wp_widget_rss_output( string|array|object $rss, array $args = array() )

function wp_widget_rss_output( $rss, $args = array() ) {
	if ( is_string( $rss ) ) {
		$rss = fetch_feed($rss);
	} elseif ( is_array($rss) && isset($rss['url']) ) {
		$args = $rss;
		$rss = fetch_feed($rss['url']);
	} elseif ( !is_object($rss) ) {
		return;
	}

	if ( is_wp_error($rss) ) {
		if ( is_admin() || current_user_can('manage_options') )
			echo '<p><strong>' . __( 'RSS Error:' ) . '</strong> ' . $rss->get_error_message() . '</p>';
		return;
	}

	$default_args = array( 'show_author' => 0, 'show_date' => 0, 'show_summary' => 0, 'items' => 0 );
	$args = wp_parse_args( $args, $default_args );

	$items = (int) $args['items'];
	if ( $items < 1 || 20 < $items )
		$items = 10;
	$show_summary  = (int) $args['show_summary'];
	$show_author   = (int) $args['show_author'];
	$show_date     = (int) $args['show_date'];

	if ( !$rss->get_item_quantity() ) {
		echo '<ul><li>' . __( 'An error has occurred, which probably means the feed is down. Try again later.' ) . '</li></ul>';
		$rss->__destruct();
		unset($rss);
		return;
	}

	echo '<ul>';
	foreach ( $rss->get_items( 0, $items ) as $item ) {
		$link = $item->get_link();
		while ( stristr( $link, 'http' ) != $link ) {
			$link = substr( $link, 1 );
		}
		$link = esc_url( strip_tags( $link ) );

		$title = esc_html( trim( strip_tags( $item->get_title() ) ) );
		if ( empty( $title ) ) {
			$title = __( 'Untitled' );
		}

		$desc = @html_entity_decode( $item->get_description(), ENT_QUOTES, get_option( 'blog_charset' ) );
		$desc = esc_attr( wp_trim_words( $desc, 55, ' [&hellip;]' ) );

		$summary = '';
		if ( $show_summary ) {
			$summary = $desc;

			// Change existing [...] to [&hellip;].
			if ( '[...]' == substr( $summary, -5 ) ) {
				$summary = substr( $summary, 0, -5 ) . '[&hellip;]';
			}

			$summary = '<div class="rssSummary">' . esc_html( $summary ) . '</div>';
		}

		$date = '';
		if ( $show_date ) {
			$date = $item->get_date( 'U' );

			if ( $date ) {
				$date = ' <span class="rss-date">' . date_i18n( get_option( 'date_format' ), $date ) . '</span>';
			}
		}

		$author = '';
		if ( $show_author ) {
			$author = $item->get_author();
			if ( is_object($author) ) {
				$author = $author->get_name();
				$author = ' <cite>' . esc_html( strip_tags( $author ) ) . '</cite>';
			}
		}

		if ( $link == '' ) {
			echo "<li>$title{$date}{$summary}{$author}</li>";
		} elseif ( $show_summary ) {
			echo "<li><a class='rsswidget' href='$link'>$title</a>{$date}{$summary}{$author}</li>";
		} else {
			echo "<li><a class='rsswidget' href='$link'>$title</a>{$date}{$author}</li>";
		}
	}
	echo '</ul>';
	$rss->__destruct();
	unset($rss);
}