set $nocache 0; # internal variable for bypassing the cache, nginx expects 0/1 for boolean
proxy_cache skynet; # cache name
proxy_cache_key $skylink_v1$path$arg_format$arg_attachment$arg_start$arg_end$http_range; # unique cache key
proxy_cache_valid 200 206 24h; # cache 200 and 206 responses for 24 hours
proxy_cache_bypass $nocache $cookie_nocache $arg_nocache; # add cache bypass option
add_header X-Proxy-Cache $upstream_cache_status; # add response header to indicate cache hits and misses