ChicagoNow Varnish configuration (development version)

wordpress.vcl

backend app1 {
    .host = "127.0.0.1";
    .port = "8000";
}   

acl purge {
	"127.0.0.1";
    "::1";
}

sub vcl_recv {
    # Filter PURGE requests
	if (req.request == "PURGE") {
		if(!client.ip ~ purge) {
			error 405 "Not allowed.";
	    }

        # Purge URLs matching a regex
		purge("req.url ~ " req.url " && req.http.host == " req.http.host);
		error 200 "Purged";
	}

    # Append X-Forwarded-For header
    if (req.http.x-forwarded-for) { 
 	    set req.http.X-Forwarded-For = req.http.X-Forwarded-For ", " client.ip; 
 	} else { 
 	    set req.http.X-Forwarded-For = client.ip; 
 	} 
	
	# Only localhost is allowed to hit PHP files directly, and they are never cached
	# This includes access to pingers   
	if (req.url ~ "^(/fabfile.py)|(/scripts/.*)|(/wp-content/.*\.php)$") {
        if(client.ip ~ purge) {
            return(pass);
        }
	
	    error 405 "Not allowed.";
	}
	
	# Pass through search requests (not worth the memory to cache them)
	if (req.url ~ "^/search/") {
	    return(pass);
	}

    # Pass through admin requests (never cache) 
    if (req.url ~ "(wp-admin|wp-comments-post|preview=true|tcc.async-upload)") {
        return(pass);
    }

    # Don't cache Wordpress core files (avoid crazy side-effects; wp-cron)
    if (req.url ~ "^/wp-.*\.php") {
        return(pass);
    }
	 
	# Strip cookies from static media
    if (req.url ~ "^/.+\.(jpeg|jpg|png|gif|ico|js|css|txt|gz|zip|lzma|bz2|tgz|tbz|swf|bmp|pdf|doc|docx|xls|xlsx|csv|avi|mov|mp3|flv|mp4)(\?.*)?$") {
       unset req.http.cookie;
    }

	# Strip cookies
	unset req.http.cookie;

    # Enable a grace period: http://www.varnish-cache.org/wiki/VCL#Grace
    set req.grace = 2m;
}
	
sub vcl_fetch {
    # Don't cache things which specifically say not to
	if (beresp.http.Cache-Control ~ "no-cache") {
	    return(pass);
	}

    # Pass through admin requests (never cache) 
    if (req.url ~ "(wp-admin|wp-comments-post|preview=true|tcc.async-upload)") {
        return(deliver);
    }

    # Don't cache Wordpress core files (avoid crazy side-effects; wp-cron)
    if (req.url ~ "^/wp-.*\.php") {
        return(pass);
    }

    # Apply caching headers -- this caching strategy from http://varnish-cache.org/wiki/VCLExampleLongerCaching
    if (beresp.cacheable) {
        # Static media
        if (req.url ~ "^/.+\.(jpeg|jpg|png|gif|ico|js|css|txt|gz|zip|lzma|bz2|tgz|tbz|swf|bmp|pdf|doc|docx|xls|xlsx|csv|avi|mov|mp3|flv|mp4)(\?.*)?$") {
            set beresp.ttl = 1w;
            set beresp.http.cache-control = "max-age = 604800, public";
        # HTML, etc.
        } else {
            set beresp.ttl = 5m;
            set beresp.http.cache-control = "max-age = 300, must-revalidate";
        }
    
        set beresp.http.cached_headers_marker = "1";
    }

    # Process Edge-side includes
    # Not currently being used on ChicagoNow
	#esi;

	# Enable a grace period: http://www.varnish-cache.org/wiki/VCL#Grace
    set req.grace = 2m;
}

sub vcl_deliver {
    # Reset Age header for reasons somewhat mysterious, see URL above re: caching strategy
    if (resp.http.cached_headers_marker) {
        unset resp.http.cached_headers_marker;
        set resp.http.age = "0";
    }

    # Add caching debugging headers
    if (obj.hits > 0) {
        set resp.http.X-Cache = "Hit";
        set resp.http.X-Cache-Hits = obj.hits;
    } else {
        set resp.http.X-Cache = "Miss";
    }
}