skynet-webportal/docker/nginx/conf.d/include/proxy-cache-downloads

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_min_uses 3; # cache after 3 uses
proxy_cache_valid 200 206 307 308 48h; # keep 200, 206, 307 and 308 responses valid for up to 2 days
add_header X-Proxy-Cache $upstream_cache_status; # add response header to indicate cache hits and misses

# map skyd env variable value to "1" for true and "0" for false (expected by proxy_no_cache)
set_by_lua_block $skyd_disk_cache_enabled {
    return os.getenv("SKYD_DISK_CACHE_ENABLED") == "true" and "1" or "0"
}

# bypass - this will bypass cache hit on request (status BYPASS)
# but still stores file in cache if cache conditions are met
proxy_cache_bypass $cookie_nocache $arg_nocache $skyd_disk_cache_enabled;

# no cache - this will ignore cache on request (status MISS)
# and does not store file in cache under no condition
set_if_empty $nocache "0";

# disable cache when nocache is set or skyd cache is enabled
proxy_no_cache $nocache $skyd_disk_cache_enabled;