Varnish VCL for Magento

backend apache {
  .host = "127.0.0.1";
  .port = "81";
  .max_connections = 256;
  .connect_timeout = 30s;
  .first_byte_timeout = 30s;
  .between_bytes_timeout = 30s;

# need to create ping.html in public_html directory with just a line like "PONG!"
  .probe = {
    .url = "/ping.html";
    .timeout = 10s;
    .window = 8;
    .threshold = 3;
  }
}

acl purge {
  "localhost";
}

sub vcl_recv {
set req.http.host = "example.net";
  #purge all
  if (req.request == "PURGE") {
    if (!client.ip ~ purge) {
      error 405 "Not allowed.";
    }
    if (req.url ~ "varnish/index/purgeall/key/#Fj1nzljh") {
     purge( ".*" );
    }
  }

  #described below need to create random "DynamicPage" value; this functionallity we use
  #to create several caches for 1 dynamic page.
  #for example, "int i = rand() % 2 + 1;" means that we have 2 different copies of one dynamic page
#  C{
#   char buffer [33];
#   int i = rand() % 10 + 1;
#   sprintf(buffer, "%d", i);
#   VRT_SetHdr(sp, HDR_REQ, "\014DynamicPage:", buffer, vrt_magic_string_end);
#  }C

  if (req.request != "GET" &&
  req.request != "HEAD" &&
  req.request != "PUT" &&
  req.request != "POST" &&
  req.request != "TRACE" &&
  req.request != "OPTIONS" &&
  req.request != "DELETE") {
    return (pipe);
  }

  # do not cache POST requests
  if (req.request == "POST") {
    return (pipe);
  }

  #we should not cache any page for Magento backend
  if (req.request == "GET" && (req.url ~ "^/admin") || req.url ~ "^/index.php/admin") {
    return (pass);
  }

  #we should not cache any page for checkout and customer modules
  if (req.request == "GET" && (req.url ~ "^/checkout" || req.url ~ "^/customer")) {
    return (pass);
  }

  #do not cache till session end
  if (req.http.cookie ~ "nocache_stable") {
    return (pass);
  }

  #unique identifier witch tell Varnish use cache or not
  if (req.http.cookie ~ "nocache") {
    return (pass);
  }

  if (req.request == "GET" && (req.url ~ "\.(png|jpg|jpeg|gif)$" || req.url ~ "print.css")) {
    return (lookup);
  }

  #Even though there are few possible values for Accept-Encoding, Varnish treats
  #them literally rather than semantically, so even a small difference which makes
  #no difference to the backend can reduce cache efficiency by making Varnish cache
  #too many different versions of an object.
  #http://varnish.projects.linpro.no/wiki/FAQ/Compression
  if (req.http.Accept-Encoding) {
    if (req.url ~ "\.(jpg|png|gif|gz|tgz|bz2|tbz|mp3|ogg)$") {
      # No point in compressing these
      remove 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 {
      # unkown algorithm
      remove req.http.Accept-Encoding;
    }
  }

  return (lookup);
}

sub vcl_pipe {
  # Note that only the first request to the backend will have
  # X-Forwarded-For set.  If you use X-Forwarded-For and want to
  # have it set for all requests, make sure to have:
  # set req.http.connection = "close";
  # here.  It is not set by default as it might break some broken web
  # applications, like IIS with NTLM authentication.
  return (pipe);
}

sub vcl_pass {
  return (pass);
}

sub vcl_hit {
  if (!obj.cacheable) {
    return (pass);
  }
  return (deliver);
}

sub vcl_miss {
  return (fetch);
}

sub vcl_fetch {
  return (deliver);
}

sub vcl_deliver {

  if (obj.hits > 0) {
    set resp.http.X-Cache = "HIT";
  } else {
    set resp.http.X-Cache = "MISS";
  }
}

sub vcl_error {
 set obj.http.Content-Type = "text/html; charset=utf-8";
 synthetic {"
 <?xml version="1.0" encoding="utf-8"?>
 <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN"
 "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
 <html>
 <head>
 <title>"} obj.status " " obj.response {"</title>
 </head>
 <body>
 <h1>Error "} obj.status " " obj.response {"</h1>
 <p>"} obj.response {"</p>
 <h3> :</h3>
 <p>URL: "} obj.http.bhash {"</p>
 <p>XID: "} req.xid {"</p>
 <hr>
 <address>
 <a href="http://www.varnish-cache.org/">Nexcess cache server</a>
 </address>
 </body>
 </html>
 "};
 return (deliver);
}