google-tag-manager / google-tag-manager.php

google-tag-manager.php in Google Tag Manager trunk, at google-tag-manager.php

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1	<?php
2	/**
3	* Plugin Name: Google Tag Manager
4	* Plugin URI: https://wordpress.org/plugins/google-tag-manager/
5	* Description: This is an implementation of the Tag Management system from Google. It adds a field to the existing General Settings page for the ID, and if specified, outputs the tag management javascript in the page footer.
6	* Version: 1.0.4
7	* Author: George Stephanis
8	* Author URI: https://georgestephanis.wordpress.com
9	* License: GPLv2 or later
10	*
11	* @package Google_Tag_Manager
12	*/
13
14	/**
15	* Main plugin class. Registers settings and outputs GTM snippets.
16	*/
17	class Google_Tag_Manager {
18
19	/**
20	* Whether the noscript tag has already been printed on this page load.
21	*
22	* @var bool
23	*/
24	public static $printed_noscript_tag = false;
25
26	/**
27	* Register all hooks.
28	*
29	* @return void
30	*/
31	public static function go() {
32	add_action( 'admin_init', array( __CLASS__, 'register_fields' ) );
33	add_action( 'wp_head', array( __CLASS__, 'print_tag' ), 1 );
34	add_action( 'wp_body_open', array( __CLASS__, 'print_noscript_tag' ) ); // Core wp_body_open hook added in WP 5.2.
35	add_action( 'genesis_before', array( __CLASS__, 'print_noscript_tag' ) ); // Genesis theme framework.
36	add_action( 'tha_body_top', array( __CLASS__, 'print_noscript_tag' ) ); // Theme Hook Alliance.
37	add_action( 'body_top', array( __CLASS__, 'print_noscript_tag' ) ); // THA unprefixed variant.
38	add_action( 'wp_footer', array( __CLASS__, 'print_noscript_tag' ) ); // Fallback for themes without body-open support.
39	}
40
41	/**
42	* Register the Google Tag Manager ID setting on the General Settings page.
43	*
44	* @return void
45	*/
46	public static function register_fields() {
47	register_setting(
48	'general',
49	'google_tag_manager_id',
50	array(
51	'sanitize_callback' => 'sanitize_text_field',
52	'default' => '',
53	)
54	);
55	add_settings_field( 'google_tag_manager_id', '<label for="google_tag_manager_id">' . esc_html__( 'Google Tag Manager ID', 'google-tag-manager' ) . '</label>', array( __CLASS__, 'fields_html' ), 'general' );
56	}
57
58	/**
59	* Render the Google Tag Manager ID settings field.
60	*
61	* @return void
62	*/
63	public static function fields_html() {
64	?>
65	<input type="text" id="google_tag_manager_id" name="google_tag_manager_id" placeholder="ABC-DEFG" class="regular-text code" value="<?php echo esc_attr( get_option( 'google_tag_manager_id', '' ) ); ?>" />
66	<p class="description"><?php esc_html_e( 'The ID from Google\'s provided code (as emphasized):', 'google-tag-manager' ); ?><br />
67	<code><noscript><iframe src="//www.googletagmanager.com/ns.html?id=<strong style="color:#c00;">ABC-DEFG</strong>"</code></p>
68	<p class="description">
69	<?php
70	printf(
71	wp_kses(
72	/* translators: %s: URL to the Google Tag Manager sign-up page */
73	__( 'You can get yours <a href="%s">here</a>!', 'google-tag-manager' ),
74	array( 'a' => array( 'href' => array() ) )
75	),
76	esc_url( 'https://www.google.com/tagmanager/' )
77	);
78	?>
79	</p>
80	<?php
81	}
82
83	/**
84	* Output the Google Tag Manager JavaScript snippet in the <head>.
85	*
86	* @return void
87	*/
88	public static function print_tag() {
89	$id = get_option( 'google_tag_manager_id', '' );
90	if ( ! $id ) {
91	return;
92	}
93	?>
94	<!-- Google Tag Manager -->
95	<script>(function(w,d,s,l,i){w[l]=w[l]\|\|[];w[l].push({'gtm.start':
96	new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],
97	j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src=
98	'https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);
99	})(window,document,'script','dataLayer','<?php echo esc_js( $id ); ?>');</script>
100	<!-- End Google Tag Manager -->
101	<?php
102	}
103
104	/**
105	* Output the Google Tag Manager noscript iframe immediately after <body>.
106	*
107	* Hooked to several body-open actions to maximise theme compatibility;
108	* a static flag ensures the tag is only printed once regardless of which
109	* hook fires first.
110	*
111	* @return void
112	*/
113	public static function print_noscript_tag() {
114	// Only print the noscript tag once across all the hooks we're trying.
115	if ( self::$printed_noscript_tag ) {
116	return;
117	}
118	self::$printed_noscript_tag = true;
119
120	$id = get_option( 'google_tag_manager_id', '' );
121	if ( ! $id ) {
122	return;
123	}
124	?>
125	<!-- Google Tag Manager (noscript) -->
126	<noscript><iframe src="https://www.googletagmanager.com/ns.html?id=<?php echo esc_attr( $id ); ?>"
127	height="0" width="0" style="display:none;visibility:hidden"></iframe></noscript>
128	<!-- End Google Tag Manager (noscript) -->
129	<?php
130	}
131	}
132
133	Google_Tag_Manager::go();
134