om4-header-footer-code.php

<?php
/*
Plugin Name: OM4 Header/Footer Code
Plugin URI: https://github.com/OM4/om4-header-footer-code
Description: Use the WordPress dashboard to add custom HTML code to the head section or closing body section. Also ensures jQuery is always available in the frontend.
Version: 1.1.1
Author: OM4
Author URI: https://github.com/OM4/
Text Domain: om4-header-footer-code
Git URI: https://github.com/OM4/om4-header-footer-code
Git Branch: release
License: GPLv2
*/

/*
	Copyright 2012-2024 OM4 (email: plugins@om4.com.au    web: http://om4.com.au/)

	This program is free software; you can redistribute it and/or modify
	it under the terms of the GNU General Public License as published by
	the Free Software Foundation; either version 2 of the License, or
	(at your option) any later version.

	This program is distributed in the hope that it will be useful,
	but WITHOUT ANY WARRANTY; without even the implied warranty of
	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
	GNU General Public License for more details.

	You should have received a copy of the GNU General Public License
	along with this program; if not, write to the Free Software
	Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
*/


if ( ! class_exists( 'OM4_Plugin_Appearance' ) ) {
	require_once 'includes/OM4_Plugin_Appearance.php';
}


/**
 * Custom Header/Footer Code implementation:
 * - Adds Dashboard -> Appearance -> Header & Footer screen, which is accessible to any WordPress Administrator with the unfiltered_html capability.
 *
 * Should work with OM4 Theme, any WooTheme, and (hopefully) any other WordPress theme.
 */
class OM4_Header_Footer extends OM4_Plugin_Appearance {

	public function __construct() {

		$this->screen_title = 'Header & Footer Code';
		$this->screen_name  = 'headerfooter';

		if ( is_admin() ) {
			add_action( 'admin_post_update_header_footer_code', array( $this, 'dashboard_screen_save' ) );
		}

		add_action( 'wp_enqueue_scripts', array( $this, 'wp_enqueue_scripts' ) );

		add_action( 'wp_head', array( $this, 'maybe_display_header_code' ), $this->get_header_code_priority() );
		add_action( 'wp_footer', array( $this, 'maybe_display_footer_code' ), 9999999 );
		// Big number so it is right before the </body> tag.

		parent::__construct();
	}

	/**
	 * Always include jQuery in the frontend
	 */
	public function wp_enqueue_scripts(): void {
		wp_enqueue_script( 'jquery' );
	}

	/**
	 * Get the URL to this plugin's folder
	 */
	public function plugin_url(): string {
		return untrailingslashit( plugins_url( '/', __FILE__ ) );
	}

	/**
	 * Determine whether the currently logged in user has access to the custom header/footer script fields.
	 *
	 * This is defined as anyone who has access the manage_options and the unfiltered_html capabilities. In other words:
	 * - for Standalone Sites, any Administrator users
	 * - for Multisite, any Administrator user who (is a super admin or has a KSES Exemption configured via Network Admin -> Settings -> KSES Exemptions )
	 *
	 * @return bool
	 */
	public function can_manage_code(): bool {
		return $this->can_access_dashboard_screen() && current_user_can( 'unfiltered_html' );
	}

	public function get_header_code(): string {
		return strval( get_option( 'om4_custom_header_code', '' ) );
	}

	public function set_header_code( string $code ): bool {
		return update_option( 'om4_custom_header_code', $code );
	}

	public function get_header_code_priority(): int {
		return intval( get_option( 'om4_custom_header_code_priority', 10 ) );
	}

	public function set_header_code_priority( string $priority ): bool {
		return update_option( 'om4_custom_header_code_priority', intval( $priority ) );
	}

	public function maybe_display_header_code(): void {
			$text = $this->get_header_code();
		if ( $text ) {
			$text = do_shortcode( $text );
			echo "\n$text\n";
		}
	}

	public function get_footer_code(): string {
		return strval( get_option( 'om4_custom_footer_code', '' ) );
	}

	public function set_footer_code( string $code ): bool {
		return update_option( 'om4_custom_footer_code', $code );
	}

	public function maybe_display_footer_code(): void {
			$text = $this->get_footer_code();
		if ( $text ) {
			$text = do_shortcode( $text );
			echo "\n$text\n";
		}
	}

	public function dashboard_screen(): void {
		?>
		<div class='wrap'>
			<div id="om4-header">
				<h2>Header and Footer Code/Script</h2>
				<?php
				if ( ! $this->can_manage_code() ) {
					echo '<div class="error"><p>You do not have permission to access this feature.</p></div></div></div>';
					return;
				}

				if ( isset( $_GET['updated'] ) ) {
					echo '<div id="message" class="updated"><p>Header/Footer Code saved.</p></div>';
				}

				?>
				<form action="<?php echo $this->form_action(); ?>" method="post">
				<h4>Custom Header Code/Script</h4>
				<p>This can be used to add any custom HTML inside the <code>&lt;head&gt;</code> section of every page. For example, an external JavaScript file can be referenced here using a <code>&lt;script&gt;</code> tag.</p>
				<?php

				wp_editor( $this->get_header_code(), 'headercode', $this->wp_editor_defaults );
				?>
				<h4>Custom Header Code/Script Priority</h4>
				<p>The priority below lets you specify where in the <code>&lt;head&gt;</code> section the <em>Custom Header Code/Script</em> will be output.<br />
							A small number will cause the code to be output closer to the opening <code>&lt;head&gt;</code> tag, whereas a large number will cause the code to be output closer to the closing <code>&lt;/head&gt;</code> tag.</p>

				<p>
					<label for="header_code_priority">Custom Header Code/Script Priority:</label>
					<input name="header_code_priority" type="text" id="header_code_priority" value="<?php echo esc_attr( (string) $this->get_header_code_priority() ); ?>" />
				</p>
				<h4>Custom Footer Code/Script</h4>
						<p>This can be used to add any custom HTML just before the <code>&lt;/body&gt;</code> tag of every page. For example, an external JavaScript file can be referenced here using a <code>&lt;script&gt;</code> tag.</p>
				<?php
				wp_editor( $this->get_footer_code(), 'footercode', $this->wp_editor_defaults );
				?>
				<input type="hidden" name="action" value="update_header_footer_code" />
				<?php
				wp_nonce_field( 'update_header_footer_code' );
				?>
				<p class="submit"><input type="submit" name="submit" id="submit" class="button-primary" value="Save Changes"></p>
				</form>
			</div>
			<script src="<?php echo esc_attr( $this->plugin_url() ); ?>/CodeMirror/lib/codemirror.js?v=5.65.16"></script>
			<link rel="stylesheet" href="<?php echo esc_attr( $this->plugin_url() ); ?>/CodeMirror/lib/codemirror.css?v=5.65.16">
			<style type="text/css">
				.CodeMirror {
					height: auto;
				}
			</style>
			<script>
				var headerCodeMirror = CodeMirror.fromTextArea(document.getElementById('headercode'), {
					lineNumbers: true, // Show line numbers
					mode: "text/html", // HTML mode
					viewportMargin: Infinity, // Expand the editor to the height of the code
					lineWrapping: true, // Line Wrapping
					matchBrackets: true, // Highlight matching brackets
					autofocus: true, // Autofocus the cursor into the editor on page load
				});
				var headerCodeMirror = CodeMirror.fromTextArea(document.getElementById('footercode'), {
					lineNumbers: true, // Show line numbers
					mode: "text/html", // HTML mode
					viewportMargin: Infinity, // Expand the editor to the height of the code
					lineWrapping: true, // Line Wrapping
					matchBrackets: true // Highlight matching brackets
				});
			</script>
		</div>
		<?php
	}

	/**
	 * Handler that saves the dashboard screen's options/values, then redirects back to the Dashboard Screen
	 */
	public function dashboard_screen_save(): void {

		$url = $this->dashboard_url();

		if ( $this->can_manage_code() ) {

			check_admin_referer( 'update_header_footer_code' );

			// @phpcs:ignore WordPress.Security.ValidatedSanitizedInput.InputNotSanitized
			$this->set_header_code( isset( $_POST['headercode'] ) ? wp_unslash( $_POST['headercode'] ) : '' );

			// @phpcs:ignore WordPress.Security.ValidatedSanitizedInput.InputNotSanitized
			$this->set_header_code_priority( isset( $_POST['header_code_priority'] ) ? wp_unslash( $_POST['header_code_priority'] ) : 10 );

			// @phpcs:ignore WordPress.Security.ValidatedSanitizedInput.InputNotSanitized
			$this->set_footer_code( isset( $_POST['footercode'] ) ? wp_unslash( $_POST['footercode'] ) : '' );

			// Allow other plugins to perform actions whenever the header/footer code is saved.
			do_action( 'om4_header_footer_code_saved' );

			$url = $this->dashboard_url_saved();

		}

		wp_safe_redirect( esc_url_raw( $url ) );
		exit;
	}
}


global $om4_header_footer;
$om4_header_footer = new OM4_Header_Footer();

/** BEGIN GLOBAL FUNCTIONS - these are used outside of this plugin file **/
function om4_get_custom_header_code(): string {
	global $om4_header_footer;
	return $om4_header_footer->get_header_code();
}

function om4_get_custom_footer_code(): string {
	global $om4_header_footer;
	return $om4_header_footer->get_footer_code();
}

function om4_can_edit_custom_script_code(): bool {
	global $om4_header_footer;
	return $om4_header_footer->can_manage_code();
}

/** END GLOBAL FUNCTIONS */