Support suspend timeout for long polling (#18550)

Change-Id: I1dc35f060b255baff4d28a815414836d4852218b

3 files changed, 64 insertions, 3 deletions

diff --git a/server/src/com/vaadin/server/Constants.java b/server/src/com/vaadin/server/Constants.java
index 5a0d852299..77a1a3134e 100644
--- a/server/src/com/vaadin/server/Constants.java
+++ b/server/src/com/vaadin/server/Constants.java
@@ -137,6 +137,7 @@ public interface Constants {
     static final String SERVLET_PARAMETER_LEGACY_PROPERTY_TOSTRING = "legacyPropertyToString";
     static final String SERVLET_PARAMETER_SYNC_ID_CHECK = "syncIdCheck";
     static final String SERVLET_PARAMETER_SENDURLSASPARAMETERS = "sendUrlsAsParameters";
+    static final String SERVLET_PARAMETER_PUSH_SUSPEND_TIMEOUT_LONGPOLLING = "pushLongPollingSuspendTimeout";
 
     // Configurable parameter names
     static final String PARAMETER_VAADIN_RESOURCES = "Resources";
diff --git a/server/src/com/vaadin/server/communication/PushHandler.java b/server/src/com/vaadin/server/communication/PushHandler.java
index 01077c3f86..994415a0b4 100644
--- a/server/src/com/vaadin/server/communication/PushHandler.java
+++ b/server/src/com/vaadin/server/communication/PushHandler.java
@@ -55,6 +55,8 @@ import elemental.json.JsonException;
  */
 public class PushHandler {
 
+    private int longPollingSuspendTimeout = -1;
+
     /**
      * Callback interface used internally to process an event with the
      * corresponding UI properly locked.
@@ -107,7 +109,7 @@ public class PushHandler {
                 return;
             }
 
-            resource.suspend();
+            suspend(resource);
 
             AtmospherePushConnection connection = getConnectionForUI(ui);
             assert (connection != null);
@@ -174,6 +176,21 @@ public class PushHandler {
     }
 
     /**
+     * Suspends the given resource
+     * 
+     * @since
+     * @param resource
+     *            the resource to suspend
+     */
+    protected void suspend(AtmosphereResource resource) {
+        if (resource.transport() == TRANSPORT.LONG_POLLING) {
+            resource.suspend(getLongPollingSuspendTimeout());
+        } else {
+            resource.suspend(-1);
+        }
+    }
+
+    /**
      * Find the UI for the atmosphere resource, lock it and invoke the callback.
      * 
      * @param resource
@@ -493,4 +510,26 @@ public class PushHandler {
                 resource.transport() == TRANSPORT.WEBSOCKET);
     }
 
+    /**
+     * Sets the timeout used for suspend calls when using long polling.
+     * 
+     * If you are using a proxy with a defined idle timeout, set the suspend
+     * timeout to a value smaller than the proxy timeout so that the server is
+     * aware of a reconnect taking place.
+     * 
+     * @param suspendTimeout
+     *            the timeout to use for suspended AtmosphereResources
+     */
+    public void setLongPollingSuspendTimeout(int longPollingSuspendTimeout) {
+        this.longPollingSuspendTimeout = longPollingSuspendTimeout;
+    }
+
+    /**
+     * Gets the timeout used for suspend calls when using long polling.
+     * 
+     * @return the timeout to use for suspended AtmosphereResources
+     */
+    public int getLongPollingSuspendTimeout() {
+        return longPollingSuspendTimeout;
+    }
 }
diff --git a/server/src/com/vaadin/server/communication/PushRequestHandler.java b/server/src/com/vaadin/server/communication/PushRequestHandler.java
index c01c74e5cd..c44fcd9ef3 100644
--- a/server/src/com/vaadin/server/communication/PushRequestHandler.java
+++ b/server/src/com/vaadin/server/communication/PushRequestHandler.java
@@ -77,7 +77,7 @@ public class PushRequestHandler implements RequestHandler,
         final ServletConfig vaadinServletConfig = service.getServlet()
                 .getServletConfig();
 
-        pushHandler = new PushHandler(service);
+        pushHandler = createPushHandler(service);
 
         atmosphere = getPreInitializedAtmosphere(vaadinServletConfig);
         if (atmosphere == null) {
@@ -100,7 +100,12 @@ public class PushRequestHandler implements RequestHandler,
                     "Using pre-initialized Atmosphere for servlet "
                             + vaadinServletConfig.getServletName());
         }
-
+        pushHandler
+                .setLongPollingSuspendTimeout(atmosphere
+                        .getAtmosphereConfig()
+                        .getInitParameter(
+                                com.vaadin.server.Constants.SERVLET_PARAMETER_PUSH_SUSPEND_TIMEOUT_LONGPOLLING,
+                                -1));
         for (AtmosphereHandlerWrapper handlerWrapper : atmosphere
                 .getAtmosphereHandlers().values()) {
             AtmosphereHandler handler = handlerWrapper.atmosphereHandler;
@@ -113,6 +118,22 @@ public class PushRequestHandler implements RequestHandler,
         }
     }
 
+    /**
+     * Creates a push handler for this request handler.
+     * <p>
+     * Create your own request handler and override this method if you want to
+     * customize the {@link PushHandler}, e.g. to dynamically decide the suspend
+     * timeout.
+     * 
+     * @since
+     * @param service
+     *            the vaadin service
+     * @return the push handler to use for this service
+     */
+    protected PushHandler createPushHandler(VaadinServletService service) {
+        return new PushHandler(service);
+    }
+
     private static final Logger getLogger() {
         return Logger.getLogger(PushRequestHandler.class.getName());
     }