Clear leaked database connections when closing tabs without explicity logging out of Galite applications. [APPS-02TI]

galite-core/src/main/kotlin/org/kopi/galite/visual/ui/vaadin/main/MainWindow.kt

@@ -38,7 +38,6 @@ import com.vaadin.flow.component.Key
 import com.vaadin.flow.component.KeyModifier
 import com.vaadin.flow.component.ShortcutEvent
 import com.vaadin.flow.component.Shortcuts
-import com.vaadin.flow.component.UI
 import com.vaadin.flow.component.contextmenu.MenuItem
 import com.vaadin.flow.component.dependency.CssImport
 import com.vaadin.flow.component.html.Div
@@ -104,7 +103,6 @@ class MainWindow(locale: Locale, val logo: String, val href: String, val applica
     addLinksListeners()
     Shortcuts.addShortcutListener(this, this::goToPreviousPage, Key.PAGE_UP, KeyModifier.of("Alt"))
     Shortcuts.addShortcutListener(this, this::goToNextPage, Key.PAGE_DOWN, KeyModifier.of("Alt"))
-    addBeforeUnloadListener()
     instance = this
   }
 
@@ -243,88 +241,6 @@ class MainWindow(locale: Locale, val logo: String, val href: String, val applica
     }
   }
 
-  /**
-   * Adds a detatch listener to be excecuted only when a window is closed or navigated away
-   */
-  fun addWindowDetachListener(onDetach: () -> Unit) {
-    addDetachListener {
-      isWindowActuallyClosing { isClosing ->
-        if (isClosing) {
-          println("The window is closing or navigating away.")
-          onDetach()
-        } else {
-          println("The window was refreshed.")
-        }
-      }
-    }
-  }
-
-  /**
-   * Determines if the window is actually closing (i.e., the user is closing a tab or
-   * navigating away) as opposed to simply refreshing the page.
-   *
-   * This method uses a `localStorage` flag, `pageReload`, that is set or removed by the
-   * `addBeforeUnloadListener` method. The logic works as follows:
-   *
-   * - If `pageReload` is found and set to `'true'`, it indicates that a page refresh
-   *   occurred. In this case, the method returns `false` to indicate that the window
-   *   is not actually closing.
-   * - If `pageReload` is not found, it suggests that the window is closing (either
-   *   a tab close or navigation away), so the method returns `true`.
-   *
-   * @param callback A lambda function to handle the result: `true` if the window is closing (not a refresh), `false` otherwise.
-   */
-  private fun isWindowActuallyClosing(callback: (Boolean) -> Unit) {
-    UI.getCurrent().page.executeJs("return localStorage.getItem('pageReload') === 'true';").then {
-      val isRefresh = it.asBoolean()
-
-      callback(!isRefresh)
-    }
-  }
-
-  /**
-   * Adds a JavaScript listener for the `beforeunload` event to detect when a page is
-   * refreshed or when a tab is being closed/navigated away from.
-   *
-   * This listener distinguishes between a page refresh (navigation type `1`) and other
-   * events such as closing the browser tab or navigating away. It uses `localStorage`
-   * to set a flag based on the detected action, which can be used server-side to infer
-   * user actions when combined with a Vaadin `DetachListener`.
-   *
-   * - On page refresh: A flag `pageReload` is set in the browser's `localStorage`.
-   * - On tab close or navigation away: The `pageReload` flag is removed from `localStorage`.
-   *
-   * Example Usage:
-   * This function is useful for determining whether to perform cleanup operations (like
-   * closing a database connection) only on tab close or navigation events but not on a refresh.
-   */
-  private fun addBeforeUnloadListener() {
-    UI.getCurrent().page.executeJs(
-      """
-        let isUnloading = false;
-
-        window.addEventListener('beforeunload', function(event) {
-            isUnloading = true;
-            // Save a flag to detect page reload
-            if (performance.navigation.type === 1) {
-                // Page refresh detected
-                localStorage.setItem('pageReload', 'true');
-            } else {
-                // Tab close or navigation away
-                localStorage.removeItem('pageReload');
-            }
-        });
-
-        // Use 'unload' event as a fallback for closing/navigating away cases
-        window.addEventListener('unload', function(event) {
-            if (!isUnloading) {
-                localStorage.removeItem('pageReload');
-            }
-        });
-        """
-    )
-  }
-
   /**
    * Adds a main window listener.
    * @param l the listener to be registered.

galite-core/src/main/kotlin/org/kopi/galite/visual/ui/vaadin/visual/VApplication.kt

@@ -1,6 +1,6 @@
 /*
- * Copyright (c) 2013-2022 kopiLeft Services SARL, Tunis TN
- * Copyright (c) 1990-2022 kopiRight Managed Solutions GmbH, Wien AT
+ * Copyright (c) 2013-2025 kopiLeft Services SARL, Tunis TN
+ * Copyright (c) 1990-2025 kopiRight Managed Solutions GmbH, Wien AT
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Lesser General Public
@@ -18,8 +18,12 @@
 package org.kopi.galite.visual.ui.vaadin.visual
 
 import java.sql.SQLException
+import java.time.LocalDateTime
 import java.util.Date
 import java.util.Locale
+import java.util.concurrent.CopyOnWriteArrayList
+
+import org.slf4j.LoggerFactory
 
 import com.vaadin.flow.component.AttachEvent
 import com.vaadin.flow.component.UI
@@ -33,6 +37,8 @@ import com.vaadin.flow.router.PreserveOnRefresh
 import com.vaadin.flow.server.AppShellRegistry
 import com.vaadin.flow.server.AppShellSettings
 import com.vaadin.flow.server.ServiceInitEvent
+import com.vaadin.flow.server.SessionDestroyEvent
+import com.vaadin.flow.server.SessionInitEvent
 import com.vaadin.flow.server.VaadinServiceInitListener
 import com.vaadin.flow.server.VaadinServlet
 import com.vaadin.flow.server.VaadinSession
@@ -252,10 +258,6 @@ abstract class VApplication(override val registry: Registry) : VerticalLayout(),
     mainWindow!!.setBookmarksMenu(DBookmarkMenu(menu!!))
     mainWindow!!.setWorkspaceContextItemMenu(DBookmarkMenu(menu!!))
     mainWindow!!.connectedUser = userName
-    mainWindow!!.addWindowDetachListener {
-      //closing DB connection if the UI is closed after 3 heartbeats
-      closeConnection()
-    }
   }
 
   fun remove(mainWindow: MainWindow?) {
@@ -341,6 +343,9 @@ abstract class VApplication(override val registry: Registry) : VerticalLayout(),
     if (dBConnection == null) {
       throw SQLException(MessageCode.getMessage("VIS-00054"))
     } else {
+      // Add initiated database connection to vaadin session attributes.
+      // This allows us to clean up / close opened database connections on session destroy event.
+      addConnectionToSession(dBConnection!!)
       // set query trace level
       setTraceLevel()
     }
@@ -400,6 +405,31 @@ abstract class VApplication(override val registry: Registry) : VerticalLayout(),
     }
   }
 
+  /**
+   * Add initiated connection on login to current vaadin session.
+   * This allows us to clean up / close opened connections on session destroy event.
+   *
+   * @param connection Database connection initiated on application login.
+   */
+  fun addConnectionToSession(connection: Connection) {
+    val session = VaadinSession.getCurrent()
+
+    session.lock()
+    try {
+      // Get the existing list, or create a new one if null
+      val connections = session.getAttribute("DB_CONNECTIONS") as? MutableList<Connection>
+        ?: CopyOnWriteArrayList<Connection>().also {
+          // CopyOnWriteArrayList is used to be thread-safe,
+          // since multiple tabs/requests may access the list concurrently.
+          session.setAttribute("DB_CONNECTIONS", it)
+        }
+      // Add the new connection to the session attribute.
+      connections.add(connection)
+    } finally {
+      session.unlock()
+    }
+  }
+
   /**
    * Attaches a window to this application.
    * @param window The window to be added.
@@ -667,6 +697,8 @@ class GaliteAppShellConfigurator: AppShellConfigurator {
 }
 
 class ApplicationServiceInitListener: VaadinServiceInitListener {
+  private val logger = LoggerFactory.getLogger("vaadin.session.lifecycle")
+
   override fun serviceInit(event: ServiceInitEvent) {
     val context  = event.source.context
     val appShellRegistry = AppShellRegistry.getInstance(context)
@@ -682,5 +714,51 @@ class ApplicationServiceInitListener: VaadinServiceInitListener {
       val loadingIndicatorConfiguration = uiInitEvent.ui.loadingIndicatorConfiguration
       loadingIndicatorConfiguration.firstDelay = 1000
     }
+
+    // Add logging when a new vaadin session is initiated.
+    event.source.addSessionInitListener(::onSessionInit)
+    // Close all database connections opened within the current vaadin session.
+    event.source.addSessionDestroyListener(::onSessionDestroy)
+  }
+
+  /**
+   * Trace the created session ID when a new vaadin session is initiated.
+   */
+  fun onSessionInit(event: SessionInitEvent) {
+    val session = event.session
+
+    logger.info("${LocalDateTime.now()} - New Session [ID : ${session.session.id}] is created.")
+  }
+
+  /**
+   * Close all database connections opened within the current vaadin session if not already closed.
+   */
+  fun onSessionDestroy(event: SessionDestroyEvent) {
+    val session = event.session
+
+    session.lock()
+    try {
+      val connections = session.getAttribute("DB_CONNECTIONS") as? List<Connection>
+
+      connections?.forEach { connection ->
+        try {
+          // Close all opened connections in the current vaadin session.
+          if (!connection.poolConnection.isClosed) {
+            connection.poolConnection.close()
+            logger.info("${LocalDateTime.now()} - DB connection ${connection.poolConnection} closed " +
+                            "for session [ID : ${session.session.id}].")
+          }
+        } catch (ex: Exception) {
+          logger.warn("${LocalDateTime.now()} - Failed to close connection ${connection.poolConnection} " +
+                          "for session [ID : ${session.session.id}]", ex)
+        }
+      }
+      // Clear the "DB_CONNECTIONS" attribute.
+      session.setAttribute("DB_CONNECTIONS", null)
+      // Session destroyed.
+      logger.info("${LocalDateTime.now()} - Session [ID : ${session.session.id}] is destroyed.")
+    } finally {
+      session.unlock()
+    }
   }
 }

galite-demo/galite-vaadin/src/main/webapp/WEB-INF/web.xml

@@ -50,6 +50,6 @@
     <url-pattern>/*</url-pattern>
   </servlet-mapping>
   <session-config>
-    <session-timeout>480</session-timeout>
+    <session-timeout>300</session-timeout>
   </session-config>
 </web-app>

gradle.properties

@@ -1,4 +1,4 @@
 org.gradle.jvmargs=-Xmx4g
 #
 group=org.kopi
-version=1.5.12
+version=1.5.12-02TI-SNAPSHOT