varnish config

backend default {
    .host = "127.0.0.1";
    .port = "8080";
}
# Block 2: Define a key based on the User-Agent which can be used for hashing.
# Also set the PS-CapabilityList header for PageSpeed server to respect.
sub generate_user_agent_based_key {
    # Define placeholder PS-CapabilityList header values for large and small
    # screens with no UA dependent optimizations. Note that these placeholder
    # values should not contain any of ll, ii, dj, jw or ws, since these
    # codes will end up representing optimizations to be supported for the
    # request.
    set req.http.default_ps_capability_list_for_large_screens = "LargeScreen.SkipUADependentOptimizations:";
    set req.http.default_ps_capability_list_for_small_screens = "TinyScreen.SkipUADependentOptimizations:";

    # As a fallback, the PS-CapabilityList header that is sent to the upstream
    # PageSpeed server should be for a large screen device with no browser
    # specific optimizations.
    set req.http.PS-CapabilityList = req.http.default_ps_capability_list_for_large_screens;

    # Cache-fragment 1: Desktop User-Agents that support lazyload_images (ll),
    # inline_images (ii) and defer_javascript (dj).
    # Note: Wget is added for testing purposes only.
    if (req.http.User-Agent ~ "(?i)Chrome/|Firefox/|MSIE |Safari|Wget") {
      set req.http.PS-CapabilityList = "ll,ii,dj:";
    }
    # Cache-fragment 2: Desktop User-Agents that support lazyload_images (ll),
    # inline_images (ii), defer_javascript (dj), webp (jw) and lossless_webp
    # (ws).
    if (req.http.User-Agent ~
        "(?i)Chrome/[2][3-9]+\.|Chrome/[[3-9][0-9]+\.|Chrome/[0-9]{3,}\.") {
      set req.http.PS-CapabilityList = "ll,ii,dj,jw,ws:";
    }
    # Cache-fragment 3: This fragment contains (a) Desktop User-Agents that
    # match fragments 1 or 2 but should not because they represent older
    # versions of certain browsers or bots and (b) Tablet User-Agents that
    # on all browsers and use image compression qualities applicable to large
    # screens. Note that even Tablets that are capable of supporting inline or
    # webp images, e.g. Android 4.1.2, will not get these advanced
    # optimizations.
    if (req.http.User-Agent ~ "(?i)Firefox/[1-2]\.|MSIE [5-8]\.|bot|Yahoo!|Ruby|RPT-HTTPClient|(Google \(\+https\:\/\/developers\.google\.com\/\+\/web\/snippet\/\))|Android|iPad|TouchPad|Silk-Accelerated|Kindle Fire") {
      set req.http.PS-CapabilityList = req.http.default_ps_capability_list_for_large_screens;
    }
    # Cache-fragment 4: Mobiles and small screen Tablets will use image compression
    # qualities applicable to small screens, but all other optimizations will be
    # those that work on all browsers.
    if (req.http.User-Agent ~ "(?i)Mozilla.*Android.*Mobile*|iPhone|BlackBerry|Opera Mobi|Opera Mini|SymbianOS|UP.Browser|J-PHONE|Profile/MIDP|portalmmm|DoCoMo|Obigo|Galaxy Nexus|GT-I9300|GT-N7100|HTC One|Nexus [4|7|S]|Xoom|XT907") {
      set req.http.PS-CapabilityList = req.http.default_ps_capability_list_for_small_screens;
    }
    # Remove placeholder header values.
    remove req.http.default_ps_capability_list_for_large_screens;
    remove req.http.default_ps_capability_list_for_large_screens;
}


# Drop any cookies sent to Wordpress.
# except when previewing
sub vcl_recv {
    if ( !(req.url ~ "(wp-login|wp-admin|preview=true)") ) {
        unset req.http.cookie;
    }
}

sub vcl_hash {
  # Block 3: Use the PS-CapabilityList value for computing the hash.
  hash_data(req.http.PS-CapabilityList);
}

# Block 3a: Define ACL for purge requests
acl purge {
  # Purge requests are only allowed from localhost.
  "localhost";
  "127.0.0.1";
}
# Block 3b: Issue purge when there is a cache hit for the purge request.
sub vcl_hit {
  if (req.request == "PURGE") {
    purge;
    error 200 "Purged.";
  }
}

# Block 3c: Issue a no-op purge when there is a cache miss for the purge
# request.
sub vcl_miss {
  if (req.request == "PURGE") {
     purge;
     error 200 "Purged.";
  }
}

# Block 4: In vcl_recv, on receiving a request, call the method responsible for
# generating the User-Agent based key for hashing into the cache.

sub vcl_recv {
  call generate_user_agent_based_key;
  # Block 3d: Verify the ACL for an incoming purge request and handle it.
  if (req.request == "PURGE") {
    if (!client.ip ~ purge) {
      error 405 "Not allowed.";
    }
    return (lookup);
  }
  # Blocks which decide whether cache should be bypassed or not go here.

  # Block 5a: Bypass the cache for .pagespeed. resource. PageSpeed has its own
  # cache for these, and these could bloat up the caching layer.
  if (req.url ~ "\.pagespeed\.([a-z]\.)?[a-z]{2}\.[^.]{10}\.[^.]+") {
    # Skip the cache for .pagespeed. resource.  PageSpeed has its own
    # cache for these, and these could bloat up the caching layer.
    return (pass);
  }
 # Block 5b: Only cache responses to clients that support gzip.  Most clients
  # do, and the cache holds much more if it stores gzipped responses.
  if (req.http.Accept-Encoding !~ "gzip") {
    return (pass);
  }
}
# Block 6: Mark HTML uncacheable by caches beyond our control.
sub vcl_fetch {
   if (beresp.http.Content-Type ~ "text/html") {
     # Hide the upstream cache control header.
     remove beresp.http.Cache-Control;
     # Add no-cache Cache-Control header for html.
     set beresp.http.Cache-Control = "no-cache, max-age=0";
   }
   return (deliver);
}

# Block 7: Add a header for identifying cache hits/misses.
sub vcl_deliver {
  if (obj.hits > 0) {
    set resp.http.X-Cache = "HIT";
  } else {
    set resp.http.X-Cache = "MISS";
  }
}


# Drop any cookies Wordpress tries to send back to the client.
# except when previewing
sub vcl_fetch {
    if ( !(req.url ~ "(wp-login|wp-admin|preview=true)") ) {
        unset beresp.http.set-cookie;
    }
}