No-cache HTTP response headers added to appropriate web-client servlets.

git-svn-id: https://svn.alfresco.com/repos/alfresco-enterprise/alfresco/HEAD/root@5827 c4b6b30b-aa2e-2d43-bbcb-ca4b014f7261

source/java/org/alfresco/web/app/servlet/BaseServlet.java

@@ -188,6 +188,15 @@ public abstract class BaseServlet extends HttpServlet
       }
    }
    
+   /**
+    * Apply the headers required to disallow caching of the response in the browser
+    */
+   public static void setNoCacheHeaders(HttpServletResponse res)
+   {
+      res.setHeader("Cache-Control", "no-cache");
+      res.setHeader("Pragma", "no-cache");
+   }
+   
    /**
     * Returns true if the specified JSP file is valid for a redirect after login.
     * Only a specific sub-set of the available JSPs are valid to jump directly too after a

source/java/org/alfresco/web/app/servlet/CommandServlet.java

@@ -96,6 +96,8 @@ public class CommandServlet extends BaseServlet
          return;
       }
       
+      setNoCacheHeaders(res);
+      
       uri = uri.substring(req.getContextPath().length());
       StringTokenizer t = new StringTokenizer(uri, "/");
       int tokenCount = t.countTokens();

source/java/org/alfresco/web/app/servlet/ExternalAccessServlet.java

@@ -100,6 +100,8 @@ public class ExternalAccessServlet extends BaseServlet
          return;
       }
       
+      setNoCacheHeaders(res);
+      
       uri = uri.substring(req.getContextPath().length());
       StringTokenizer t = new StringTokenizer(uri, "/");
       int tokenCount = t.countTokens();

source/java/org/alfresco/web/app/servlet/TemplateContentServlet.java

@@ -114,6 +114,8 @@ public class TemplateContentServlet extends BaseTemplateContentServlet
          return;
       }
       
+      setNoCacheHeaders(res);
+      
       processTemplateRequest(req, res, true);
    }