RSS feed cache with redundancy

rss_cache_redudancy.php

<?php

/*
 * RSS Cache
 * Cache: 1 hour
 * Cache fallback: no expiry (not infaillible)
 */

// PROD
$newsURLall = 'https://news.example.com/';
$mynews_url = 'https://news.example.com/rss';

//DEV
//error_log( "News: delete cache.");
//delete_transient('mynews');
//delete_transient('mynews_cache_fallback');

if ( !get_transient( 'mynews' ) ) {
	//error_log( "News: Expired cache.");
	$response =  wp_remote_get($mynews_url);
	if ( !is_array( $response ) && is_wp_error( $response ) ){
		error_log( "News: The news service is not available. ".$response->get_error_message() );
		if ( false === ( get_transient( 'mynews_cache_fallback' ) ) ) {
			if ( current_user_can( 'manage_options' ) ) {// ?>
				<div class="notice notice-error">
				<p><?php _e( "News: The news service is not available." ); ?></p>
				</div><?php
				error_log( "News: The news service is not available, and the redundant cache has expired.  ".$response->get_error_message() );
			}
			return;
		} else {
			//error_log( "News: We have a cache fallback. ".$response->get_error_message() );
			$mynews = get_transient('mynews_cache_fallback' );
		}
	} else {
		//error_log('News: Cache refresh');
		$mynews = $response['body'];
		delete_transient('mynews');
		delete_transient('mynews_cache_fallback');
		set_transient('mynews', $mynews, 1 * HOUR_IN_SECONDS );
		set_transient('mynews_cache_fallback', $mynews );
	}
} else {
	//error_log( "News: Lets use the cache.");
	$mynews = get_transient('mynews_cache_fallback' );
}
?>
<div id="news" class="news_section">
	<h2><?php _e('News', ''); ?></h2>
	<div class="all_links hidden-xs">
		<a href="<?php echo $newURLall; ?>"><?php _e('All news stories', ''); ?></a>
	</div>
	<div class="news" style="clear: both">
		<?php
		$news_json = json_decode($mynews, true);
		if (empty($news_json['data'])){
			echo 'No news.';
		}
		foreach ($news_json['data'] as $news_story) { ?>
			<div class="news__item">
				<div class="news__date"><?php
					$news_sdate = DateTime::createFromFormat('Y-m-d H:i:s', $news_story['next_date']);
					$news_ndate = DateTime::createFromFormat('Y-m-d H:i:s', $news_story['end_date']);
					echo ucfirst( date_i18n( 'l j F', $news_sdate->getTimestamp() ) ); ?></div>
				<div class="news__time clear"><?php
					echo date_format($news_sdate, 'G\hi');
					echo '&nbsp;' . date_format($news_ndate, 'G\hi');
					?></div>
				<a class="news__title" href="<?php echo $news_story['url']; ?>"><?php
					echo $news_story['title'];
					?></a>
			</div>
		<?php } //end foreach
		?>
	</div>

	<div class="clear"></div>
</div><!-- #/news-->