[WordPress] Removes sticky posts from WordPress default loop, sets up a custom sticky posts query. Sticky posts query can be implemented with one single template tag. Markup completely filterable. — http://glck.be/5916/

glckprss-sticky-posts.php

<?php
/**
 * Separate sticky posts from the main loop into their own query.
 *
 * Display a query of sticky posts anywhere in your templates
 * using a simple echo glckprss_sticky_posts().
 * Query template output is stored in a transient for performance win,
 * updated any time the 'sticky_posts' option get updated.
 * 
 * Require in theme’s functions.php like:
 * require get_template_directory() . '/inc/sticky-posts.php';
 *
 * @author @glueckpress
 * @author_url http://glueckpress.com
 */
if( ! class_exists( 'GlckPrss__Sticky_Posts' ) ):

	/**
	 * GlckPrss__Sticky_Posts class.
	 */
	class GlckPrss__Sticky_Posts {


		/**
		 * Removes sticky posts from main query.
		 * Updates sticky transient simultaniously with sticky_posts option.
		 *
		 * @access public
		 * @return void
		 */
		function __construct() {
			add_action( 'pre_get_posts',  array( $this, 'is_home_ignore_sticky_posts' ) );
			add_action( 'updated_option', array( $this, 'sticky_posts_query__update_transient' ), 10, 3 );
		}


		/**
		 * Remove sticky posts from main query.
		 *
		 * @access public
		 * @static
		 * @param mixed $query
		 * @return obj $query
		 */
		public static function is_home_ignore_sticky_posts( $query ) {

			if( ! is_home() )
				return $query;

			$query->set( 'ignore_sticky_posts', true );
		}


		/**
		 * The sticky posts query template.
		 *
		 * @access public
		 * @static
		 * @filtered glckprss_sticky_posts_query__post_template
		 * @return string
		 */
		public static function sticky_posts_query__query_template() {

			if( ! get_option( 'sticky_posts' ) )
				return false;

			$args = array(
				'ignore_sticky_posts' => false,
				'post__in'            => get_option( 'sticky_posts' ),
				'posts_per_page'      => -1
			);

			$sticky_posts = new WP_Query( $args );

			/*
			 * Stikcy posts loop.
			 */
			while ( $sticky_posts->have_posts() ) : $sticky_posts->the_post();

				$entry_img = has_post_thumbnail() ? wp_get_attachment_image( ( get_post_thumbnail_id() ) ) : '';

				/*
				 * To inject your own markup, use a custom function leveraging
				 * add_filter( 'glckprss_sticky_posts_query__post_template', 'foo' ).
				 */
				echo apply_filters( 'glckprss_sticky_posts_query__post_template',
					sprintf('
					<article class="sticky">
						<figure class="sticky-image"><a href="%1$s">%2$s</a></figure>
						<a href="%1$s">
							<h3 class="sticky-title">%3$s</h3>
							<div class="sticky-excerpt">
								%4$s
							</div>
						</a>
					</article>
					', get_permalink(), $entry_img, get_the_title(), get_the_excerpt() ),
				$sticky_posts, $sticky_posts, get_permalink(), $entry_img, get_the_title(), get_the_excerpt()
				);

			endwhile; // end loop

			wp_reset_query();
		}


		/**
		 * Wrap query template in a transient for better performance.
		 *
		 * @access public
		 * @static
		 * @return void
		 */
		public static function sticky_posts_query__set_transient() {

			ob_start();
			self::sticky_posts_query__query_template();

			$template = ob_get_contents();
			ob_end_clean();

			$transient = get_transient( 'glckprss_sticky_posts_query' );

			if( $transient !== $template )
				set_transient( 'glckprss_sticky_posts_query', $template ); // @todo make work for empty option sticky_posts
		}


		/**
		 * Update transient whenever option 'sticky_posts' gets updated,
		 * so we have a fresh query at all times.
		 *
		 * @access public
		 * @static
		 * @param mixed $option
		 * @param mixed $old_value
		 * @param mixed $value
		 * @return void
		 */
		public static function sticky_posts_query__update_transient( $option, $old_value, $value ) {

		 	if( 'sticky_posts' === $option ) {

			 	if( get_option( 'sticky_posts' ) )
					self::sticky_posts_query__set_transient();
				else
					delete_transient( 'glckprss_sticky_posts_query' );
			}
		}


		/**
		 * Retrieve transient, set when not present.
		 *
		 * @access public
		 * @static
		 * @return string
		 */
		public static function sticky_posts_query__get_transient() {

			$transient = get_transient( 'glckprss_sticky_posts_query' );

			if( $transient )
				return $transient;

			// Transient not set, so let’s set it now.
			self::sticky_posts_query__set_transient();

			return get_transient( 'glckprss_sticky_posts_query' );
		}
	}

	if( ! function_exists( 'glckprss_sticky_posts' ) ) :
	
		/**
		 * Template tag to retrieve sticky posts query template.
		 *
		 * @access public
		 * @param array $args (default: array())
		 * @return void
		 */
		function glckprss_sticky_posts( $args = array() ) {
	
			$default_args = array(
				'before' => '<section class="site-featured-content">',
				'after'  => '</section>'
			);
	
			$args = wp_parse_args( $args, $default_args );
	
			$sticky_posts = GlckPrss__Sticky_Posts::sticky_posts_query__get_transient();
	
			if ( ! $sticky_posts )
				return;
	
			/*
			 * Again, injecting your own markup is very easy utilizing a custom function
			 * hooking in like add_filter( 'glckprss_sticky_posts_query__post_template', 'foo' ).
			 */
			return apply_filters( 'glckprss_sticky_posts',
				$args['before'] . $sticky_posts . $args['after'],
				$args, $sticky_posts
			);
		}
	endif;
endif;

/*
 * Let there be stick.
 */
new GlckPrss__Sticky_Posts;

template-tag.php

<?php 

/* Customize wrapping element for query template */
echo glckprss_sticky_posts( 'before' => '<section class="your-class">', 'after' => '</section>' );

// Or filter from functions.php:

function your_custom_sticky_posts( $sticky_posts ) {
	
	if( ! is_home() )
		echo $sticky_posts;
}
add_filter( 'glckprss_sticky_posts', 'your_custom_sticky_posts', 10, 2 );

theme-functions.php

<?php 

/* Customize sticky posts markup. */
function your_sticky_posts_query__post_template( $template, $query, $permalink, $entry_img, $title, $excerpt ) {
	
	if( is_home() )
		return $template;
	
	printf('
		<aside class="sticky post">
			<figure class="sticky-image"><a href="%1$s">%2$s</a></figure>
			<a href="%1$s">
				<h3 class="sticky-title">%3$s</h3>
				<div class="sticky-excerpt">
					%4$s
				</div>
			</a>
		</aside>
		', get_permalink(), $entry_img, get_the_title(), get_the_excerpt() );
}
echo add_filter( 'glckprss_sticky_posts_query__post_template', 'your_sticky_posts_query__post_template', 10, 6 );