Developing PHP programs whose main task is to dynamically include files required by a specific application isn’t as difficult as it may seem at first sight. In these cases, the logic that drives those programs is implemented around the set of “include()/include_once()/require()/require_once()” native PHP functions, which are pretty familiar to many developers having an average background on this language.

So, if you’re searching for an approachable guide that shows you how to build file loading applications in PHP 5, without having to pull your hair desperately, then hopefully this group of articles will give you the material you're looking for.  

By this time, you’re well aware of the goal of this article series, so I’d like to spend a few moments refreshing the concepts I explained in the previous part. In that article, I developed a basic loader class which was capable of including a specified file without having to create any instances of the class. This capacity was implemented by defining a static loading method, which was in reality the class’s workhorse, since it acted like a wrapper for the “require_once()” PHP function. 

While this file loading class in its current incarnation does a pretty good job, it lacks an important feature that could be added with relative ease. It cannot perform a recursive search through the web server’s file system, and afterward include a specified file within a given application. 

Essentially, the class would be passed a starting path to look for, and from that point onward it would recursively traverse the subfolders, until finding the targeted file. That’s an ability found in many popular PHP applications available nowadays, and in the next few lines I’m going to explain how to implement it, based mostly on the structure of the loader class created in previous chapter of the series. 

Now, let’s start learning how to build a loading class that will have recursive file searching capabilities. Let’s get going!