Jetpack Infinite Scroll: Posts ordered by meta value

infinite-scroll-orderby-meta.php

<?php
// Inspired by Isotrope code: https://gist.github.com/isotrope/1930f90518bdbfa074c3 and MCSF https://gist.github.com/mcsf/6c5cda9ee61acc8849c6

// Creates a query var called "tri"
function query_vars_tri( $vars ){
	$vars[] = "tri";
	return $vars;
}
add_filter( 'query_vars', 'query_vars_tri' );

// Posts ordered by queryvar "tri"
function posts_orderby_tri($query) {

	if(!is_admin()){
		if($query->is_main_query() ){
			if(in_array($query->query_vars['tri'],array('general', 'pertinence', 'bienetre', 'protection', 'vieprivee', 'innovation', 'prixplus', 'prixmoins'))){

				$order = 'DESC';
				if($query->query_vars['tri']=='prixplus' || $query->query_vars['tri']=='prixmoins')
					$meta_key = '_infos_prix';
				else
					$meta_key = '_rating_'.$query->query_vars['tri'];

				if($query->query_vars['tri']=='prixmoins')
					$order = 'ASC';

				$orderby = 'meta_value_num';
				$query->set('orderby', $orderby);
				$query->set('meta_key', $meta_key);
				$query->set('order',$order);
			}
		}
	}
}
add_action('pre_get_posts','posts_orderby_tri');

// Whitelists the `extra` variable that holds the predicates, so that IS doesn't ignore it when reconstructing the original query using the query args from the IS AJAX request                                                                            * request.
function infinite_scroll_allowed_vars_extra( $allowed_vars ) {
	$allowed_vars[] = 'extra';

	return $allowed_vars;
}
add_filter( 'infinite_scroll_allowed_vars', 'infinite_scroll_allowed_vars_extra' );

// Includes a few useful predicates in the bootstrapped `infiniteScroll` JS object that is served along with the rest of the document upon initial page request.
function infinite_scroll_js_settings_extra( $js_settings ) {

	$js_settings['text'] = __( "Plus de contenus", "pla" );

	$js_settings['query_args']['extra'] = array(
		'tri'       => get_query_var( 'tri' ) ,
	);

	return $js_settings;
}
add_filter( 'infinite_scroll_js_settings', 'infinite_scroll_js_settings_extra' );


// Apply sorting methods to jetpacks queries using the "tri" query var
function infinite_scroll_query_args_tri( $query_args ) {

	if(in_array($query_args['extra']['tri'],array('general', 'pertinence', 'bienetre', 'protection', 'vieprivee', 'innovation', 'prixplus', 'prixmoins'))){
		$order = 'DESC';
		if($query_args['extra']['tri']=='prixplus' || $query_args['extra']['tri']=='prixmoins')
			$meta_key = '_infos_prix';
		else
			$meta_key = '_rating_'.$query_args['extra']['tri'];

		if($query_args['extra']['tri']=='prixmoins')
			$order = 'ASC';

		$orderby = 'meta_value_num';

		$query_args['orderby'] = $orderby;
		$query_args['meta_key'] = $meta_key;
		$query_args['order'] = $order;
		$query_args['offset'] = $query_args['posts_per_page'] * $query_args['paged'];
	}


	return $query_args;
}
add_filter( 'infinite_scroll_query_args', 'infinite_scroll_query_args_tri',11 );