microcache.inc

# Setup var defaults
set $no_cache "";

# If non GET/HEAD, don't cache & mark user as uncacheable for 1 second via cookie
if ($request_method !~ ^(GET|HEAD)$) {
    set $no_cache "1";
}

# Drop no cache cookie if need be
# (for some reason, add_header fails if included in prior if-block)
if ($no_cache = "1") {
    add_header Set-Cookie "_mcnc=1; Max-Age=2; Path=/";
    add_header X-Microcachable "0";
}

# Bypass cache if no-cache cookie is set
if ($http_cookie ~* "_mcnc") {
    set $no_cache "1";
}

# Bypass cache if flag is set
proxy_no_cache $no_cache;
proxy_cache_bypass $no_cache;

# Set cache zone
proxy_cache microcache;

# Set cache key to include identifying components
proxy_cache_key $scheme$host$request_method$request_uri;

# Cache 404 responses fro 30 minutes
proxy_cache_valid 404 30m;

# Only cache valid HTTP 200 responses for 5 seconds
proxy_cache_valid 200 30s;

# Serve from cache if currently refreshing
proxy_cache_use_stale updating;

# Set files larger than 1M to stream rather than cache
proxy_max_temp_file_size 1M;

# Custom logging
access_log /var/log/nginx/microcache.log custom_microcache;