Question

I’m working on a project (simple XML CMS) just to learn some basic PHP.

First I include a config.php file which contains information about the CMS, and then I include a route.php for the URL routing and after that I include a functions.php file which is pretty similar to the WordPress’ one (contains all the functions to for example load posts, tags, categories, etc.).

The structure looks like this:

<?php
    function latestProducts($amount = 6){
    }

    function products($search = FALSE, $query= '', $page = 1, $results = 5){
    }

    function getProductById($id){
    }

    function getProductTitleById($id){
    }

    function getProductByExcerpt($excerpt){
    }

    function getProductTitleByExcerpt($excerpt){
    }

    function getPost($id, $title, $description, $category, $excerpt = FALSE){
    }

    function getTitle(){
    }

    function breadcrumb($params, $first){
    }

    function pagination($page, $pages){
    }
?>

In config.php file I also use this code:

$xml = simplexml_load_file("products.xml") or die("The product XML file couldn't be loaded.");

But when I try to access $xml from within the functions I prepared in functions.php, I get a undefined variable notice. (I also tried placing the $xml variable inside the functions.php before the definition of the functions, but I got the same result.)

What is my mistake? I know it’s simple; I just can’t see clearly right now.

Answer 1

You have a scoping issue. The variables declared in the global scope aren’t visible inside your functions. The manual explains what you can do about it. An overview:

• Import the variable from the global scope into the local scope of your function with global $xml; at the start of the function
• Store the variable as a key of the global variables superglobal, i.e. $GLOBALS['xml']
• Make the variable a static member of a class or create a singleton construction
• Pass the variable as an argument to every function that needs it

Note that when using a good OOP-style architecture these kind of problems can often be avoided, e.g. $xml would be a property of class instances that need direct access to the DOM object.