Filter WP Basic HTTP Authentication Credentials

filter-wp-basic-http-authentication-credentials.php

<?php
/**
 * Plugin Name: Filter WP Basic HTTP Authentication Credentials
 * Description: Filter WP Basic HTTP Authentication Credentials to use environment variables
 * Author: James Morrison
 * Version: 1.0.0
 * Author URI: https://www.jamesmorrison.me
 **/

// Filter the credentials
add_filter( 'wp_basic_auth_credentials',
	function( $credentials ) {

		// Ensure the expected server variable is available
		if ( ! isset( $_SERVER['http_authentication_credentials'] ) ) {
			return $credentials;
		}

		// $credentials should be an array, just in case it isn't, validate and create one if need be
		if ( ! is_array( $credentials ) ) {
			$credentials = [];
		}

		// Remove the example user
		// This is a key => value based array so we can simply unset the array key
		unset( $credentials['example_user'] );

		// Load credentials from the environment variable
		// Expected format is:
		// user_1:password_1,user_2:password_2
		$environment_credentials = sanitize_text_field( $_SERVER['http_authentication_credentials'] );

		// Break the string to an array of individual sets of usernames and passwords
		$credentials_array = explode( ',', $environment_credentials );

		// Loop through each set of credentials
		foreach ( $credentials_array as $username_password ) {

			// Break the user_1:password_1 to an array
			$username_password_array = explode( ':', $username_password );

			// Add the username and password to the $credentials array
			$credentials[ $username_password_array[0] ] = $username_password_array[1];

		}

		// Send back our credentials
		return $credentials;

	}, 1, 1
);