render_block_core_rss( array $attributes ): string

Compatibility

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

Parameters

$attributesarray

The block attributes.

Return value

string

Returns the block content with received rss items.

Performance profile

How much work a call to render_block_core_rss() 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

21–98

Executed per call on PHP 8.5, depending on the branch taken. The body compiles to 283.

Plugin surface

None

Nothing here hands control to plugin code.

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()one call below render_block_core_rss()
• cacheobject cachewp_cache_get()one call below render_block_core_rss()
• serializeserialisationmaybe_unserialize()one call below render_block_core_rss()

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 · 5 distinct outcomes

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

Uses · 14

• 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.
• __()Retrieves the translation of $text.
• 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_html()Escaping for HTML blocks.
• esc_attr()Escaping for HTML attributes.
• esc_url()Checks and cleans a URL.
• get_option()Retrieves an option value based on an option name.
• date_i18n()Retrieves the date in localized format, based on a sum of Unix timestamp and timezone offset in seconds.
• wp_trim_words()Trims text to a certain number of words.

Source code

View on Trac ↗View on GitHub ↗

17function render_block_core_rss( $attributes ) {18	if ( in_array( untrailingslashit( $attributes['feedURL'] ), array( site_url(), home_url() ), true ) ) {19		return '<div class="components-placeholder"><div class="notice notice-error">' . __( 'Adding an RSS feed to this site’s homepage is not supported, as it could lead to a loop that slows down your site. Try using another block, like the <strong>Latest Posts</strong> block, to list posts from the site.' ) . '</div></div>';20	}21 22	$rss = fetch_feed( $attributes['feedURL'] );23 24	if ( is_wp_error( $rss ) ) {25		return '<div class="components-placeholder"><div class="notice notice-error"><strong>' . __( 'RSS Error:' ) . '</strong> ' . esc_html( $rss->get_error_message() ) . '</div></div>';26	}27 28	if ( ! $rss->get_item_quantity() ) {29		return '<div class="components-placeholder"><div class="notice notice-error">' . __( 'An error has occurred, which probably means the feed is down. Try again later.' ) . '</div></div>';30	}31 32	$rss_items  = $rss->get_items( 0, $attributes['itemsToShow'] );33	$list_items = '';34 35	$open_in_new_tab = ! empty( $attributes['openInNewTab'] );36	$rel             = ! empty( $attributes['rel'] ) ? trim( $attributes['rel'] ) : '';37 38	$link_attributes = '';39 40	if ( $open_in_new_tab ) {41		$link_attributes .= ' target="_blank"';42	}43 44	if ( '' !== $rel ) {45		$link_attributes .= ' rel="' . esc_attr( $rel ) . '"';46	}47 48	foreach ( $rss_items as $item ) {49		$title = esc_html( trim( strip_tags( html_entity_decode( $item->get_title() ) ) ) );50 51		if ( empty( $title ) ) {52			$title = __( '(no title)' );53		}54		$link = $item->get_link();55		$link = esc_url( $link );56 57		if ( $link ) {58			$title = "<a href='{$link}'{$link_attributes}>{$title}</a>";59		}60		$title = "<div class='wp-block-rss__item-title'>{$title}</div>";61 62		$date_markup = '';63		if ( ! empty( $attributes['displayDate'] ) ) {64			$timestamp = $item->get_date( 'U' );65 66			if ( $timestamp ) {67				$gmt_offset = get_option( 'gmt_offset' );68				$timestamp += (int) ( (float) $gmt_offset * HOUR_IN_SECONDS );69 70				$date_markup = sprintf(71					'<time datetime="%1$s" class="wp-block-rss__item-publish-date">%2$s</time> ',72					esc_attr( date_i18n( 'c', $timestamp ) ),73					esc_html( date_i18n( get_option( 'date_format' ), $timestamp ) )74				);75			}76		}77 78		$author = '';79		if ( $attributes['displayAuthor'] ) {80			$author = $item->get_author();81			if ( is_object( $author ) ) {82				$author = $author->get_name();83				if ( ! empty( $author ) ) {84					$author = '<span class="wp-block-rss__item-author">' . sprintf(85						/* translators: byline. %s: author. */86						__( 'by %s' ),87						esc_html( strip_tags( $author ) )88					) . '</span>';89				}90			}91		}92 93		$excerpt     = '';94		$description = $item->get_description();95		if ( $attributes['displayExcerpt'] && ! empty( $description ) ) {96			$excerpt = html_entity_decode( $description, ENT_QUOTES, get_option( 'blog_charset' ) );

Changelog

Introduced in 5.2.0. 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/blocks/rss.php, and regenerated for each WordPress release so it tracks the code rather than a snapshot of it.

Corrections

Something wrong on this page? Report it and it gets fixed in the next regeneration.