two, once it does get large, say around 1000 to 100000 blocks, it can be slow.

Directory Structure

This method has been bouncing around in my mind every since I read and heard the podcast about “PHP Best Practices” and for the life of me, I can’t remember where the blog and podcast is. I didn’t laugh, but I just thought that without any more information, such as PHP code, the podcast was pretty worthless. The statement was only having one index.php file that included all of the required files, adding some security and ease of development. It was interesting, but I didn’t “grok” it until several days ago when I was thinking about how to best maintain the Gamehole Page Controller.

Note: I haven’t developed any code, but I do have some sort of pseudo-code for how to go about the method.

// Get the path names for inclusion
$pathList = explode('/', $_SERVER['QUERY_STRING']);

// Find the amount of levels for directory and file inclusion.
$pathDepth = count($pathList);

define("PROJECT_PATH", realpath(dirname(__FILE__).'/../project'));

if($pathDepth == 0) {
     require PROJECT_PATH.'/controller/default.php';
} else {
    $path = PROJECT_PATH;
    foreach($pathList as $pathElement)
    {
        $file = $path.'/'.$pathElement;

        if($pathDepth == 1) {
            if(is_file($file)) {
                include($file);
            } else {
                if(is_file($file.'/default.php')) {
                    include($file.'/default.php');
                } else {
                    header("Status: 404 Not Found");
                }
            }
        } else {
            if(!is_dir($file)) {
                header("Status: 404 Not Found");
            }
        }

        $pathDepth--;    // Is Directory; Maybe
    }
}

The amount of lines is still less than Gamehole, even with the checks. Without any debugging this probably won’t work “out of box”. As a prototype, it is meant to collect the directory structure from the URL and finally the file, then include it after checking that it exists.

The advantage is that I wouldn’t have to touch the page controller at all to add new pages to the list. It also has less chance that I’ll forget a bracket and the whole PHP site would fail. Removing a single point of site failure is a problem that I needed to address with future development.

Object Method

Many frameworks and classes exist for handling the Page Controller using an object.

This is where my “tutorial” ends. I have not yet developed with this method, so I know nothing how it works. I do hope to learn after working with the second method for a while.

Update:

The page controller I was looking for was Cgiapp2.

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