Set Expires Header only if upstream has not already set an Expires

[Thomas Glanzmann]

Hello francis,

> > Howto set expires only if upstream does not have set an expires?

> * Francis Daly <francis at daoine.org> [2017-11-23 00:26]:

> You can set a value based on $upstream_http_expires --

> { default off; "" 7d; }

> in the appropriate "map" should set your Expires time to 7 days from
> now if there is not an Expires: header from the upstream.

thanks a lot. That solved my problem. I used the same:

map $upstream_http_expires $expires {
	default off;
	"" 7d;
}

server {
...
	expires $expires;
}

Works like a charm. Thank you again for solving my problem. I thought about
using a map but missed the 'off' possibility and its behaviour.

Cheers,
        Thomas