HTTP cacheing: do not store the date header with the resource

... to avoid re-writing the resource to disk when retrieving the
resource from cache. We are currently using the "Expires", "max-age"
and "s-maxage" headers to determine when a cached resource will expire.

Autotests still pass and the demo browser reports the same amount of
pages loaded from the cache.

Reviewed-by: Markus Goetz

1 files changed, 5 insertions, 8 deletions

diff --git a/src/network/access/qnetworkaccesshttpbackend.cpp b/src/network/access/qnetworkaccesshttpbackend.cpp
index 108ac68..7c90f68 100644
--- a/src/network/access/qnetworkaccesshttpbackend.cpp
+++ b/src/network/access/qnetworkaccesshttpbackend.cpp
@@ -1001,14 +1001,11 @@ QNetworkCacheMetaData QNetworkAccessHttpBackend::fetchCacheMetaData(const QNetwo
         if (hop_by_hop)
             continue;
 
-        // for 4.6.0, we were planning to not store the date header in the
-        // cached resource; through that we planned to reduce the number
-        // of writes to disk when using a QNetworkDiskCache (i.e. don't
-        // write to disk when only the date changes).
-        // However, without the date we cannot calculate the age of the page
-        // anymore.
-        //if (header == "date")
-            //continue;
+        // we are currently not using the date header to determine the expiration time of a page,
+        // but only the "Expires", "max-age" and "s-maxage" headers, see
+        // QNetworkAccessHttpBackend::validateCache() and below ("metaData.setExpirationDate()").
+        if (header == "date")
+            continue;
 
         // Don't store Warning 1xx headers
         if (header == "warning") {