WP_REST_Posts_Controller::get_item_permissions_check PHP Method

    public function get_item_permissions_check($request)
    {
        $post = get_post((int) $request['id']);
        if ('edit' === $request['context'] && $post && !$this->check_update_permission($post)) {
            return new WP_Error('rest_forbidden_context', __('Sorry, you are not allowed to edit this post.'), array('status' => rest_authorization_required_code()));
        }
        if ($post && !empty($request['password'])) {
            // Check post password, and return error if invalid.
            if (!hash_equals($post->post_password, $request['password'])) {
                return new WP_Error('rest_post_incorrect_password', __('Incorrect post password.'), array('status' => 403));
            }
        }
        // Allow access to all password protected posts if the context is edit.
        if ('edit' === $request['context']) {
            add_filter('post_password_required', '__return_false');
        }
        if ($post) {
            return $this->check_read_permission($post);
        }
        return true;
    }

 /**
  * Check if a given request has basic access to read a snapshot.
  *
  * @param  \WP_REST_Request $request Full details about the request.
  * @return \WP_Error|boolean
  */
 public function get_item_permissions_check($request)
 {
     $error = $this->check_initial_access_permission();
     if (is_wp_error($error)) {
         return $error;
     }
     return parent::get_item_permissions_check($request);
 }