allow static public files to be cached on drupal sites

cache public static files from drupal

templates/presets/drupal.vcl.tmpl

@@ -11,9 +11,10 @@ sub vcl_recv {
     }
 
     # Remove all cookies that Drupal doesn't need to know about. We explicitly
-    # list the ones that Drupal does need, the SESS and NO_CACHE. If, after
-    # running this code we find that either of these two cookies remains, we
-    # will pass as the page cannot be cached.
+    # list the ones that Drupal does need, the SESS and NO_CACHE. If no cookies
+    # remain then the page can be cached.
+    # If some cookies do remain, the response still might be cached by static.vcl
+    # if the request is for a public static file.
     if (req.http.Cookie) {
         {{ $preserved_cookies := (getenv "VARNISH_DRUPAL_PRESERVED_COOKIES" "SESS[a-z0-9]+|SSESS[a-z0-9]+|NO_CACHE") }}
 
@@ -37,10 +38,11 @@ sub vcl_recv {
             # the page.
             unset req.http.Cookie;
         }
-        else {
-            # If there is any cookies left (a session or NO_CACHE cookie), do not
-            # cache the page. Pass it on to Apache directly.
-            return (pass);
-        }
     }
 }
+
+
+sub vcl_backend_response {
+    # Set the default TTL
+    set beresp.ttl = {{ getenv "VARNISH_DEFAULT_TTL" "120s" }};
+}