Using a custom class in a Wordpress theme

Question

I have a PHP class with methods that I would like to use anywhere I choose on my theme.
For instance this class:

<?php
class MyClass
{
    const constant = 'constant value';

    function showConstant() {
        echo  self::constant . "\n";
    }
}


$class = new MyClass();
$class->showConstant();

?>

How would I include such a class in my theme?

Answer 1

You have a couple of ways to go about this; you can write a plugin, which might be a bit overkill, but you can also:

1
In your functions.php-file, just add your functions there, and then you can call them in your theme

function myClassFunction() {
  class MyClass {
    const constant = 'constant value';

    function showConstant() {
        echo  self::constant . "\n";
    }
  }

  $class = new MyClass();
  $class->showConstant();
}

2
Create a new directory in your themes folder, something like /includes. Put your class in there. Then wherever in your theme where you need your class and it's functions, just include it in your template:

<?php
  require_once('includes/MyClass.php');
  $class = new MyClass();
  $class->showConstant();
?>

It all depends on what kind of class it is, what it does and how often you use it. There are a whole lot of ways to do it.