Call to undefined function wp_sanitize_redirect

With nginx-helper plugin installed, I get the error Call to undefined function wp_sanitize_redirect when visiting /wp-admin/ without logging in first. And the page dies without redirection. I guess this problem might appear elsewhere too.

After some digging, I discovered that wp_sanitize_redirect, along with functions such as is_user_logged_in are so called ‘pluggable’ functions. That means plugin definition takes precedence, and when no plugins defined such functions, it falls back to wordpress’ pluggable definition.

The problem with nginx-helper is that near line 340 of nginx-helper.php, you’ve overridden wp_redirect and used wp_sanitize_redirect. It gets called by wordpress to redirect the user to the login page when visiting /wp-admin/ (this could be my particular situation, I’m using a customized login page, and I’ve got other pages that will redirect if the user isn’t logged on). When this redirection happens, pluggable.php isn’t loaded yet.

To avoid this warning, may I propose the this patch to nginx-helper.php:

@@ -340,7 +340,8 @@
$status = 302;
}

– $location = wp_sanitize_redirect( $location );
+ if (function_exists(‘wp_sanitize_redirect’))
+ $location = wp_sanitize_redirect( $location );
header( ‘Location: ‘ . $location, true, $status );
}

It’s simple. It doesn’t sanitize the redirection when the function is not defined. Ideally, you could define your own copy of wp_sanitize_redirect, but I think it’ll be too much of a hassle.

I’m wondering if you could include this change in your future releases?

https://www.ads-software.com/extend/plugins/nginx-helper/