default.vcl

# Marker to tell the VCL compiler that this VCL has been written with the
# 4.0 or 4.1 syntax.
vcl 4.1;

import std;

# Default backend definition. Set this to point to your content server.
backend default {
    .host = "127.0.0.1";
    .port = "8080";
}

sub vcl_recv {
    # Happens before we check if we have this in cache already.
    #
    # Typically you clean up the request here, removing cookies you don't need,
    # rewriting the request, etc.

    # If HTTPS, the backend needs to know
    if (std.port(server.ip) == 443) {
        set req.http.X-Forwarded-Proto = "https";
    }
    # If not HTTPS, redirect to HTTPS
    if (req.http.X-Forwarded-Proto !~ "https") {
        return (synth(850, "Moved Permanently"));
    }
    
    # set to Gzip, deflate or remove entirely
    if (req.http.Accept-Encoding) {
        if (req.url ~ "\.(jpg|jpeg|png|gif|gz|tgz|bz2|tbz|mp3|mp4|ogg)$") {
          unset req.http.Accept-Encoding;
        } elsif (req.http.Accept-Encoding ~ "gzip") {
          set req.http.Accept-Encoding = "gzip";
        } elsif (req.http.Accept-Encoding ~ "deflate") {
          set req.http.Accept-Encoding = "deflate";
        } else {
          unset req.http.Accept-Encoding;
        }
    }

    return(hash);
}

sub vcl_backend_response {
    # Happens after we have read the response headers from the backend.
    #
    # Here you clean the response headers, removing silly Set-Cookie headers
    # and other mistakes your backend does.

    set beresp.grace = 2m;
    set beresp.keep = 8m;

    # We clear the Varnish cache when needed, so keep here for longer
    set beresp.ttl = 1d;
    
    # Do not Gzip image files in Varnish
    if (beresp.http.url ~ "\.(jpg|jpeg|png|gif|gz|tgz|bz2|tbz|mp3|mp4|ogg|swf)$") {
     set beresp.do_gzip = false;
    }
    else {
     set beresp.do_gzip = true;
     set beresp.http.X-Cache = "ZIP";
    }

    # GZip the cached content if possible
    if (beresp.http.content-type ~ "text") {
     set beresp.do_gzip = true;
    }
}

sub vcl_deliver {
    # Happens when we have all the pieces we need, and are about to send the
    # response to the client.
    #
    # You can do accounting or modifying the final object here.
}

sub vcl_synth {
    if (resp.status == 301 || resp.status == 302) {
        set resp.http.location = resp.reason;
        set resp.reason = "Moved";
        return (deliver);
    }

    # Synthetic response for redirecting to HTTPS
    if(resp.status == 850) {
        set resp.http.Location = "https://" + req.http.host + req.url;
        set resp.status = 301;
        return(deliver);
    }
}

sub vcl_hash {
    # We want to cache http and https separately, so we can cache the redirects
    hash_data(req.http.X-Forwarded-Proto);
    hash_data(req.http.X-IsLoggedIn);
}