wpstream / includes / class-wpstream-seo.php

class-wpstream-seo.php in WpStream – Live Streaming, Video on Demand, Pay Per View 4.14.1, at includes/class-wpstream-seo.php

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1	<?php
2	/**
3	* Front-end SEO metadata for WpStream content.
4	*
5	* Emits the share and discovery markup for the three WpStream singular views —
6	* WooCommerce products, free live channels and free VOD:
7	*
8	* - Open Graph + Twitter card tags, so shared links render a rich preview.
9	* - JSON-LD structured data, so search engines understand the page as video
10	* rather than as a generic article.
11	*
12	* The guiding rule is to enrich, never duplicate. Whatever another component
13	* already states correctly is left alone:
14	*
15	* - rel=canonical belongs to WordPress core, which emits one on every
16	* singular view; a second would be an SEO defect.
17	* - Open Graph and Twitter tags belong to a dedicated SEO plugin (Yoast,
18	* Rank Math) whenever one is active.
19	* - Product and Offer structured data belongs to WooCommerce, which already
20	* describes every product's price and availability.
21	*
22	* What no other component can state is that a WpStream page is video — a
23	* live broadcast or a recording — so that is this class's contribution, for
24	* free channels and paid stream products alike.
25	*
26	* @package Wpstream
27	*/
28
29	// Block direct file access.
30	if ( ! defined( 'ABSPATH' ) ) {
31	exit;
32	}
33
34	/**
35	* Builds and prints WpStream's front-end SEO metadata.
36	*/
37	class Wpstream_Seo {
38
39	/**
40	* Number of words kept in the generated share description.
41	*
42	* Open Graph consumers truncate long descriptions anyway; trimming here
43	* keeps the head small and avoids dumping an entire post body into a tag.
44	*/
45	const DESCRIPTION_WORDS = 30;
46
47	/**
48	* Register the front-end hooks.
49	*
50	* @return void
51	*/
52	public static function init() {
53	// Build the service and print its markup inside the document head.
54	$seo = new self();
55	add_action( 'wp_head', array( $seo, 'render' ) );
56	}
57
58	/**
59	* Print all SEO metadata for the current request.
60	*
61	* Does nothing unless the request is one of the WpStream singular views.
62	*
63	* @return void
64	*/
65	public function render() {
66	// Resolve the post being viewed, or bail on any other kind of request.
67	$post = $this->current_post();
68	if ( null === $post ) {
69	return;
70	}
71
72	// Only claim the social surface when no SEO plugin already owns it.
73	if ( ! $this->seo_plugin_active() ) {
74	$this->render_open_graph( $post );
75	}
76
77	// Structured data is always ours: no general-purpose SEO plugin knows
78	// how to describe a WpStream channel or VOD as a video object.
79	$this->render_schema( $post );
80	}
81
82	/**
83	* Print the JSON-LD structured data block for a post.
84	*
85	* @param WP_Post $post The post being viewed.
86	* @return void
87	*/
88	private function render_schema( $post ) {
89	/**
90	* Filter the structured data emitted for a WpStream singular view.
91	*
92	* Returning an empty array suppresses the block entirely.
93	*
94	* @param array $schema The JSON-LD structure about to be printed.
95	* @param WP_Post $post The post being described.
96	*/
97	$schema = apply_filters( 'wpstream_seo_schema', $this->build_schema( $post ), $post );
98
99	// Nothing to say about this post.
100	if ( empty( $schema ) ) {
101	return;
102	}
103
104	// JSON_HEX_TAG is what makes this block safe to inline: it encodes the
105	// angle brackets as unicode escapes, so post content carrying a closing
106	// script tag cannot terminate the element. JSON_HEX_AMP does the same
107	// for ampersands; JSON_UNESCAPED_SLASHES just keeps the URLs readable.
108	printf(
109	'<script type="application/ld+json">%s</script>' . "\n",
110	wp_json_encode( $schema, JSON_UNESCAPED_SLASHES \| JSON_HEX_TAG \| JSON_HEX_AMP )
111	);
112	}
113
114	/**
115	* Build the schema.org structure describing a post.
116	*
117	* Live channels and VOD are both VideoObjects; a live channel is set apart
118	* by a BroadcastEvent publication, which is the shape search engines look
119	* for when surfacing a livestream.
120	*
121	* @param WP_Post $post The post being described.
122	* @return array The JSON-LD structure, or an empty array when not applicable.
123	*/
124	private function build_schema( $post ) {
125	// Live, recorded, or not WpStream media at all.
126	$kind = $this->media_kind( $post );
127	if ( '' === $kind ) {
128	return array();
129	}
130
131	// Base video description shared by live channels and recordings.
132	$schema = array(
133	'@context' => 'https://schema.org',
134	'@type' => 'VideoObject',
135	'name' => get_the_title( $post ),
136	'description' => $this->description( $post ),
137	'url' => get_permalink( $post ),
138	// Search engines expect an ISO-8601 date here.
139	'uploadDate' => get_post_time( 'c', true, $post ),
140	);
141
142	// Only advertise a thumbnail when the post actually has one.
143	$image = $this->image_url( $post );
144	if ( '' !== $image ) {
145	$schema['thumbnailUrl'] = $image;
146	}
147
148	// A live channel is a broadcast rather than a recording, which is what
149	// search engines look for when surfacing a livestream.
150	if ( 'live' === $kind ) {
151	$schema['publication'] = array(
152	'@type' => 'BroadcastEvent',
153	'isLiveBroadcast' => true,
154	'startDate' => get_post_time( 'c', true, $post ),
155	);
156	}
157
158	return $schema;
159	}
160
161	/**
162	* Classify a post as live streaming, recorded video, or neither.
163	*
164	* Free content is identified by its post type; paid content is an ordinary
165	* WooCommerce product whose product type carries the distinction.
166	*
167	* @param WP_Post $post The post being described.
168	* @return string 'live', 'vod', or an empty string when the post is not
169	* WpStream media.
170	*/
171	private function media_kind( $post ) {
172	// Free live channels and free recordings each have their own post type.
173	if ( 'wpstream_product' === $post->post_type ) {
174	return 'live';
175	}
176	if ( 'wpstream_product_vod' === $post->post_type ) {
177	return 'vod';
178	}
179
180	// Anything else can only qualify as a paid WooCommerce stream.
181	if ( 'product' !== $post->post_type \|\| ! function_exists( 'wc_get_product' ) ) {
182	return '';
183	}
184
185	$product = wc_get_product( $post->ID );
186	if ( ! $product ) {
187	return '';
188	}
189
190	// The plugin's two custom product types mirror the free post types.
191	if ( 'live_stream' === $product->get_type() ) {
192	return 'live';
193	}
194	if ( 'video_on_demand' === $product->get_type() ) {
195	return 'vod';
196	}
197
198	// An ordinary shop product is not video and gets nothing from us.
199	return '';
200	}
201
202	/**
203	* Resolve the post for a WpStream singular view.
204	*
205	* @return WP_Post\|null The current post, or null when this is not a
206	* WpStream singular view.
207	*/
208	private function current_post() {
209	// The share markup applies to paid products and to free live/VOD posts.
210	if ( ! is_singular( array( 'product', 'wpstream_product', 'wpstream_product_vod' ) ) ) {
211	return null;
212	}
213
214	// Read the post from the main query rather than the $post global, so a
215	// stray setup_postdata() elsewhere cannot redirect the tags.
216	$post = get_queried_object();
217
218	// Guard against the queried object being a term or user.
219	return ( $post instanceof WP_Post ) ? $post : null;
220	}
221
222	/**
223	* Detect an active SEO plugin that already emits social metadata.
224	*
225	* @return bool True when Yoast SEO or Rank Math is active.
226	*/
227	private function seo_plugin_active() {
228	// Yoast defines its version constant once loaded; Rank Math its class.
229	return defined( 'WPSEO_VERSION' ) \|\| class_exists( 'RankMath' );
230	}
231
232	/**
233	* Print the Open Graph and Twitter card tags for a post.
234	*
235	* @param WP_Post $post The post being viewed.
236	* @return void
237	*/
238	private function render_open_graph( $post ) {
239	// Full-size featured image URL, or an empty string when none is set.
240	$image = $this->image_url( $post );
241
242	// A Woo product is a purchasable product; live channels and VOD are video.
243	$type = ( 'product' === $post->post_type ) ? 'product' : 'video.other';
244
245	// Without a picture there is nothing for the large card layout to show.
246	$card = ( '' !== $image ) ? 'summary_large_image' : 'summary';
247
248	// Every value is attribute-escaped: stripping tags from post content
249	// leaves quotes intact, which would otherwise close the content
250	// attribute and let the body inject its own markup.
251	printf(
252	'<meta property="og:title" content="%s" />' . "\n",
253	esc_attr( get_the_title( $post ) )
254	);
255	printf(
256	'<meta property="og:url" content="%s" />' . "\n",
257	esc_url( get_permalink( $post ) )
258	);
259	printf(
260	'<meta property="og:type" content="%s" />' . "\n",
261	esc_attr( $type )
262	);
263	printf(
264	'<meta property="og:site_name" content="%s" />' . "\n",
265	esc_attr( get_bloginfo( 'name' ) )
266	);
267	printf(
268	'<meta property="og:description" content="%s" />' . "\n",
269	esc_attr( $this->description( $post ) )
270	);
271
272	// Both image tags are only meaningful when a featured image exists.
273	if ( '' !== $image ) {
274	printf(
275	'<meta property="og:image" content="%s" />' . "\n",
276	esc_url( $image )
277	);
278	printf(
279	'<meta property="og:image:secure_url" content="%s" />' . "\n",
280	esc_url( $image )
281	);
282	}
283
284	// Twitter reads title, description and picture from the og:* tags above;
285	// the card type is the only value with no Open Graph equivalent.
286	printf(
287	'<meta name="twitter:card" content="%s" />' . "\n",
288	esc_attr( $card )
289	);
290	}
291
292	/**
293	* Build the plain-text share description for a post.
294	*
295	* @param WP_Post $post The post being viewed.
296	* @return string Tag-free, trimmed description text.
297	*/
298	private function description( $post ) {
299	// Strip markup first, then shorten to a share-sized summary.
300	return wp_trim_words( wp_strip_all_tags( $post->post_content ), self::DESCRIPTION_WORDS );
301	}
302
303	/**
304	* Resolve the full-size featured image URL for a post.
305	*
306	* @param WP_Post $post The post being viewed.
307	* @return string Image URL, or an empty string when no featured image is set.
308	*/
309	private function image_url( $post ) {
310	// Featured image attachment id, 0 when the post has none.
311	$image_id = get_post_thumbnail_id( $post );
312	if ( ! $image_id ) {
313	return '';
314	}
315
316	// wp_get_attachment_image_src() returns [url, width, height, is_resized].
317	$src = wp_get_attachment_image_src( $image_id, 'full' );
318
319	return ( is_array( $src ) && ! empty( $src[0] ) ) ? $src[0] : '';
320	}
321	}
322
323	// Wire the front-end hooks as soon as this file is loaded.
324	Wpstream_Seo::init();
325