WP_Widget_RSS::widget( array $args, array $instance )

Compatibility

Present in every tracked release (6.7.7 to 7.1.0), and compiles on PHP 7.4 through 8.6-dev.

Parameters

$argsarray

Display arguments including 'before_title', 'after_title', 'before_widget', and 'after_widget'.

$instancearray

Settings for the current RSS widget instance.

Performance profile

How much work a call to WP_Widget_RSS::widget() does, and what it touches: the algorithmic scaling, the Zend instruction count per call across PHP versions, the hooks it hands control to, and the core code that calls it. Measured from the compiled opcodes, not a stopwatch, so every number is identical on any machine running the same PHP version, and every function in core is ranked by cost.

Cost class

Heavy

Reads stored settings via get_option(), cached per request but not free on a cold cache.

Scaling

Scales with input

The body loops, so the work grows with what you pass in.

Instructions

14–212

Executed per call on PHP 8.5, depending on the branch taken. The body compiles to 235.

Plugin surface

3 hooks

Third-party callbacks on 'widget_title', 'rss_widget_feed_link', 'navigation_widgets_format' run inside this call, and their cost is not bounded by anything here.

Called by

0

Nothing in core calls this; the cost is only what you spend yourself.

What it touches

• optionoption read or writeget_option()called directly
• hookthird-party callbacksapply_filters()called directly
• cacheobject cachewp_cache_get()one call below WP_Widget_RSS::widget()
• serializeserialisationmaybe_unserialize()one call below WP_Widget_RSS::widget()

Further down the call graph this can also reach query and transient. Those are the worst case, several calls deep and usually down an error path, not what a normal call pays.

What one call costs · 230 distinct outcomes

One number would be a lie: the work depends on which branch runs. These are every distinct cost WP_Widget_RSS::widget() can have, taken from its control-flow graph on PHP 8.5.

This body has more branch combinations than are worth enumerating, so the table covers the outcomes found first rather than every one that exists.

Hooks and filters fired · 3

3 hooks fire while WP_Widget_RSS::widget() runs, in this order:

1. 1
   apply_filters( widget_title )filterline 87 (+40 into the body)

   Filters the widget title.

2. 2
   apply_filters( rss_widget_feed_link )filterline 112 (+65 into the body)

   Filters the classic RSS widget's feed icon link.

3. 3
   apply_filters( navigation_widgets_format )filterline 125 (+78 into the body)

   Filters the HTML format of widgets with navigation links.

Uses · 16

• untrailingslashit()Removes trailing forward slashes and backslashes if they exist.
• site_url()Retrieves the URL for the current site where WordPress application files (e.g. wp-blog-header.php or the wp-admin/ folder) are accessible.
• home_url()Retrieves the URL for the current site where the front end is accessible.
• fetch_feed()Builds SimplePie object based on RSS or Atom feed from URL.
• is_wp_error()Checks whether the given variable is a WordPress Error.
• esc_attr()Escaping for HTML attributes.
• get_option()Retrieves an option value based on an option name.
• __()Retrieves the translation of $text.
• apply_filters()Calls the callback functions that have been added to a filter hook.
• includes_url()Retrieves the URL to the includes directory.
• esc_url()Checks and cleans a URL.
• wp_strip_all_tags()Properly strips all HTML tags including 'script' and 'style'.

Source code

View on Trac ↗View on GitHub ↗

47	public function widget( $args, $instance ) {48		if ( isset( $instance['error'] ) && $instance['error'] ) {49			return;50		}51 52		$url = ! empty( $instance['url'] ) ? $instance['url'] : '';53		while ( ! empty( $url ) && stristr( $url, 'http' ) !== $url ) {54			$url = substr( $url, 1 );55		}56 57		if ( empty( $url ) ) {58			return;59		}60 61		// Self-URL destruction sequence.62		if ( in_array( untrailingslashit( $url ), array( site_url(), home_url() ), true ) ) {63			return;64		}65 66		$rss   = fetch_feed( $url );67		$title = $instance['title'];68		$desc  = '';69		$link  = '';70 71		if ( ! is_wp_error( $rss ) ) {72			$desc = esc_attr( strip_tags( html_entity_decode( $rss->get_description(), ENT_QUOTES, get_option( 'blog_charset' ) ) ) );73			if ( empty( $title ) ) {74				$title = strip_tags( $rss->get_title() );75			}76			$link = strip_tags( $rss->get_permalink() );77			while ( ! empty( $link ) && stristr( $link, 'http' ) !== $link ) {78				$link = substr( $link, 1 );79			}80		}81 82		if ( empty( $title ) ) {83			$title = ! empty( $desc ) ? $desc : __( 'Unknown Feed' );84		}85 86		/** This filter is documented in wp-includes/widgets/class-wp-widget-pages.php */87		$title = apply_filters( 'widget_title', $title, $instance, $this->id_base );88 89		if ( $title ) {90			$feed_url  = strip_tags( $url );91			$feed_icon = includes_url( 'images/rss.png' );92 93			$feed_link = sprintf(94				'<a class="rsswidget rss-widget-feed" href="%1$s"><img class="rss-widget-icon" style="border:0" width="14" height="14" src="%2$s" alt="%3$s"%4$s /></a> ',95				esc_url( $feed_url ),96				esc_url( $feed_icon ),97				/* translators: %s: RSS feed title. */98				esc_attr( sprintf( __( 'RSS feed: %s' ), wp_strip_all_tags( $title ) ) ),99				( wp_lazy_loading_enabled( 'img', 'rss_widget_feed_icon' ) ? ' loading="lazy"' : '' )100			);101 102			/**103			 * Filters the classic RSS widget's feed icon link.104			 *105			 * Themes can remove the icon link by using `add_filter( 'rss_widget_feed_link', '__return_empty_string' );`.106			 *107			 * @since 5.9.0108			 *109			 * @param string|false $feed_link HTML for link to RSS feed.110			 * @param array        $instance  Array of settings for the current widget.111			 */112			$feed_link = apply_filters( 'rss_widget_feed_link', $feed_link, $instance );113 114			$title = $feed_link . '<a class="rsswidget rss-widget-title" href="' . esc_url( $link ) . '">' . esc_html( $title ) . '</a>';115		}116 117		echo $args['before_widget'];118		if ( $title ) {119			echo $args['before_title'] . $title . $args['after_title'];120		}121 122		$format = current_theme_supports( 'html5', 'navigation-widgets' ) ? 'html5' : 'xhtml';123 124		/** This filter is documented in wp-includes/widgets/class-wp-nav-menu-widget.php */125		$format = apply_filters( 'navigation_widgets_format', $format );126

Changelog

Introduced in 2.8.0. Unchanged from 6.7.7 through 7.1.0.

1. 6.7.7
2. 6.8.8
3. 6.9.7
4. 7.0.4
5. 7.1.0

Signature, return type and hooks compared across 5 parsed releases.

About this page

Parsed data

Generated from the wordpress-develop 7.1.0 tag, from src/wp-includes/widgets/class-wp-widget-rss.php, and regenerated for each WordPress release so it tracks the code rather than a snapshot of it.

Corrections

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