A Guide to WordPress PHP

WordPress php

Looking to understand WordPress PHP? In this post, we’ll unpack what PHP is and how it works with WordPress. Understanding PHP and how it integrates with WordPress will help with site maintenance, troubleshooting errors and WordPress development in general.

What is PHP?

PHP, an abbreviation for Hypertext Preprocessor, is a scripting language used by approximately 79% of the web. PHP allows you to do many powerful things, such as interacting with a database, writing conditional statements, obtain WordPress-specific information, pull in media files and much more.

WordPress PHP

PHP is what powers WordPress, as most of the WordPress core files are written in this language. If you look at the file listing of a WordPress website, you’ll see that most files end in .php, meaning the file is PHP file. Most of the WordPress PHP files listed in the screenshot below are necessary for a WordPress website to operate.

How PHP Works: WordPress Websites

Let’s look at a real-world example of how PHP is used on a WordPress website. In this example, we will use a conditional statement to determine whether or not a user is logged in:


<?php
if ( true === user_is_logged_in() ) {   
   echo 'You are logged in!';
} else {
   echo 'You are not logged in! Please sign in.';
}

Even if you have no knowledge of PHP, you can take away that either a user is logged in or not logged in. We use a conditional (if/else) to check if the user is logged in or not, if they are then we will display a message welcoming them and if they are not then we will ask them to sign in. While this is just a basic example, you can see just how powerful conditionals can be.

You can see that we checked the function, “user_is_logged_in”. We know this is a function since it has the parentheses “()” after the name.

If the function returns false, then when the code is run it will display the message:

“You are not logged in! Please sign in.”

PHP and WordPress

Just from the example above, you will notice that PHP is found everywhere in WordPress. WordPress has subsystems like loops that control the number of posts shown, along with hooks that modify functionality, APIs, and themes and plugins.

WordPress PHP: Enable Debugging

WordPress, by default, will not show any errors/warnings that are generated by PHP. This is a good practice for sites that are in production, but if you’re developing then you want this enabled. To enable debugging, simply change this line in the wp-config.php file, which is found in the root directory of WordPress:

define( 'WP_DEBUG', false );

Simply change the constant WP_DEBUG to true, and then save the file. Any errors or warnings hidden will now be displayed,

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This article was written by Tyler Gilbert and originally published on WordPress News and Updates from iThemes – iThemes.

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