nginx caching per user agent

Question

I'm currently using nginx as reverse proxy with caching enabled.

However, the main site has two different layouts, depending on the user-agent (mobile or not).

I've tried something similar to this:

    # mobile users
    if ($http_user_agent ~* '(iPhone|iPod|mobile|Android|2.0\ MMP|240x320|AvantGo|BlackBerry|Blazer|Cellphone|Danger|DoCoMo|Elaine/3.0|EudoraWeb|hiptop|IEMobile)') {
            set $iphone_request '1';
    }
    if ($iphone_request = '1') {
            proxy_cache        mobile;
    }
    if ($iphone_request = '') {
            proxy_cache        site;
    }
    proxy_cache_key    "$scheme://$host$request_uri";
    proxy_pass         http://real-site.tld;

However, nginx gives an error, stating proxy_cache can't be used in an if-structure.

Any other way to serve from a different cache depending on the browser?

Thanks, Tuinslak

Answer 1

Why using different cache? Probably it would be sufficient to define your cache key based on $iphone_request variable?

proxy_cache_key "$iphone_request$uri";

Answer 2

Redirect to subdomain for mobile devices (with different caching policy)?