Sending and receiving heartbeat requests (#9265)

4 files changed, 71 insertions, 4 deletions

diff --git a/server/src/com/vaadin/terminal/gwt/server/AbstractApplicationPortlet.java b/server/src/com/vaadin/terminal/gwt/server/AbstractApplicationPortlet.java
index bd39504237..dea42b6b69 100644
--- a/server/src/com/vaadin/terminal/gwt/server/AbstractApplicationPortlet.java
+++ b/server/src/com/vaadin/terminal/gwt/server/AbstractApplicationPortlet.java
@@ -340,7 +340,7 @@ public abstract class AbstractApplicationPortlet extends GenericPortlet
     }
 
     protected enum RequestType {
-        FILE_UPLOAD, UIDL, RENDER, STATIC_FILE, APPLICATION_RESOURCE, DUMMY, EVENT, ACTION, UNKNOWN, BROWSER_DETAILS, CONNECTOR_RESOURCE;
+        FILE_UPLOAD, UIDL, RENDER, STATIC_FILE, APPLICATION_RESOURCE, DUMMY, EVENT, ACTION, UNKNOWN, BROWSER_DETAILS, CONNECTOR_RESOURCE, HEARTBEAT;
     }
 
     protected RequestType getRequestType(WrappedPortletRequest wrappedRequest) {
@@ -361,6 +361,8 @@ public abstract class AbstractApplicationPortlet extends GenericPortlet
             } else if (ServletPortletHelper
                     .isApplicationResourceRequest(wrappedRequest)) {
                 return RequestType.APPLICATION_RESOURCE;
+            } else if (ServletPortletHelper.isHeartbeatRequest(wrappedRequest)) {
+                return RequestType.HEARTBEAT;
             } else if (isDummyRequest(resourceRequest)) {
                 return RequestType.DUMMY;
             } else {
@@ -431,6 +433,7 @@ public abstract class AbstractApplicationPortlet extends GenericPortlet
             Application application = null;
             boolean transactionStarted = false;
             boolean requestStarted = false;
+            boolean applicationRunning = false;
 
             try {
                 // TODO What about PARAM_UNLOADBURST & redirectToApplication??
@@ -459,6 +462,10 @@ public abstract class AbstractApplicationPortlet extends GenericPortlet
                     applicationManager.serveConnectorResource(wrappedRequest,
                             wrappedResponse);
                     return;
+                } else if (requestType == RequestType.HEARTBEAT) {
+                    applicationManager.handleHeartbeatRequest(wrappedRequest,
+                            wrappedResponse, application);
+                    return;
                 }
 
                 /* Update browser information from request */
@@ -477,6 +484,7 @@ public abstract class AbstractApplicationPortlet extends GenericPortlet
 
                 /* Start the newly created application */
                 startApplication(request, application, applicationContext);
+                applicationRunning = true;
 
                 /*
                  * Transaction starts. Call transaction listeners. Transaction
@@ -585,6 +593,11 @@ public abstract class AbstractApplicationPortlet extends GenericPortlet
                 handleServiceException(wrappedRequest, wrappedResponse,
                         application, e);
             } finally {
+
+                if (applicationRunning) {
+                    application.closeInactiveRoots();
+                }
+
                 // Notifies transaction end
                 try {
                     if (transactionStarted) {
diff --git a/server/src/com/vaadin/terminal/gwt/server/AbstractApplicationServlet.java b/server/src/com/vaadin/terminal/gwt/server/AbstractApplicationServlet.java
index 062ba6cdf7..0fc8bc09a0 100644
--- a/server/src/com/vaadin/terminal/gwt/server/AbstractApplicationServlet.java
+++ b/server/src/com/vaadin/terminal/gwt/server/AbstractApplicationServlet.java
@@ -248,6 +248,7 @@ public abstract class AbstractApplicationServlet extends HttpServlet implements
         Application application = null;
         boolean transactionStarted = false;
         boolean requestStarted = false;
+        boolean applicationRunning = false;
 
         try {
             // If a duplicate "close application" URL is received for an
@@ -287,6 +288,10 @@ public abstract class AbstractApplicationServlet extends HttpServlet implements
             if (requestType == RequestType.CONNECTOR_RESOURCE) {
                 applicationManager.serveConnectorResource(request, response);
                 return;
+            } else if (requestType == RequestType.HEARTBEAT) {
+                applicationManager.handleHeartbeatRequest(request, response,
+                        application);
+                return;
             }
 
             /* Update browser information from the request */
@@ -304,6 +309,7 @@ public abstract class AbstractApplicationServlet extends HttpServlet implements
 
             // Start the application if it's newly created
             startApplication(request, application, webApplicationContext);
+            applicationRunning = true;
 
             /*
              * Transaction starts. Call transaction listeners. Transaction end
@@ -354,6 +360,11 @@ public abstract class AbstractApplicationServlet extends HttpServlet implements
         } catch (final Throwable e) {
             handleServiceException(request, response, application, e);
         } finally {
+
+            if (applicationRunning) {
+                application.closeInactiveRoots();
+            }
+
             // Notifies transaction end
             try {
                 if (transactionStarted) {
@@ -1121,7 +1132,7 @@ public abstract class AbstractApplicationServlet extends HttpServlet implements
     }
 
     protected enum RequestType {
-        FILE_UPLOAD, BROWSER_DETAILS, UIDL, OTHER, STATIC_FILE, APPLICATION_RESOURCE, CONNECTOR_RESOURCE;
+        FILE_UPLOAD, BROWSER_DETAILS, UIDL, OTHER, STATIC_FILE, APPLICATION_RESOURCE, CONNECTOR_RESOURCE, HEARTBEAT;
     }
 
     protected RequestType getRequestType(WrappedHttpServletRequest request) {
@@ -1137,6 +1148,8 @@ public abstract class AbstractApplicationServlet extends HttpServlet implements
             return RequestType.STATIC_FILE;
         } else if (ServletPortletHelper.isApplicationResourceRequest(request)) {
             return RequestType.APPLICATION_RESOURCE;
+        } else if (ServletPortletHelper.isHeartbeatRequest(request)) {
+            return RequestType.HEARTBEAT;
         }
         return RequestType.OTHER;
 
diff --git a/server/src/com/vaadin/terminal/gwt/server/AbstractCommunicationManager.java b/server/src/com/vaadin/terminal/gwt/server/AbstractCommunicationManager.java
index 00e65382cd..3099903454 100644
--- a/server/src/com/vaadin/terminal/gwt/server/AbstractCommunicationManager.java
+++ b/server/src/com/vaadin/terminal/gwt/server/AbstractCommunicationManager.java
@@ -87,6 +87,7 @@ import com.vaadin.terminal.Vaadin6Component;
 import com.vaadin.terminal.VariableOwner;
 import com.vaadin.terminal.WrappedRequest;
 import com.vaadin.terminal.WrappedResponse;
+import com.vaadin.terminal.gwt.client.ApplicationConnection;
 import com.vaadin.terminal.gwt.server.BootstrapHandler.BootstrapContext;
 import com.vaadin.terminal.gwt.server.ComponentSizeValidator.InvalidLayout;
 import com.vaadin.terminal.gwt.server.RpcManager.RpcInvocationException;
@@ -102,7 +103,7 @@ import com.vaadin.ui.Window;
  * This is a common base class for the server-side implementations of the
  * communication system between the client code (compiled with GWT into
  * JavaScript) and the server side components. Its client side counterpart is
- * {@link ApplicationConstants}.
+ * {@link ApplicationConnection}.
  * 
  * TODO Document better!
  */
@@ -577,6 +578,9 @@ public abstract class AbstractCommunicationManager implements Serializable {
                 return;
             }
 
+            // Keep the root alive
+            root.heartbeat();
+
             // Change all variables based on request parameters
             if (!handleVariables(request, response, callback, application, root)) {
 
@@ -2634,6 +2638,38 @@ public abstract class AbstractCommunicationManager implements Serializable {
 
     }
 
+    /**
+     * Handles a heartbeat request. Heartbeat requests are periodically sent by
+     * the client-side to inform the server that the root sending the heartbeat
+     * is still alive (the browser window is open, the connection is up) even
+     * when there are no UIDL requests for a prolonged period of time. Roots
+     * that do not receive either heartbeat or UIDL requests are eventually
+     * removed from the application and garbage collected.
+     * 
+     * @param request
+     * @param response
+     * @param application
+     * @throws IOException
+     */
+    public void handleHeartbeatRequest(WrappedRequest request,
+            WrappedResponse response, Application application)
+            throws IOException {
+        Root root = null;
+        try {
+            int rootId = Integer.parseInt(request
+                    .getParameter(ApplicationConstants.ROOT_ID_PARAMETER));
+            root = application.getRootById(rootId);
+        } catch (NumberFormatException nfe) {
+            // null-check below handles this as well
+        }
+        if (root != null) {
+            root.heartbeat();
+        } else {
+            response.sendError(HttpServletResponse.SC_NOT_FOUND,
+                    "Root not found");
+        }
+    }
+
     public StreamVariable getStreamVariable(String connectorId,
             String variableName) {
         Map<String, StreamVariable> map = pidToNameToStreamVariable
diff --git a/server/src/com/vaadin/terminal/gwt/server/ServletPortletHelper.java b/server/src/com/vaadin/terminal/gwt/server/ServletPortletHelper.java
index 200f9a9103..6911101920 100644
--- a/server/src/com/vaadin/terminal/gwt/server/ServletPortletHelper.java
+++ b/server/src/com/vaadin/terminal/gwt/server/ServletPortletHelper.java
@@ -9,7 +9,7 @@ import com.vaadin.terminal.WrappedRequest;
 import com.vaadin.ui.Root;
 
 /*
-  * Copyright 2011 Vaadin Ltd.
+ * Copyright 2011 Vaadin Ltd.
  * 
  * Licensed under the Apache License, Version 2.0 (the "License"); you may not
  * use this file except in compliance with the License. You may obtain a copy of
@@ -129,4 +129,9 @@ class ServletPortletHelper implements Serializable {
         return hasPathPrefix(request, ApplicationConstants.APP_REQUEST_PATH);
     }
 
+    public static boolean isHeartbeatRequest(WrappedRequest request) {
+        return hasPathPrefix(request,
+                ApplicationConstants.HEARTBEAT_REQUEST_PATH);
+    }
+
 }