Add support for passive connection lost checking

src/main/java/org/java_websocket/AbstractWebSocket.java

@@ -32,6 +32,7 @@
 import java.util.concurrent.ScheduledFuture;
 import java.util.concurrent.TimeUnit;
 import org.java_websocket.framing.CloseFrame;
+import org.java_websocket.framing.Framedata;
 import org.java_websocket.util.NamedThreadFactory;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
@@ -83,6 +84,13 @@ public abstract class AbstractWebSocket extends WebSocketAdapter {
    */
   private long connectionLostTimeout = TimeUnit.SECONDS.toNanos(60);
 
+  /**
+   * Attribute for the passive lost connection check
+   *
+   * @since 1.5.5
+   */
+  private boolean connectionLostCheckPassive = false;
+
   /**
    * Attribute to keep track if the WebSocket Server/Client is running/connected
    *
@@ -107,6 +115,16 @@ public int getConnectionLostTimeout() {
     }
   }
 
+  /**
+   * Tests if connection lost check is passive
+   *
+   * @return a boolean indicating whether or not the connection lost check is passive
+   * @since 1.5.5
+   */
+  public boolean isConnectionLostCheckPassive() {
+    return connectionLostCheckPassive;
+  }
+
   /**
    * Setter for the interval checking for lost connections A value lower or equal 0 results in the
    * check to be deactivated
@@ -115,8 +133,21 @@ public int getConnectionLostTimeout() {
    * @since 1.3.4
    */
   public void setConnectionLostTimeout(int connectionLostTimeout) {
+    setConnectionLostTimeout(connectionLostTimeout, false);
+  }
+
+  /**
+   * Setter for the interval checking for lost connections A value lower or equal 0 results in the
+   * check to be deactivated
+   *
+   * @param connectionLostTimeout the interval in seconds
+   * @param passive true for passive lost connection checks, false for active checks
+   * @since 1.5.5
+   */
+  public void setConnectionLostTimeout(int connectionLostTimeout, boolean passive) {
     synchronized (syncConnectionLost) {
       this.connectionLostTimeout = TimeUnit.SECONDS.toNanos(connectionLostTimeout);
+      this.connectionLostCheckPassive = passive;
       if (this.connectionLostTimeout <= 0) {
         log.trace("Connection lost timer stopped");
         cancelConnectionLostTimer();
@@ -228,11 +259,12 @@ private void executeConnectionLostDetection(WebSocket webSocket, long minimumPon
     }
     WebSocketImpl webSocketImpl = (WebSocketImpl) webSocket;
     if (webSocketImpl.getLastPong() < minimumPongTime) {
-      log.trace("Closing connection due to no pong received: {}", webSocketImpl);
+      log.trace("Closing connection due to no {} received: {}", connectionLostCheckPassive ? "ping" : "pong", webSocketImpl);
       webSocketImpl.closeConnection(CloseFrame.ABNORMAL_CLOSE,
-          "The connection was closed because the other endpoint did not respond with a pong in time. For more information check: https://github.com/TooTallNate/Java-WebSocket/wiki/Lost-connection-detection");
+          "The connection was closed because the other endpoint did not " + (connectionLostCheckPassive ? "send a ping" : "respond with a pong") + " in time. " +
+          "For more information check: https://github.com/TooTallNate/Java-WebSocket/wiki/Lost-connection-detection");
     } else {
-      if (webSocketImpl.isOpen()) {
+      if (webSocketImpl.isOpen() && !connectionLostCheckPassive) {
         webSocketImpl.sendPing();
       } else {
         log.trace("Trying to ping a non open connection: {}", webSocketImpl);
@@ -308,4 +340,19 @@ public void setReuseAddr(boolean reuseAddr) {
     this.reuseAddr = reuseAddr;
   }
 
+  /**
+   * This overriden implementation will additionally update the last pong time in case
+   * connection lost checks are passive.
+   *
+   * @see org.java_websocket.WebSocketListener#onWebsocketPing(WebSocket, Framedata)
+   */
+  @Override
+  public void onWebsocketPing(WebSocket conn, Framedata f) {
+    super.onWebsocketPing(conn, f);
+    if (connectionLostCheckPassive && conn instanceof WebSocketImpl) {
+      WebSocketImpl webSocketImpl = (WebSocketImpl) conn;
+      webSocketImpl.updateLastPong();
+    }
+  }
+
 }

src/main/java/org/java_websocket/WebSocketImpl.java

@@ -428,7 +428,11 @@ private void decodeFrames(ByteBuffer socketBuffer) {
    * @param exception the InvalidDataException causing this problem
    */
   private void closeConnectionDueToWrongHandshake(InvalidDataException exception) {
-    write(generateHttpResponseDueToError(404));
+    if (exception.getHttpErrorCode() != null) {
+      write(generateHttpResponseDueToError(exception.getHttpErrorCode()));
+    } else {
+      write(generateHttpResponseDueToError(404));
+    }
     flushAndClose(exception.getCloseCode(), exception.getMessage(), false);
   }
 
@@ -451,6 +455,9 @@ private void closeConnectionDueToInternalServerError(RuntimeException exception)
   private ByteBuffer generateHttpResponseDueToError(int errorCode) {
     String errorCodeDescription;
     switch (errorCode) {
+      case 401:
+        errorCodeDescription = "401 Authorization Required";
+        break;
       case 404:
         errorCodeDescription = "404 WebSocket Upgrade Failure";
         break;

src/main/java/org/java_websocket/exceptions/InvalidDataException.java

@@ -40,6 +40,8 @@ public class InvalidDataException extends Exception {
    */
   private final int closecode;
 
+  private Integer httpErrorCode;
+
   /**
    * constructor for a InvalidDataException
    *
@@ -49,6 +51,17 @@ public InvalidDataException(int closecode) {
     this.closecode = closecode;
   }
 
+  /**
+   * constructor for a InvalidDataException
+   *
+   * @param closecode the closecode which will be returned
+   * @param httpErrorCode the httpErrorCode which will be returned.
+   */
+  public InvalidDataException(int closecode, int httpErrorCode) {
+    this.closecode = closecode;
+    this.httpErrorCode = httpErrorCode;
+  }
+
   /**
    * constructor for a InvalidDataException.
    *
@@ -60,6 +73,19 @@ public InvalidDataException(int closecode, String s) {
     this.closecode = closecode;
   }
 
+  /**
+   * constructor for a InvalidDataException.
+   *
+   * @param closecode the closecode which will be returned.
+   * @param s         the detail message.
+   * @param httpErrorCode the httpErrorCode which will be returned.
+   */
+  public InvalidDataException(int closecode, String s, int httpErrorCode) {
+    super(s);
+    this.closecode = closecode;
+    this.httpErrorCode = httpErrorCode;
+  }
+
   /**
    * constructor for a InvalidDataException.
    *
@@ -92,4 +118,13 @@ public int getCloseCode() {
     return closecode;
   }
 
+  /**
+   * Getter httpErrorCode
+   *
+   * @return the httpErrorCode
+   */
+  public Integer getHttpErrorCode() {
+    return httpErrorCode;
+  }
+
 }