Varnish WordPress config

default.vcl

vcl 4.0;
import directors;
import std;

backend default {
	.host = "nginx";
	.port = "80";
}

acl purge {
	"localhost";
	"127.0.0.1";
	"php";
}

sub vcl_recv {
	# Only a single backend
	set req.backend_hint = default;

	# Setting http headers for backend
	set req.http.X-Forwarded-For = client.ip;
	set req.http.X-Forwarded-Proto = "https";

	# Unset headers that might cause us to cache duplicate infos
	unset req.http.Accept-Language;
	unset req.http.User-Agent;

	# The purge...no idea if this works
	if (req.method == "PURGE") {
		if (!client.ip ~ purge) {
			return(synth(405, "Not allowed."));
		}
		return(purge);
	}

	# drop cookies and params from static assets
	if (req.url ~ "\.(gif|jpg|jpeg|swf|ttf|css|js|flv|mp3|mp4|pdf|ico|png)(\?.*|)$") {
		unset req.http.cookie;
		set req.url = regsub(req.url, "\?.*$", "");
	}

	# drop tracking params
	if (req.url ~ "\?(utm_(campaign|medium|source|term)|adParams|client|cx|eid|fbid|feed|ref(id|src)?|v(er|iew))=") {
		set req.url = regsub(req.url, "\?.*$", "");
	}

	# pass wp-admin urls
	if (req.url ~ "(wp-login|wp-admin)" || req.url ~ "preview=true" || req.url ~ "xmlrpc.php") {
		return(pass);
	}

	# pass wp-admin cookies
	if (req.http.cookie) {
		if (req.http.cookie ~ "(wordpress_|wp-settings-)") {
			return(pass);
		} else {
			unset req.http.cookie;
		}
	}
}

sub vcl_backend_response {
	# retry a few times if backend is down
	if (beresp.status == 503 && bereq.retries < 3) {
		return(retry);
	}

	if (bereq.http.Cookie ~ "(UserID|_session)") {
		# if we get a session cookie...caching is a no-go
		set beresp.http.X-Cacheable = "NO:Got Session";
		set beresp.uncacheable = true;

		return(deliver);
	} elsif (beresp.ttl <= 0s) {
		# Varnish determined the object was not cacheable
		set beresp.http.X-Cacheable = "NO:Not Cacheable";
	} elsif (beresp.http.set-cookie) {
		# You don't wish to cache content for logged in users
		set beresp.http.X-Cacheable = "NO:Set-Cookie";
		set beresp.uncacheable = true;

		return(deliver);
	} elsif (beresp.http.Cache-Control ~ "private") {
		# You are respecting the Cache-Control=private header from the backend
		set beresp.http.X-Cacheable = "NO:Cache-Control=private";
		set beresp.uncacheable = true;

		return(deliver);
	} else {
		# Varnish determined the object was cacheable
		set beresp.http.X-Cacheable = "YES";

		# Remove Expires from backend, it's not long enough
		unset beresp.http.expires;

		# Set the clients TTL on this object
		set beresp.http.cache-control = "max-age=900";

		# Set how long Varnish will keep it
		set beresp.ttl = 1w;

		# marker for vcl_deliver to reset Age:
		set beresp.http.magicmarker = "1";
	}

	# unset cookies from backendresponse
	if (!(bereq.url ~ "(wp-login|wp-admin)"))  {
		set beresp.http.X-UnsetCookies = "TRUE";
		unset beresp.http.set-cookie;
		set beresp.ttl = 1h;
	}

	# long ttl for assets
	if (bereq.url ~ "\.(gif|jpg|jpeg|swf|ttf|css|js|flv|mp3|mp4|pdf|ico|png)(\?.*|)$") {
		set beresp.ttl = 1d;
	}

	set beresp.grace = 1w;
}

sub vcl_hash {
	if (req.http.X-Forwarded-Proto) {
		hash_data(req.http.X-Forwarded-Proto);
	}
}

sub vcl_backend_error {
	# display custom error page if backend down
	if (beresp.status == 503 && bereq.retries == 3) {
		synthetic(std.fileread("/etc/varnish/error503.html"));
		return(deliver);
	}
}

sub vcl_synth {
	# redirect for http
	if (resp.status == 750) {
		set resp.status = 301;
		set resp.http.Location = req.http.x-redir;
		return(deliver);
	}
	# display custom error page if backend down
	if (resp.status == 503) {
		synthetic(std.fileread("/etc/varnish/error503.html"));
		return(deliver);
	}
}

sub vcl_deliver {
	# oh noes backend is down
	if (resp.status == 503) {
		return(restart);
	}
	if (resp.http.magicmarker) {
		# Remove the magic marker
		unset resp.http.magicmarker;

		# By definition we have a fresh object
		set resp.http.age = "0";
	}
	if (obj.hits > 0) {
		set resp.http.X-Cache = "HIT";
	} else {
		set resp.http.X-Cache = "MISS";
	}
	set resp.http.Access-Control-Allow-Origin = "*";
}

sub vcl_hit {
	if (req.method == "PURGE") {
		return(synth(200, "OK"));
	}
}

sub vcl_miss {
	if (req.method == "PURGE") {
		return(synth(404, "Not cached"));
	}
}