Intercept Advanced Custom Fields (ACF) Relationship Field Searches

searchwp-customizations.php

<?php

function my_searchwp_acf_relationship_field_search( $args, $field, $post_id ) {
	if ( empty( $args['s'] ) || ! class_exists( 'SWP_Query' ) ) {
		return $args;
	}

	// Assume that the SearchWP engine to use is the defined admin search engine
	// from SearchWP's engine settings.
	$admin_engine = \SearchWP\Settings::get_admin_engine();
	$engine_name = ! empty( $admin_engine ) ? $admin_engine : 'default';

	$engine = new \SearchWP\Engine( $engine_name );
	$engine_sources = $engine->get_sources();

	if ( empty( $engine_sources ) ) {
		return array( 0 );
	}

	// Get Source post types
	$engine_sources = array_map(
		function( $source ) {
			$source_name = $source->get_name();
			$source_name_parts = explode( SEARCHWP_SEPARATOR, $source_name );
			return $source_name_parts[1] ?? false;
		},
		$engine_sources
	);

	$engine_sources = array_filter(
		$engine_sources,
		function( $source ) {
			return false !== strpos( $source, 'post' . SEARCHWP_SEPARATOR );
		},
		ARRAY_FILTER_USE_KEY
	);

	if ( empty( $engine_sources ) ) {
		return array( 0 );
	}

	$searchwp_args = array(
		'engine' => $engine_name,           // The SearchWP engine to use.
		's'      => $args['s'],             // Pass along the search query.
		'fields' => 'ids',                  // Return only post IDs.
	);

	if ( ! empty( $args['taxonomy' ] ) ) {
		$tax_arg = explode( ':', $args['taxonomy'] );

		$searchwp_args['tax_query'] = array(
			array(
				'taxonomy' => $tax_arg[0],
				'field'    => 'slug',
				'terms'    => $tax_arg[1],
			),
		);
	}

	if ( ! empty( $args['post_type'] ) ) {
		$searchwp_args['post_type'] = array_intersect( $args['post_type'], array_values( $engine_sources ) );
	}

	// Tell SearchWP to NOT log this search.
	add_filter( 'searchwp\statistics\log', '__return_false' );

	// Retrieve SearchWP results.
	$results = new SWP_Query( $searchwp_args );

	// If there are no results, we need to force ACF to reflect that.
	if ( empty( $results->posts ) ) {
		$results->posts = array( 0 );
	}

	// We're going to use SearchWP's results to handle the restrictions as outlined.
	$args['s']        = '';
	$args['order']    = '';
	$args['orderby']  = 'post__in';
	$args['post__in'] = $results->posts;

	return $args;
}

// Tell SearchWP to intercept all ACF Relationship field searches.
add_filter( 'acf/fields/relationship/query', 'my_searchwp_acf_relationship_field_search', 10, 3 );

// Tell SearchWP to intercept a single ACF Relationship field search.
// add_filter( 'acf/fields/relationship/query/name=my_acf_relationship_field_name', 'my_searchwp_acf_relationship_field_search', 10, 3 );