Get cf7 form list

class-cf7-list.php

<?php
/**
 * List all CF7 forms
 *
 * @package   CF7_List
 * @author    Maksym Denysenko
 * @link      https://github.com/mdenisenko/
 * @copyright Copyright © 2019
 * @license   GPL-2.0+
 * @wordpress-theme
 */

/**
 * Class CF7_List
 */
class CF7_List {

	/**
	 * CF7_List constructor.
	 */
	public function __construct() {
		add_action( 'save_post', [ $this, 'clear_cache' ], 10 );
	}

	/**
	 * Get CF7 form list
	 *
	 * @return array
	 */
	public function get_cf7_forms(): array {
		global $wpdb;
		$forms = wp_cache_get( 'cf7-forms' );
		if ( empty( $forms ) ) {
			// phpcs:disable WordPress.DB.DirectDatabaseQuery.DirectQuery
			$forms = $wpdb->get_results(
				$wpdb->prepare(
					'SELECT ID, post_title FROM ' . $wpdb->posts . ' WHERE post_type = %s', "wpcf7_contact_form"
				)
			);
			// phpcs:enable WordPress.DB.DirectDatabaseQuery.DirectQuery
			$forms = wp_list_pluck( $forms, 'post_title', 'ID' );
			wp_cache_add( 'cf7-forms', $forms );
		}

		return $forms;
	}

	/**
	 * Delete CF7 forms cache
	 *
	 * @param int     $post_id Post id.
	 * @param WP_Post $post    Post.
	 */
	public function clear_cache( int $post_id, WP_Post $post ) {
		if ( 'wpcf7_contact_form' === $post->post_type ) {
			wp_cache_delete( 'cf7-forms' );
		}
	}

}