某个位置的自定义快速 cgi 缓存持续时间

Question

我有这个配置

location ~* \.php$ {
        try_files $uri /index.php =404;
        fastcgi_pass phpstream;
        fastcgi_index index.php;
        fastcgi_cache GCache;
        fastcgi_cache_valid 200 120m;
        fastcgi_cache_min_uses 1;
}

我想让持续时间对某些位置而不是120m所有位置都动态，所以我尝试了

location ~* \.php$ {
        try_files $uri /index.php =404;
        fastcgi_pass phpstream;
        fastcgi_index index.php;

        set $duration = 120m;
        if ($request_uri ~ ^/([0-9]+)/$) { 
            set $duration 30s;
        }

        fastcgi_cache GCache;
        fastcgi_cache_valid 200 $duration;
        fastcgi_cache_min_uses 1;
}

但我得到了错误

2022/08/21 22:11:12 [emerg] 1#1: invalid time value "$duration" in /etc/nginx/conf.d/data.conf
nginx: [emerg] invalid time value "$duration" in /etc/nginx/conf.d/data.conf

我想让动态内容每 30 秒更新一次，这样如果动态内容更新，它就会每 30 秒更新一次，但其余部分则不同