desktop-mode / includes / about-feed.php

about-feed.php in OpenStation: Desktop Windows, Dock & Virtual Desktops for WP Admin 1.1.9, at includes/about-feed.php

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1	<?php
2	/**
3	* OpenStation — About-tab journal feed.
4	*
5	* Fetches the public OpenStation RSS feed on demand, normalizes it to
6	* plain-text card data, and serves it through an authenticated admin-AJAX
7	* request. Keeping the request lazy means opening the shell never waits on
8	* the remote blog; the network is touched only when someone visits About.
9	*
10	* @package OpenStation
11	*/
12
13	defined( 'ABSPATH' ) \|\| exit;
14
15	const OPENSTATION_ABOUT_FEED_URL = 'https://openstation.blog/feed/';
16	const OPENSTATION_ABOUT_SITE_URL = 'https://openstation.blog/';
17	const OPENSTATION_ABOUT_FEED_CACHE_KEY = 'desktop_mode_about_feed_v1';
18	const OPENSTATION_ABOUT_FEED_STALE_KEY = 'desktop_mode_about_feed_stale_v1';
19	const OPENSTATION_ABOUT_FEED_FAILURE_KEY = 'desktop_mode_about_feed_failure_v1';
20
21	/**
22	* Give this one feed a shorter cache than WordPress' default 12 hours.
23	*
24	* The callback is installed only around our own `fetch_feed()` call and
25	* removed immediately afterwards, so dashboard RSS widgets keep their own
26	* cache policy.
27	*
28	* @param int $seconds Existing cache lifetime.
29	* @param string $url Feed URL.
30	* @return int Cache lifetime in seconds.
31	*/
32	function openstation_about_feed_cache_lifetime( $seconds, $url ) {
33	return OPENSTATION_ABOUT_FEED_URL === $url ? 30 * MINUTE_IN_SECONDS : $seconds;
34	}
35
36	/**
37	* Bound the cold-feed request so an unavailable journal cannot pin the tab.
38	*
39	* @param SimplePie $feed Feed parser instance.
40	* @param string $url Feed URL.
41	*/
42	function openstation_about_feed_options( $feed, $url ) {
43	if ( OPENSTATION_ABOUT_FEED_URL === $url && is_callable( array( $feed, 'set_timeout' ) ) ) {
44	$feed->set_timeout( 5 );
45	}
46	}
47
48	/**
49	* Collapse remote feed text to one safe, readable line.
50	*
51	* @param mixed $value Remote feed value.
52	* @return string Plain text.
53	*/
54	function openstation_about_feed_text( $value ) {
55	$text = html_entity_decode(
56	wp_strip_all_tags( (string) $value, true ),
57	ENT_QUOTES \| ENT_HTML5,
58	'UTF-8'
59	);
60	$text = preg_replace( '/\s+/u', ' ', $text );
61	return sanitize_text_field( trim( (string) $text ) );
62	}
63
64	/**
65	* Convert a parsed SimplePie feed into the small JSON shape the About tab uses.
66	*
67	* No remote HTML crosses the boundary: titles, author names and excerpts are
68	* flattened to text, URLs pass through WordPress' URL sanitizer, and the list
69	* is capped before it reaches the browser.
70	*
71	* @param SimplePie $feed Parsed feed instance.
72	* @return array Normalized feed payload.
73	*/
74	function openstation_normalize_about_feed( $feed ) {
75	$items = array();
76	$feed_items = $feed->get_items( 0, 5 );
77
78	foreach ( $feed_items as $item ) {
79	$title = openstation_about_feed_text( $item->get_title() );
80	$url = esc_url_raw( (string) $item->get_permalink() );
81	if ( '' === $title \|\| '' === $url ) {
82	continue;
83	}
84
85	$author = $item->get_author();
86	$author_name = $author ? openstation_about_feed_text( $author->get_name() ) : '';
87	$excerpt = openstation_about_feed_text( $item->get_description() );
88
89	$items[] = array(
90	'title' => $title,
91	'url' => $url,
92	'author' => $author_name,
93	'publishedAt' => sanitize_text_field( (string) $item->get_date( 'c' ) ),
94	'excerpt' => wp_trim_words( $excerpt, 36, '…' ),
95	);
96	}
97
98	$title = openstation_about_feed_text( $feed->get_title() );
99	$description = openstation_about_feed_text( $feed->get_description() );
100	$home_url = esc_url_raw( (string) $feed->get_link() );
101
102	return array(
103	'title' => '' !== $title ? $title : 'OpenStation',
104	'description' => '' !== $description
105	? $description
106	: 'A public dev diary — building a desktop OS for wp-admin.',
107	'homeUrl' => '' !== $home_url ? $home_url : OPENSTATION_ABOUT_SITE_URL,
108	'feedUrl' => OPENSTATION_ABOUT_FEED_URL,
109	'items' => $items,
110	'stale' => false,
111	);
112	}
113
114	/**
115	* Return the cached journal payload, fetching RSS only when the cache is cold.
116	*
117	* A last-known-good copy survives for a week. If the blog has a temporary
118	* outage, the About tab can still show useful posts and quietly mark the data
119	* stale instead of replacing the whole page with an error.
120	*
121	* @return array\|WP_Error Feed payload or a private fetch error.
122	*/
123	function openstation_get_about_feed() {
124	$cached = get_transient( OPENSTATION_ABOUT_FEED_CACHE_KEY );
125	if ( is_array( $cached ) ) {
126	return $cached;
127	}
128
129	$stale = get_transient( OPENSTATION_ABOUT_FEED_STALE_KEY );
130	if ( false !== get_transient( OPENSTATION_ABOUT_FEED_FAILURE_KEY ) ) {
131	if ( is_array( $stale ) ) {
132	$stale['stale'] = true;
133	return $stale;
134	}
135	return new WP_Error( 'openstation_about_feed_unavailable' );
136	}
137
138	require_once ABSPATH . WPINC . '/feed.php';
139	add_filter( 'wp_feed_cache_transient_lifetime', 'openstation_about_feed_cache_lifetime', 10, 2 );
140	add_action( 'wp_feed_options', 'openstation_about_feed_options', 10, 2 );
141	$feed = fetch_feed( OPENSTATION_ABOUT_FEED_URL );
142	remove_filter( 'wp_feed_cache_transient_lifetime', 'openstation_about_feed_cache_lifetime', 10 );
143	remove_action( 'wp_feed_options', 'openstation_about_feed_options', 10 );
144
145	if ( is_wp_error( $feed ) ) {
146	set_transient( OPENSTATION_ABOUT_FEED_FAILURE_KEY, '1', 5 * MINUTE_IN_SECONDS );
147	if ( is_array( $stale ) ) {
148	$stale['stale'] = true;
149	return $stale;
150	}
151	return new WP_Error( 'openstation_about_feed_unavailable' );
152	}
153
154	$payload = openstation_normalize_about_feed( $feed );
155	set_transient( OPENSTATION_ABOUT_FEED_CACHE_KEY, $payload, 30 * MINUTE_IN_SECONDS );
156	set_transient( OPENSTATION_ABOUT_FEED_STALE_KEY, $payload, WEEK_IN_SECONDS );
157	delete_transient( OPENSTATION_ABOUT_FEED_FAILURE_KEY );
158	return $payload;
159	}
160
161	/**
162	* Serve the latest OpenStation journal posts to the current shell user.
163	*/
164	function openstation_ajax_about_feed() {
165	check_ajax_referer( 'openstation_about_feed', 'nonce' );
166
167	if ( ! current_user_can( 'read' ) \|\| ! openstation_is_enabled() ) {
168	wp_send_json_error(
169	array( 'message' => __( 'You cannot load OpenStation updates.', 'desktop-mode' ) ),
170	403
171	);
172	}
173
174	$feed = openstation_get_about_feed();
175	if ( is_wp_error( $feed ) ) {
176	wp_send_json_error(
177	array( 'message' => __( 'The OpenStation journal is temporarily unavailable.', 'desktop-mode' ) ),
178	502
179	);
180	}
181
182	wp_send_json_success( $feed );
183	}
184	add_action( 'wp_ajax_openstation_about_feed', 'openstation_ajax_about_feed' );
185