Custom parameters for Algolia search in WordPress

algolia-2.php

<?php

add_filter( 'algolia_terms_index_settings', '__return_empty_array' );
add_filter( 'algolia_users_index_settings', '__return_empty_array' );

add_filter( 'algolia_posts_listing_index_settings', 'mytheme_algolia_listing_settings' );

function mytheme_algolia_listing_settings( $settings ){
	$numeric_fields = array_keys( mytheme_algolia_faceted_fields( array( 'int', 'float' ) ) );
	$string_fields = array_keys( mytheme_algolia_faceted_fields( 'string' ) );

	$settings = array(
	    'attributesToIndex' => array(
	        'unordered(post_title)',
	        'unordered(content)'
	    ),
	    'customRanking' => array(
	        'desc(post_date)',
	        'desc(price)',
	        'desc(city)',
	    ),
	    'attributeForDistinct'  => 'post_id',
	    'distinct'              => true,
	    'numericAttributesForFiltering' => $numeric_fields,
	    'attributesForFaceting' => $string_fields,
	    'attributesToSnippet' => array(
	        'post_title:30',
	        'content:30',
	    ),
	    'snippetEllipsisText' => '…',
	);

	return $settings;
}

add_filter( 'algolia_post_listing_shared_attributes', 'mytheme_algolia_listing_custom_meta', 10, 2 );

function mytheme_algolia_listing_custom_meta( array $shared_attributes, WP_Post $post ) {

	$remove_fields = array(
		'comment_count',
		'menu_order',
		'post_author',
		'post_type_label',
		'images',
		'post_mime_type',
		'taxonomies',
		'taxonomies_hierarchical',
		'is_sticky',
		'alt',
		'metadata'
	);

	foreach( $remove_fields as $field ){
		if( isset( $shared_attributes[ $field ] ) )
			unset( $shared_attributes[ $field ] );
	}

	$listing = new MY_Listing( $post->ID );

	if( ! $listing )
		return $shared_attributes;

	$searchable_fields = mytheme_algolia_faceted_fields();

	foreach( $searchable_fields as $field => $type ){
		$method = 'get_' . $field;
		$meta_key = '_listing_' . $field;


		if( $value = $listing->_get_field( $field ) ){ // this doesn't work  :(
			settype( $value, $type );
			$shared_attributes[ $field ] = $value;
		} elseif( $value = $listing->$method() ) { // this doesn't work  :(
			settype( $value, $type );
			$shared_attributes[ $field ] = $value;
		} elseif( $value = get_post_meta( $post->ID, $meta_key, true ) ) {
			settype( $value, $type );
			$shared_attributes[ $field ] = $value;
		}
	}

    return $shared_attributes;
}

function mytheme_algolia_faceted_fields( $types = array() ){
	if( $types && ! is_array( $types ) )
		$types = array( $types );

	$fields = array(
		'mls' => 'string',
		'price' => 'float',
		'status' => 'string',
		'listing_class' => 'string',
		'acres' => 'float',
		'number_bedrooms' => 'int',
		'number_total_bathrooms' => 'float',
		'address_street' => 'string',
		'city' => 'string',
		'zip' => 'string',
		'county' => 'string',
		'subdivision' => 'string',
		'elementary_school' => 'string',
		'intermediate_school' => 'string',
		'middle_school' => 'string',
		'high_school' => 'string',
		'year_built' => 'int',
		'latitude' => 'float',
		'longitude' => 'float',
	);

	if( ! $types )
		return $fields;

	$return = array();
	foreach( $fields as $field => $type ){
		if( in_array( $type, $types ) ){
			$return[ $field ] = $type;
		}
	}

	return $return;
}

function mytheme_algolia_get_posts( $search ){

	/*
	  'hits' => array [results]
	  'nbHits' => int 36947
	  'page' => int 0
	  'nbPages' => int 19
	  'hitsPerPage' => int 54
	 */

	$post_ids = wp_list_pluck( $search['hits'], 'post_id' );

	$args = array(
		'post_type' => 'listing',
		'post_status' => 'publish',
		'posts_per_page' => $search['hitsPerPage'],
		'post__in' => $post_ids
	);

	$query = new WP_Query( $args );
	$query->found_posts = $search['nbHits'];
	$query->max_num_pages = $search['nbPages'];
	$query->paged = $search['page'];

	return $query;
}

algolia.php

<?php

add_filter( 'algolia_post_listing_shared_attributes', 'mytheme_algolia_listing_custom_meta', 10, 2 );

function mytheme_algolia_listing_custom_meta( array $shared_attributes, WP_Post $post ) {

	$remove_fields = array(
		'comment_count',
		'menu_order',
		'post_author',
		'post_type_label',
		'images',
		'post_mime_type',
		'taxonomies',
		'taxonomies_hierarchical',
		'is_sticky',
		'alt',
		'metadata'
	);

	foreach( $remove_fields as $field ){
		if( isset( $shared_attributes[ $field ] ) )
			unset( $shared_attributes[ $field ] );
	}

	$listing = new MY_Listing( $post->ID );

	if( ! $listing )
		return $shared_attributes;

	$searchable_fields = array(
		'mls',
		'price',
		'status',
		'listing_class',
		'acres',
		'number_bedrooms',
		'number_total_bathrooms',
		'address_street',
		'city',
		'zip',
		'county',
		'subdivision',
		'elementary_school',
		'intermediate_school',
		'middle_school',
		'high_school',
		'year_built',
		'latitude',
		'longitude',
	);

	foreach( $searchable_fields as $field ){
		$method = 'get_' . $field;
		$meta_key = '_listing_' . $field;

		if( $value = $listing->_get_field( $field ) ){ // this doesn't work  :(
			$shared_attributes[ $field ] = $value;
		} elseif( $value = $listing->$method() ) { // this doesn't work  :(
			$shared_attributes[ $field ] = $value;
		} elseif( $value = get_post_meta( $post->ID, $meta_key, true ) ) {
			$shared_attributes[ $field ] = $value;
		}
	}

    return $shared_attributes;
}

In addition to my incoming support answer, here is how you could cast your attributes to integers:

if ( is_numeric( $value ) ) {
    $value = (float) $value;
}