From a6449221db29f20511edac00a3640bd7cbffc02d Mon Sep 17 00:00:00 2001
From: Kevin Roast <kevin.roast@alfresco.com>
Date: Fri, 11 Aug 2006 14:16:52 +0000
Subject: [PATCH] . Added support for 'Last-Modified' response header value and
 'If-Modified-Since' request header value in the DownloadContentServlet.   -
 browsers can now correctly cache Alfresco content based on last-modified date
 of the node.

git-svn-id: https://svn.alfresco.com/repos/alfresco-enterprise/alfresco/HEAD/root@3485 c4b6b30b-aa2e-2d43-bbcb-ca4b014f7261
---
 .../app/servlet/DownloadContentServlet.java    | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)

diff --git a/source/java/org/alfresco/web/app/servlet/DownloadContentServlet.java b/source/java/org/alfresco/web/app/servlet/DownloadContentServlet.java
index ea9835c25b..951f1c2b3f 100644
--- a/source/java/org/alfresco/web/app/servlet/DownloadContentServlet.java
+++ b/source/java/org/alfresco/web/app/servlet/DownloadContentServlet.java
@@ -21,6 +21,7 @@ import java.io.UnsupportedEncodingException;
 import java.net.SocketException;
 import java.net.URLEncoder;
 import java.text.MessageFormat;
+import java.util.Date;
 import java.util.StringTokenizer;
 
 import javax.servlet.ServletException;
@@ -35,6 +36,7 @@ import org.alfresco.service.cmr.repository.ContentReader;
 import org.alfresco.service.cmr.repository.ContentService;
 import org.alfresco.service.cmr.repository.MimetypeService;
 import org.alfresco.service.cmr.repository.NodeRef;
+import org.alfresco.service.cmr.repository.NodeService;
 import org.alfresco.service.cmr.repository.StoreRef;
 import org.alfresco.service.cmr.security.AccessStatus;
 import org.alfresco.service.cmr.security.PermissionService;
@@ -170,6 +172,7 @@ public class DownloadContentServlet extends BaseServlet
       
       // get the services we need to retrieve the content
       ServiceRegistry serviceRegistry = getServiceRegistry(getServletContext());
+      NodeService nodeService = serviceRegistry.getNodeService();
       ContentService contentService = serviceRegistry.getContentService();
       PermissionService permissionService = serviceRegistry.getPermissionService();
       
@@ -184,6 +187,21 @@ public class DownloadContentServlet extends BaseServlet
             return;
          }
          
+         // check If-Modified-Since header and set Last-Modified header as appropriate
+         Date modified = (Date)nodeService.getProperty(nodeRef, ContentModel.PROP_MODIFIED);
+         long modifiedSince = req.getDateHeader("If-Modified-Since");
+         if (modifiedSince > 0L)
+         {
+             // round the date to the ignore millisecond value which is not supplied by header
+             long modDate = (modified.getTime() / 1000L) * 1000L;
+             if (modDate <= modifiedSince)
+             {
+                 res.setStatus(304);
+                 return;
+             }
+         }
+         res.setDateHeader("Last-Modified", modified.getTime());
+         
          if (attachment == true)
          {
             // set header based on filename - will force a Save As from the browse if it doesn't recognise it