plugin.php

<?php

/**
 * Plugin Name: Yoast SEO for WordPress PWA
 * Description: Makes Yoast SEO settings available to WordPress PWA using the REST API.
 * Author: Pablo Postigo, Luis Herranz, Niels Garve, Tedy Warsitha, Charlie Francis
 * Version: 1.7.0
 * Plugin URI: https://github.com/wp-pwa/yoast-seo-for-wp-pwa
 */

class Yoast_To_REST_API
{
	function __construct()
	{
		add_action('rest_api_init', array($this, 'add_yoast_data'));
		add_filter('rest_prepare_latest', array($this, 'add_yoast_to_latest'), 10, 3);
	}

	function add_yoast_data()
	{
		// Custom post types (including posts and pages):
		$types = get_post_types(array('public' => true));
		foreach ($types as $key => $type) {
			register_rest_field(
				$type,
				'yoast_meta',
				array(
					'get_callback' => array($this, 'wp_api_encode_yoast'),
					'update_callback' => null,
					'schema' => null,
				)
			);
		}

		// Add custom taxonomies (including category and tag).
		$taxonomies = get_taxonomies(array('public' => true));
		foreach ($taxonomies as $key => $taxonomy) {
			if ($taxonomy === 'post_tag') $taxonomy = 'tag';
			register_rest_field(
				$taxonomy,
				'yoast_meta',
				array(
					'get_callback' => array($this, 'wp_api_encode_yoast_taxonomy'),
					'update_callback' => null,
					'schema' => null,
				)
			);
		}
	}

	function get_home_title()
	{
		$wpseo_frontend = WPSEO_Frontend_To_REST_API::get_instance();
		return $wpseo_frontend->get_title_from_options('title-home-wpseo');
	}

	function get_post_type_title($post_type)
	{
		if (intval(substr(WPSEO_VERSION, 0, 1)) < 7) {
			if ($post_type === 'page' || $post_type === 'attachment') return $post_type;
		}
		$wpseo_frontend = WPSEO_Frontend_To_REST_API::get_instance();
		$args = array('post_type' => $post_type);
		$GLOBALS['wp_query'] = new WP_Query($args);
		return $wpseo_frontend->public_get_post_type_archive_title();
	}

	function wp_api_encode_yoast($p, $field_name, $request)
	{
		$wpseo_frontend = WPSEO_Frontend_To_REST_API::get_instance();
		$args = array('p' => $p['id'], 'post_type' => 'any');
		$GLOBALS['wp_query'] = new WP_Query($args);
		return array(
			'title' => $wpseo_frontend->get_content_title(),
		);
	}

	function wp_api_encode_yoast_taxonomy($tag)
	{
		$wpseo_frontend = WPSEO_Frontend_To_REST_API::get_instance();
		$args = array('tag_id' => $tag['id']);
		$GLOBALS['wp_query'] = new WP_Query($args);
		return array(
			'title' => $wpseo_frontend->get_taxonomy_title(),
		);
	}

	function add_yoast_to_latest($response, $latest, $request)
	{
		$data = $response->data;

		if ($data['id'] === 'post') {
			$title = $this->get_home_title();
		} else {
			$id = $data['id'];
			$title = $this->get_post_type_title($id);
		}

		$data['yoast_meta'] = array(
			'title' => $title
		);

		return rest_ensure_response($data);
	}
}

function WPAPIYoast_init()
{
	if (class_exists('WPSEO_Frontend')) {
		require_once(plugin_dir_path(__FILE__) . '/classes/class-wpseo-frontend-to-rest-api.php');
		$yoast_To_REST_API = new Yoast_To_REST_API();
	} else {
		add_action('admin_notices', 'wpseo_not_loaded');
	}
}

function wpseo_not_loaded()
{
	printf(
		'<div class="error"><p>%s</p></div>',
		__('<b>Yoast SEO for WordPress PWA</b> plugin not working because <b>Yoast SEO</b> plugin is not active.')
	);
}

add_action('plugins_loaded', 'WPAPIYoast_init');