From 76c056c7a17c343b40e1663cd90d4aa0accb3f6e Mon Sep 17 00:00:00 2001
From: Sandro Santilli <strk@keybit.net>
Date: Mon, 15 Jul 2013 13:14:06 +0200
Subject: [PATCH] Revert "Use a constant Last-Modified time with
 cache_policy=persist"

This reverts commit 4b5899ff1aec8c6682585bd2789179da3eed40d2.

The reason is that setting Last-Modified to a remote date in the past
triggers early expiration of cache (as max-age will be reached sooner)
---
 lib/cartodb/server_options.js | 16 +++++++---------
 1 file changed, 7 insertions(+), 9 deletions(-)

diff --git a/lib/cartodb/server_options.js b/lib/cartodb/server_options.js
index 33fe8e87..86c607f3 100644
--- a/lib/cartodb/server_options.js
+++ b/lib/cartodb/server_options.js
@@ -213,20 +213,18 @@ module.exports = function(){
         if ( req.params.token ) cache_policy = 'persist';
         if ( cache_policy == 'persist' ) {
           res.header('Cache-Control', 'public,max-age=31536000'); // 1 year
-          // Set Last-Modified header to a constant time in the past
-          res.header('Last-Modified', new Date(0).toUTCString());
         } else {
           var ttl = global.environment.varnish.ttl || 86400;
           res.header('Cache-Control', 'no-cache,max-age='+ttl+',must-revalidate, public');
-          // Set Last-Modified header
-          //
-          // Currently sets it to NOW
-          //
-          // TODO: find out a real value, querying for most recent change in
-          //       any of the source tables
-          res.header('Last-Modified', new Date().toUTCString());
         }
 
+        // Set Last-Modified header
+        //
+        // Currently sets it to NOW
+        //
+        // TODO: find out a real value, querying for most recent change in
+        //       any of the source tables
+        res.header('Last-Modified', new Date().toUTCString());
 
         me.generateCacheChannel(req, function(err, channel){
             if ( ! err ) {