Flush cache when php user is different to nginx user

I am also searching for a cache purging solution.
This plugin does unlink( $cache ); but this is not advised:
https://trac.nginx.org/nginx/ticket/767

I am still looking for an nginx-way solution.

Do you know https://github.com/FRiCKLE/ngx_cache_purge ?
It is packaged in DotDeb.

If I understand correctly
https://nginx.org/en/docs/http/ngx_http_fastcgi_module.html#fastcgi_cache_purge
“is available as part of our commercial subscription.”

I haven’t tested it yet but a proxy_cache per fastcgi_pass instance may solve my per user permissions problem but I also realized that it’s really the nginx process owner that is doing the deleting so it’s up to me to arrange for the nginx PID to have access to each separate vhost/vuser cache store. If that makes sense.

For my situation I am thinking I’d be better off using a plugin to create static files and store them on tmpfs because clearing the right cached files on demand, although possible, also seems too unreliable.