[WP MU] Shortcode for custom loops between different blogs - For WordPress Multisite MU

mu_loop.php

<?php

// This is a work in progress, but it works fine
// Requires custom functions & libraries not present in the script (eg. Swiper)
// Adapted from my Visual Composer custom module (same purpose) https://gist.github.com/Jany-M/7a94e2edc04969dcded247ff99a15088
// Doesn't play well with WPML, for now

function shambix_shortcode_mu_posts($atts, $content = null ) {
 
	// Let's compare parameters with defaults
	$atts = shortcode_atts( array(
		'blog_id' => '1',
		'title'   => '',
		'post_type'   => 'post',
		'number'   => '',
		'number'   => '',
		'post_order' => 'date',
		//'show_date' => false,
		//'show_featured' => true,
		//'featured_size' => 'thumbnail',
		//'featured_size_custom' => '',
		'class' => '',
		//'row_width' => true,
		'tax' => '',
		'tax_terms' => ''
	), $atts );

	// posts per page
	if($atts['number']) {
		$posts_per_page = $atts['number'];
	} else {
		$posts_per_page = get_option('posts_per_page');
	}

	// Blog IDs
	if( $atts['blog_id'] ) {
		$sites = explode(',',$atts['blog_id']);
	}

	// apply post types
	if( $atts['post_type'] ) {
		$post_types = explode(',',$atts['post_type']);
	}

	if( $atts['tax'] ) {
		$tax = $atts['tax'];
	}
	if( $atts['tax_terms'] ) {
		$terms = explode(',',$atts['tax_terms']);
	}

	// Current Blog ID is important
	global $current_blog_id;
	$current_blog_id = get_current_blog_id();

	/*if(defined('ICL_LANGUAGE_CODE')) {
		$lang = ICL_LANGUAGE_CODE;
   } else {
		$lang = 'it';
   }*/

	// Cat
	/*if($cat != '') {
		$tax_args['tax_query'][] = array(
			'taxonomy' => 'category',
			'field' => 'slug',
			'terms' => $cat,
		);
		$args = array_merge( $args, $tax_args );
	}*/

	// ARGS
	//$max = 12;
	
    $latest_news_args = array(
		//'posts_per_page' => $max,
		//'post_type' => array('post'),
		'posts_per_page' => $posts_per_page,
		'post_type' => $post_types,
		'post_status' => 'publish',
		'orderby' =>  $atts['post_order'],
		'order' => 'DESC',
	);
		
	// START
	$html = '<div class="vc_multisite_posts ' . $atts['class'] . '">';

	$html .= '<!-- Blog -->
	<div class="blog">
		<div class="triangolo_giallo left"></div>
		<div class="container-fluid">';

		if( $atts['title'] ) {
			$html .= '<h3 class="h2_title">' . $atts['title'] . '</h3>';
		}
		
	$html .= '<div class="swiper-container">
		<div class="swiper-wrapper">';
	
	
	// Looping all the sites and adding posts
	foreach( $sites as $site ) {

		switch_to_blog( $site );

		// RESETS
		$i = $skipped = '0';
		$target = '';

		// Adjust depending on Blog ID
		if(get_current_blog_id() != $current_blog_id) {

			// Links target
			$target = 'target="_blank"';

			// WPML only show posts in same lang - DOESNT WORK
			/*if(defined('ICL_LANGUAGE_CODE')) {
				$latest_news_args['suppress_filters'] = false;
				//$latest_news_args['suppress_filters'] = 'FALSE',
				
				//global $sitepress;
				//$sitepress->switch_lang($lang);
				do_action( 'wpml_switch_language', $lang);

				// Because WPML doesnt work
				$latest_news_args['posts_per_page'] = -1;

			}*/

		}

		// If tax + term
		// https://wordpress.stackexchange.com/questions/189035/get-all-terms-inside-a-specific-taxonomy-in-a-multisite

		if($tax != '' && $terms != '') {
			$check_later = array();
			global $wp_taxonomies;
			$loop_tax = explode(',',$atts['tax']);
			foreach($loop_tax as $taxonomy){
				if (isset($wp_taxonomies[$taxonomy])){
					$check_later[$taxonomy] = false;
				} else {
					$wp_taxonomies[$taxonomy] = true;
					$check_later[$taxonomy] = true;
				}
			}
			$tax_args = array(
				'tax_query' => array(
					'operator' => 'AND',
					array(
						'taxonomy' => $tax,
						'field'    => 'slug',
						'terms'    => $terms,
					),
				)
			);
			$latest_news_args = array_merge( $latest_news_args, $tax_args );

		}

		// QUERY THE POSTS

		// Check if values are cached, if not cache them
		$theme_slug = str_replace(' ', '_', THEME_SLUG);
    	$latest_news_transient = $theme_slug.'_latest_news_blogID_'.$current_blog_id.'_transient_24h';
    	//delete_transient($latest_news_transient);
    	if(get_transient($latest_news_transient) === false) {

			$latest_news_transient_loop = new WP_Query($latest_news_args);
		
			//Cache Results
			set_transient($latest_news_transient, $latest_news_transient_loop, 24 * HOUR_IN_SECONDS );
		}
		$latest_news_transient_loop = get_transient($latest_news_transient);
		$count = $latest_news_transient_loop->post_count;

		// TODO: If more than one blog, need to merge all sites' posts into one big post result and limit with posts_per_page
			
		if( $latest_news_transient_loop->have_posts() ) : while( $latest_news_transient_loop->have_posts() ) : $latest_news_transient_loop->the_post();

			global $post;
			$post_id = $post->ID;
			$i++;

			if(has_post_thumbnail($post_id)) {
				$img_id = get_post_thumbnail_id($post_id);
				$full_img_url = get_the_post_thumbnail_url($post_id,'full'); 
				$full_img_src = wp_imager(400, 600, 1, null, false, $full_img_url, true);
			}

			// Cats
			$post_categories = wp_get_post_categories($post_id);
			$cats = array();
			foreach($post_categories as $c){
				$cat = get_category( $c );
				$cats[] = '<li>'.$cat->name.'</li>';
			}
			$cats = implode(' ', $cats);
						
			// WPML
			/*if(defined('ICL_LANGUAGE_CODE')) {
					
				//$translated_slug = apply_filters( 'wpml_get_translated_slug', 'product', 'product', $lang); // apply_filters doesnt work on MU

				// Awful workaround because it wont query the correct lang -_-
				$post_lang = apply_filters( 'wpml_post_language_details', NULL, get_the_ID());
				if($post_lang["language_code"] != $lang) {
					$skipped++;
					continue;
				}
			}*/

			$html .= '<div class="swiper-slide">';

			$html .= '<div id="slide-'.$i.'" class="blog_item">
				<div class="inner">
					<div class="post-feature-overlay">
						<div class="post-feature" data-responsive-background-image>
							<img src="'.$full_img_src.'; ?>" srcset="'.wp_get_attachment_image_srcset( $img_id, 'medium' ).'" sizes="'.wp_get_attachment_image_sizes( $img_id, 'medium' ).'" />
						</div>
						<div class="post-overlay"></div>
					</div>
					<div class="post-info">
						<ul class="post-categories">'.$cats.'</ul>
						<h3><a href="'.get_the_permalink().'" alt="'.get_the_title().'">'.get_the_title().'</a></h3>
						<hr />
						<!-- <div class="post-date"><p> //the_time("j F Y")</p></div> -->
						<div class="post-excerpt">
							'.custom_excerpt(24).'
						</div>
						<div class="post-read-more">
							<a class="btn btn-giallo" href="'.get_the_permalink().'">Leggi</a>
						</div>
					</div>
				</div>
			</div>';

			$html .= '</div>';

		endwhile; endif; wp_reset_query(); wp_reset_postdata();
	
	
		// Debug
		/*if(get_current_blog_id() != $current_blog_id) {
			if(current_user_can('administrator')) {
				echo '<pre>';
				var_dump($skipped);
				echo '</pre>';
			}
		}*/

		/* Skipped diff langs posts - Integrate with new query then */
		/*if($skipped > 0) {

			$latest_news_args['posts_per_page'] = $skipped;
			$latest_news_transient_loop = new WP_Query($latest_news_args);

			if( $latest_news_transient_loop->have_posts() ) :

		}*/

		// RESET
		// If tax + term
		if($tax != '' && $terms != '') {
			if (isset($check_later))
				foreach($check_later as $taxonomy => $unset)
					if ($unset == true)
						unset($wp_taxonomies[$taxonomy]);
		}

		//restore_current_blog();

	} // end foreach site
	
	$html .= '</div>
		<div class="swiper-pagination"></div>
		<div class="swiper-button-prev"></div>
		<div class="swiper-button-next"></div>
	</div>';

	$html .= "<script type='text/javascript'>
		// Swiper News
		var mySwiper_News = new Swiper ('.blog .swiper-container', {
			normalizeSlideIndex: true,
			slidesPerView: 4,
			slidesPerGroup: 4,
			loopedSlides: 4,
			spaceBetween: 30,
			direction: 'horizontal',
			loop: true,
			grabCursor: true,

			pagination: {
				el: '.swiper-pagination',
			},
			navigation: {
				nextEl: '.swiper-button-next',
				prevEl: '.swiper-button-prev',
			}
		});
	</script>";

	$html .= '</div>
		<div class="triangolo_giallo right"></div>
	</div>';

	return $html;

	restore_current_blog();

}
add_shortcode('mu_posts', 'shambix_shortcode_mu_posts');

?>