WP_REST_Users_Controller::get_items() WordPress Method

	public function get_items( $request ) {

		// Retrieve the list of registered collection query parameters.
		$registered = $this->get_collection_params();

		/*
		 * This array defines mappings between public API query parameters whose
		 * values are accepted as-passed, and their internal WP_Query parameter
		 * name equivalents (some are the same). Only values which are also
		 * present in $registered will be set.
		 */
		$parameter_mappings = array(
			'exclude'      => 'exclude',
			'include'      => 'include',
			'order'        => 'order',
			'per_page'     => 'number',
			'search'       => 'search',
			'roles'        => 'role__in',
			'capabilities' => 'capability__in',
			'slug'         => 'nicename__in',
		);

		$prepared_args = array();

		/*
		 * For each known parameter which is both registered and present in the request,
		 * set the parameter's value on the query $prepared_args.
		 */
		foreach ( $parameter_mappings as $api_param => $wp_param ) {
			if ( isset( $registered[ $api_param ], $request[ $api_param ] ) ) {
				$prepared_args[ $wp_param ] = $request[ $api_param ];
			}
		}

		if ( isset( $registered['offset'] ) && ! empty( $request['offset'] ) ) {
			$prepared_args['offset'] = $request['offset'];
		} else {
			$prepared_args['offset'] = ( $request['page'] - 1 ) * $prepared_args['number'];
		}

		if ( isset( $registered['orderby'] ) ) {
			$orderby_possibles        = array(
				'id'              => 'ID',
				'include'         => 'include',
				'name'            => 'display_name',
				'registered_date' => 'registered',
				'slug'            => 'user_nicename',
				'include_slugs'   => 'nicename__in',
				'email'           => 'user_email',
				'url'             => 'user_url',
			);
			$prepared_args['orderby'] = $orderby_possibles[ $request['orderby'] ];
		}

		if ( isset( $registered['who'] ) && ! empty( $request['who'] ) && 'authors' === $request['who'] ) {
			$prepared_args['who'] = 'authors';
		} elseif ( ! current_user_can( 'list_users' ) ) {
			$prepared_args['has_published_posts'] = get_post_types( array( 'show_in_rest' => true ), 'names' );
		}

		if ( ! empty( $request['has_published_posts'] ) ) {
			$prepared_args['has_published_posts'] = ( true === $request['has_published_posts'] )
				? get_post_types( array( 'show_in_rest' => true ), 'names' )
				: (array) $request['has_published_posts'];
		}

		if ( ! empty( $prepared_args['search'] ) ) {
			$prepared_args['search'] = '*' . $prepared_args['search'] . '*';
		}
		/**
		 * Filters WP_User_Query arguments when querying users via the REST API.
		 *
		 * @link /reference/classes/wp_user_query/
		 *
		 * @since 4.7.0
		 *
		 * @param array           $prepared_args Array of arguments for WP_User_Query.
		 * @param WP_REST_Request $request       The REST API request.
		 */
		$prepared_args = apply_filters( 'rest_user_query', $prepared_args, $request );

		$query = new WP_User_Query( $prepared_args );

		$users = array();

		foreach ( $query->results as $user ) {
			$data    = $this->prepare_item_for_response( $user, $request );
			$users[] = $this->prepare_response_for_collection( $data );
		}

		$response = rest_ensure_response( $users );

		// Store pagination values for headers then unset for count query.
		$per_page = (int) $prepared_args['number'];
		$page     = ceil( ( ( (int) $prepared_args['offset'] ) / $per_page ) + 1 );

		$prepared_args['fields'] = 'ID';

		$total_users = $query->get_total();

		if ( $total_users < 1 ) {
			// Out-of-bounds, run the query again without LIMIT for total count.
			unset( $prepared_args['number'], $prepared_args['offset'] );
			$count_query = new WP_User_Query( $prepared_args );
			$total_users = $count_query->get_total();
		}

		$response->header( 'X-WP-Total', (int) $total_users );

		$max_pages = ceil( $total_users / $per_page );

		$response->header( 'X-WP-TotalPages', (int) $max_pages );

		$base = add_query_arg( urlencode_deep( $request->get_query_params() ), rest_url( sprintf( '%s/%s', $this->namespace, $this->rest_base ) ) );
		if ( $page > 1 ) {
			$prev_page = $page - 1;

			if ( $prev_page > $max_pages ) {
				$prev_page = $max_pages;
			}

			$prev_link = add_query_arg( 'page', $prev_page, $base );
			$response->link_header( 'prev', $prev_link );
		}
		if ( $max_pages > $page ) {
			$next_page = $page + 1;
			$next_link = add_query_arg( 'page', $next_page, $base );

			$response->link_header( 'next', $next_link );
		}

		return $response;
	}