IMAP Idle Timeout #176

providers/angus-mail/src/test/java/org/eclipse/angus/mail/imap/IdleTimeoutTest.java

@@ -0,0 +1,80 @@
+/*
+ * Copyright (c) 2025 Oracle and/or its affiliates. All rights reserved.
+ *
+ * This program and the accompanying materials are made available under the
+ * terms of the Eclipse Public License v. 2.0, which is available at
+ * http://www.eclipse.org/legal/epl-2.0.
+ *
+ * This Source Code may also be made available under the following Secondary
+ * Licenses when the conditions for such availability set forth in the
+ * Eclipse Public License v. 2.0 are satisfied: GNU General Public License,
+ * version 2 with the GNU Classpath Exception, which is available at
+ * https://www.gnu.org/software/classpath/license.html.
+ *
+ * SPDX-License-Identifier: EPL-2.0 OR GPL-2.0 WITH Classpath-exception-2.0
+ */
+
+package org.eclipse.angus.mail.imap;
+import java.util.Properties;
+import java.util.concurrent.Executor;
+import java.util.concurrent.Executors;
+
+import jakarta.mail.Folder;
+import jakarta.mail.Session;
+import jakarta.mail.Store;
+
+import org.eclipse.angus.mail.test.SingleThreadServer;
+import org.junit.Test;
+
+public class IdleTimeoutTest {
+
+    private static final long TIMEOUT = 3000; 
+    private final Executor executor = Executors.newCachedThreadPool();
+
+    @Test
+    public void testTimeout() throws Exception {
+        try (SingleThreadServer server = new SingleThreadServer()) {
+
+            // Predefine the server responses, so it is mocking an IMAP server
+
+            server.prepareResponse("A0 CAPABILITY\r\n",
+                    "* CAPABILITY IMAP4rev1 STARTTLS AUTH=PLAIN AUTH=LOGIN IDLE UIDPLUS\r\n" +
+                    "A0 OK CAPABILITY completed\r\n");
+
+            server.prepareResponse("A1 AUTHENTICATE PLAIN\r\n", "+\r\n");
+            server.prepareResponse("AHVzZXJAdGVzdC5jb20AMTIzNA==\r\n",
+                    "A1 OK AUTHENTICATE completed\r\n");
+
+            server.prepareResponse("A2 CAPABILITY\r\n",
+                    "* CAPABILITY IMAP4rev1 IDLE UIDPLUS\r\n" +
+                    "A2 OK CAPABILITY completed\r\n");
+
+            server.prepareResponse("A3 SELECT INBOX\r\n",
+                    "* 0 EXISTS\r\n" +
+                    "* FLAGS (\\Answered \\Flagged \\Deleted \\Seen \\Draft)\r\n" +
+                    "A3 OK [READ-WRITE] SELECT completed\r\n");
+
+            server.prepareResponse("A4 IDLE\r\n", "+ idling\r\n");
+
+            server.start();
+            Properties properties = new Properties();
+            properties.setProperty("mail.imap.host", "localhost");
+            properties.setProperty("mail.imap.port", Integer.toString(server.getPort()));
+            // We want to verify what happens when client gets SocketTimeoutException
+            properties.setProperty("mail.imap.timeout", Long.toString(TIMEOUT));
+            // Required to IDLE
+            properties.setProperty("mail.imap.usesocketchannels", "true");
+            Session session = Session.getDefaultInstance(properties);
+            Store store = session.getStore("imap");
+            store.connect("user@test.com", "1234");
+            IdleManager im = new IdleManager(session, executor);
+            Folder folder = store.getFolder("INBOX");
+            folder.open(Folder.READ_WRITE);
+
+            im.watch(folder);
+            // Client is going to get the SocketTimeoutException after TIMEOUT
+            Thread.sleep(9999999L);
+        }
+    }
+
+}

providers/angus-mail/src/test/java/org/eclipse/angus/mail/test/SingleThreadServer.java

@@ -0,0 +1,115 @@
+/*
+ * Copyright (c) 2025 Oracle and/or its affiliates. All rights reserved.
+ *
+ * This program and the accompanying materials are made available under the
+ * terms of the Eclipse Public License v. 2.0, which is available at
+ * http://www.eclipse.org/legal/epl-2.0.
+ *
+ * This Source Code may also be made available under the following Secondary
+ * Licenses when the conditions for such availability set forth in the
+ * Eclipse Public License v. 2.0 are satisfied: GNU General Public License,
+ * version 2 with the GNU Classpath Exception, which is available at
+ * https://www.gnu.org/software/classpath/license.html.
+ *
+ * SPDX-License-Identifier: EPL-2.0 OR GPL-2.0 WITH Classpath-exception-2.0
+ */
+
+package org.eclipse.angus.mail.test;
+
+import java.io.Closeable;
+import java.io.IOException;
+import java.io.OutputStream;
+import java.io.UncheckedIOException;
+import java.net.ServerSocket;
+import java.net.Socket;
+import java.util.HashMap;
+import java.util.Map;
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Executors;
+
+public class SingleThreadServer implements AutoCloseable {
+
+    private int port;
+    private ServerSocket server;
+    private Socket serverSocket;
+    private ExecutorService executor;
+    private volatile boolean running;
+    private Map<String, String> predefinedResponses = new HashMap<>();
+
+    public void start() {
+        try {
+            executor = Executors.newSingleThreadExecutor();
+            server = new ServerSocket(0);
+            port = server.getLocalPort();
+            executor.submit(() -> {
+                try {
+                    serverSocket = server.accept();
+                    System.out.println("Connected to " + serverSocket.getRemoteSocketAddress());
+                    System.out.println("Server > * OK IMAP4rev1 Service Ready\r\n");
+                    writeInServer("* OK IMAP4rev1 Service Ready\r\n");
+                    running = true;
+                    byte[] buffer = new byte[1024];
+                    int bytesRead;
+                    while (running && (bytesRead = serverSocket.getInputStream().read(buffer)) != -1) {
+                        String data = new String(buffer, 0, bytesRead);
+                        System.out.println("Client > " + data);
+                        String response = predefinedResponses.get(data);
+                        if (response != null) {
+                            System.out.println("Server > " + response);
+                            writeInServer(response);
+                        }
+                    }
+                } catch (IOException e1) {
+                    throw new UncheckedIOException(e1);
+                }
+            });
+        } catch (IOException e) {
+            throw new UncheckedIOException(e);
+        }
+    }
+
+    public void prepareResponse(String clientSends, String serverResponds) {
+        predefinedResponses.put(clientSends, serverResponds);
+    }
+
+    public void stop() {
+        if (running) {
+            running = false;
+            close(serverSocket);
+            serverSocket = null;
+            close(server);
+            server = null;
+            if (executor != null) {
+                executor.shutdown();
+                executor = null;
+            }
+        }
+    }
+
+    private void close(Closeable c) {
+        if (c != null) {
+            try {
+                c.close();
+            } catch (IOException e) {}
+        }
+    }
+
+    private void writeInServer(String data) {
+        try {
+            OutputStream out = serverSocket.getOutputStream();
+            out.write(data.getBytes());
+            out.flush();
+        } catch (IOException e) {
+            throw new UncheckedIOException(e);
+        }
+    }
+
+    public int getPort() {
+        return port;
+    }
+
+    @Override
+    public void close() throws Exception {
+        stop();
+    }
+}

providers/imap/src/main/java/org/eclipse/angus/mail/imap/IMAPFolder.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 1997, 2023 Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 1997, 2025 Oracle and/or its affiliates. All rights reserved.
  *
  * This program and the accompanying materials are made available under the
  * terms of the Eclipse Public License v. 2.0, which is available at
@@ -3262,7 +3262,9 @@ boolean handleIdle(boolean once) throws MessagingException {
                     if (r.isBYE() && r.isSynthetic() && idleState == IDLE) {
                         /*
                          * If it was a timeout and no bytes were transferred
-                         * we ignore it and go back and read again.
+                         * we abort IDLE and request IDLE again,
+                         * so the server can continue pushing.
+                         *
                          * If the I/O was otherwise interrupted, and no
                          * bytes were transferred, we take it as a request
                          * to abort the IDLE.
@@ -3272,9 +3274,13 @@ boolean handleIdle(boolean once) throws MessagingException {
                                 ((InterruptedIOException) ex).
                                         bytesTransferred == 0) {
                             if (ex instanceof SocketTimeoutException) {
-                                logger.finest(
-                                        "handleIdle: ignoring socket timeout");
-                                r = null;    // repeat do/while loop
+                                logger.finest("handleIdle: socket timeout");
+                                // Next aborts and read responses
+                                idleAbortWait();
+                                // Reissue the IDLE
+                                if (startIdle(idleManager)) {
+                                    r = null;    // repeat do/while loop
+                                }
                             } else {
                                 logger.finest("handleIdle: interrupting IDLE");
                                 IdleManager im = idleManager;