Integrate with WPGraphQL to check if the current user has access to certain post types.

my-pmpro-wpgraphql-private-posts.php

<?php
/**
 * Integrate with WPGraphQL to check if the current user has access to certain post types.
 *
 * You can add this recipe to your site by creating a custom plugin
 * or using the Code Snippets plugin available for free in the WordPress repository.
 * Read this companion article for step-by-step directions on either method.
 * https://www.paidmembershipspro.com/create-a-plugin-for-pmpro-customizations/
 */

function my_pmpro_wpgraphql_data_is_private( $is_private, $model_name, $data ) {
	// Bypass if the object is already private.
	if ( ! $is_private ) {
		return $is_private;
	}
	
	// Confirm PMPro is available.
	if ( ! function_exists( 'pmpro_has_membership_access' ) ) {
		return $is_private;
	}

	// Check which models we want to support.
	if ( $model_name !== 'PostObject' ) {
		return $is_private;
	}

	// Default supported post types.
	$supported_post_types = [
		'post' => true,
		'page' => true,
	];

	// Check for custom post type support.
	if ( function_exists( 'pmprocpt_getCPTs' ) ) {
		$pmpro_cpts = pmprocpt_getCPTs();

		foreach ( $pmpro_cpts as $cpt ) {
			$supported_post_types[ $cpt ] = true;
		}
	}

	// Only run access checks for supported post types.
	if ( ! isset( $supported_post_types[ $data->post_type ] ) ) {
		return $is_private;
	}

	return pmpro_has_membership_access( $data->ID );
}

add_filter( 'graphql_data_is_private', 'my_pmpro_wpgraphql_data_is_private', 10, 3 );