Posts tagged in multiple sites

tag-multisite.php

/**
 * Alter the tags inline query so that it returns date in addition to ID
 * 
 * @global hyperdb $wpdb
 * @param string $fields
 * @return string
 */
function _filter_fields_id_date() {
	global $wpdb;
	return "{$wpdb->posts}.ID, {$wpdb->posts}.post_date";
}

/**
 * Alter the tags inline, remove the fields param
 * 
 * @param WP_Query $query
 */
function _remove_fields_from_query( &$query ) {
	$query->set( 'fields', '' );
}

/**
 * Query and cache id, date, blog_id for posts in eMusic and 17 Dots sites
 * tagged with the current tag
 * 
 * @param boolean $all
 * @return array
 */
function get_topic_post_IDs( $all = false ) {
	$key = 'topic-posts-' . get_query_var( 'tag' );
	$group = 'topics';
	$posts = wp_cache_get( $key, $group );

	if ( empty( $posts ) ) {
		add_filter( 'posts_fields', '_filter_fields_id_date', 1000 );
		add_action( 'parse_query', '_remove_fields_from_query', 1000 );
		
		$emusic_data = _type_taxonomy_region_ids( '', get_query_var( 'tag' ) );

		if ( empty( $emusic_data ) ) {
			$emusic_data = array();
		} else {
			foreach ( $emusic_data as &$emusic_post ) {
				$p = (array) $emusic_post;
				$emusic_post = $p;
				$emusic_post['blog_id'] = 1;  
			} 
		}

		switch_to_blog( 3 );
		$dots_data = _type_taxonomy_region_ids( 'post', get_query_var( 'tag' ) );
		if ( empty( $dots_data ) ) {
			$dots_data = array();
		} else {
			foreach ( $dots_data as &$dots_post ) {
				$p = (array) $dots_post;
				$dots_post = $p;
				$dots_post['blog_id'] = 3;  
			} 
		}
		
		remove_filter( 'posts_fields', '_filter_fields_id_date', 1000 );
		remove_action( 'parse_query', '_remove_fields_from_query', 1000 );

		restore_current_blog(); 

		$times = array();
		$posts = array();
		foreach ( array_merge( $emusic_data, $dots_data ) as $i => $post ) {
			$incr = $i;
			$time = strtotime( $post['post_date'] );
			if ( in_array( $time + $incr, $times ) )
				$incr = $i + 5; 

			$posts[$time + $incr] = $post;
			$times[] = $time + $incr;
		}

		krsort( $posts );

		wp_cache_set( $key, $posts, $group, 120 );
	}

	if ( ! $all ) {
		$start = (int) get_query_var( 'paged' ) ? ( get_query_var( 'paged' ) - 1 ) * get_query_var( 'posts_per_page' ) : 0;
		$posts = array_slice( $posts, $start, get_query_var( 'posts_per_page' ) );
	}

	return $posts;
}

/**
 * Returns IDs for posts queried by post_type, term, and taxonomy
 * 
 * @access private
 * @param mixed $post_type
 * @param string $term
 * @param string $taxonomy
 * @return array
 */
function _type_taxonomy_region_ids( $post_type = 'post', $term = '', $taxonomy = 'post_tag' ) {
	$the_term = get_term_by( 'slug', $term, $taxonomy );
	
	if ( ! empty( $the_term ) ) {
		if ( empty( $post_type ) && 1 === get_current_blog_id() )
			$post_type = get_emusic_post_types();
		
		$results = new WP_Query( array( 
			'fields'	=> 'ids',
			'post_type' => $post_type,
			'tax_query' => array(
				get_region_tax_query(),
				array(
					'operator' => 'IN',
					'taxonomy' => $taxonomy, 
					'field'	=> 'term_taxonomy_id',
					'terms'	=> array( $the_term->term_taxonomy_id ),
					'include_children' => false
				),
				'relation' => 'AND'
			)
		) );
		
		return $results->posts;
	}
}