Send close frame on channel close, when this frame was not send manually (#9745)

Motivation:
By default CloseWebSocketFrames are handled automatically.
However I need manually manage their sending both on client- and on server-sides.

Modification:
Send close frame on channel close automatically, when it was not send before explicitly.

Result:
No more messages like "Connection closed by remote peer" for normal close flows.

codec-http/src/main/java/io/netty/handler/codec/http/websocketx/WebSocketClientProtocolConfig.java

@@ -30,8 +30,8 @@ import static io.netty.util.internal.ObjectUtil.checkPositive;
 public final class WebSocketClientProtocolConfig {
 
     static final WebSocketClientProtocolConfig DEFAULT = new WebSocketClientProtocolConfig(
-        URI.create("https://localhost/"), null, WebSocketVersion.V13, false,
+        URI.create("https://localhost/"), null, WebSocketVersion.V13, false, EmptyHttpHeaders.INSTANCE,
-        EmptyHttpHeaders.INSTANCE, 65536, true, false, true, true, 10000L, -1, false);
+        65536, true, false, true, WebSocketCloseStatus.NORMAL_CLOSURE, true, 10000L, -1, false);
 
     private final URI webSocketUri;
     private final String subprotocol;
@@ -42,6 +42,7 @@ public final class WebSocketClientProtocolConfig {
     private final boolean performMasking;
     private final boolean allowMaskMismatch;
     private final boolean handleCloseFrames;
+    private final WebSocketCloseStatus sendCloseFrame;
     private final boolean dropPongFrames;
     private final long handshakeTimeoutMillis;
     private final long forceCloseTimeoutMillis;
@@ -57,6 +58,7 @@ public final class WebSocketClientProtocolConfig {
         boolean performMasking,
         boolean allowMaskMismatch,
         boolean handleCloseFrames,
+        WebSocketCloseStatus sendCloseFrame,
         boolean dropPongFrames,
         long handshakeTimeoutMillis,
         long forceCloseTimeoutMillis,
@@ -72,6 +74,7 @@ public final class WebSocketClientProtocolConfig {
         this.allowMaskMismatch = allowMaskMismatch;
         this.forceCloseTimeoutMillis = forceCloseTimeoutMillis;
         this.handleCloseFrames = handleCloseFrames;
+        this.sendCloseFrame = sendCloseFrame;
         this.dropPongFrames = dropPongFrames;
         this.handshakeTimeoutMillis = checkPositive(handshakeTimeoutMillis, "handshakeTimeoutMillis");
         this.absoluteUpgradeUrl = absoluteUpgradeUrl;
@@ -113,6 +116,10 @@ public final class WebSocketClientProtocolConfig {
         return handleCloseFrames;
     }
 
+    public WebSocketCloseStatus sendCloseFrame() {
+        return sendCloseFrame;
+    }
+
     public boolean dropPongFrames() {
         return dropPongFrames;
     }
@@ -141,6 +148,7 @@ public final class WebSocketClientProtocolConfig {
             ", performMasking=" + performMasking +
             ", allowMaskMismatch=" + allowMaskMismatch +
             ", handleCloseFrames=" + handleCloseFrames +
+            ", sendCloseFrame=" + sendCloseFrame +
             ", dropPongFrames=" + dropPongFrames +
             ", handshakeTimeoutMillis=" + handshakeTimeoutMillis +
             ", forceCloseTimeoutMillis=" + forceCloseTimeoutMillis +
@@ -166,6 +174,7 @@ public final class WebSocketClientProtocolConfig {
         private boolean performMasking;
         private boolean allowMaskMismatch;
         private boolean handleCloseFrames;
+        private WebSocketCloseStatus sendCloseFrame;
         private boolean dropPongFrames;
         private long handshakeTimeoutMillis;
         private long forceCloseTimeoutMillis;
@@ -174,19 +183,20 @@ public final class WebSocketClientProtocolConfig {
         private Builder(WebSocketClientProtocolConfig clientConfig) {
             ObjectUtil.checkNotNull(clientConfig, "clientConfig");
 
-            this.webSocketUri = clientConfig.webSocketUri();
+            webSocketUri = clientConfig.webSocketUri();
-            this.subprotocol = clientConfig.subprotocol();
+            subprotocol = clientConfig.subprotocol();
-            this.version = clientConfig.version();
+            version = clientConfig.version();
-            this.allowExtensions = clientConfig.allowExtensions();
+            allowExtensions = clientConfig.allowExtensions();
-            this.customHeaders = clientConfig.customHeaders();
+            customHeaders = clientConfig.customHeaders();
-            this.maxFramePayloadLength = clientConfig.maxFramePayloadLength();
+            maxFramePayloadLength = clientConfig.maxFramePayloadLength();
-            this.performMasking = clientConfig.performMasking();
+            performMasking = clientConfig.performMasking();
-            this.allowMaskMismatch = clientConfig.allowMaskMismatch();
+            allowMaskMismatch = clientConfig.allowMaskMismatch();
-            this.handleCloseFrames = clientConfig.handleCloseFrames();
+            handleCloseFrames = clientConfig.handleCloseFrames();
-            this.dropPongFrames = clientConfig.dropPongFrames();
+            sendCloseFrame = clientConfig.sendCloseFrame();
-            this.handshakeTimeoutMillis = clientConfig.handshakeTimeoutMillis();
+            dropPongFrames = clientConfig.dropPongFrames();
-            this.forceCloseTimeoutMillis = clientConfig.forceCloseTimeoutMillis();
+            handshakeTimeoutMillis = clientConfig.handshakeTimeoutMillis();
-            this.absoluteUpgradeUrl = clientConfig.absoluteUpgradeUrl();
+            forceCloseTimeoutMillis = clientConfig.forceCloseTimeoutMillis();
+            absoluteUpgradeUrl = clientConfig.absoluteUpgradeUrl();
         }
 
         /**
@@ -272,6 +282,14 @@ public final class WebSocketClientProtocolConfig {
             return this;
         }
 
+        /**
+         * Close frame to send, when close frame was not send manually. Or {@code null} to disable proper close.
+         */
+        public Builder sendCloseFrame(WebSocketCloseStatus sendCloseFrame) {
+            this.sendCloseFrame = sendCloseFrame;
+            return this;
+        }
+
         /**
          * {@code true} if pong frames should not be forwarded
          */
@@ -319,6 +337,7 @@ public final class WebSocketClientProtocolConfig {
                 performMasking,
                 allowMaskMismatch,
                 handleCloseFrames,
+                sendCloseFrame,
                 dropPongFrames,
                 handshakeTimeoutMillis,
                 forceCloseTimeoutMillis,

codec-http/src/main/java/io/netty/handler/codec/http/websocketx/WebSocketClientProtocolHandler.java

@@ -42,8 +42,7 @@ import static io.netty.util.internal.ObjectUtil.*;
  */
 public class WebSocketClientProtocolHandler extends WebSocketProtocolHandler {
     private final WebSocketClientHandshaker handshaker;
-    private final boolean handleCloseFrames;
+    private final WebSocketClientProtocolConfig clientConfig;
-    private final long handshakeTimeoutMillis;
 
     /**
      * Returns the used handshaker
@@ -92,8 +91,7 @@ public class WebSocketClientProtocolHandler extends WebSocketProtocolHandler {
             clientConfig.forceCloseTimeoutMillis(),
             clientConfig.absoluteUpgradeUrl()
         );
-        this.handleCloseFrames = clientConfig.handleCloseFrames();
+        this.clientConfig = clientConfig;
-        this.handshakeTimeoutMillis = clientConfig.handshakeTimeoutMillis();
     }
 
     /**
@@ -327,8 +325,10 @@ public class WebSocketClientProtocolHandler extends WebSocketProtocolHandler {
                                           boolean dropPongFrames, long handshakeTimeoutMillis) {
         super(dropPongFrames);
         this.handshaker = handshaker;
-        this.handleCloseFrames = handleCloseFrames;
+        this.clientConfig = WebSocketClientProtocolConfig.newBuilder()
-        this.handshakeTimeoutMillis = checkPositive(handshakeTimeoutMillis, "handshakeTimeoutMillis");
+            .handleCloseFrames(handleCloseFrames)
+            .handshakeTimeoutMillis(handshakeTimeoutMillis)
+            .build();
     }
 
     /**
@@ -358,7 +358,7 @@ public class WebSocketClientProtocolHandler extends WebSocketProtocolHandler {
 
     @Override
     protected void decode(ChannelHandlerContext ctx, WebSocketFrame frame, List<Object> out) throws Exception {
-        if (handleCloseFrames && frame instanceof CloseWebSocketFrame) {
+        if (clientConfig.handleCloseFrames() && frame instanceof CloseWebSocketFrame) {
             ctx.close();
             return;
         }
@@ -371,12 +371,16 @@ public class WebSocketClientProtocolHandler extends WebSocketProtocolHandler {
         if (cp.get(WebSocketClientProtocolHandshakeHandler.class) == null) {
             // Add the WebSocketClientProtocolHandshakeHandler before this one.
             ctx.pipeline().addBefore(ctx.name(), WebSocketClientProtocolHandshakeHandler.class.getName(),
-                                     new WebSocketClientProtocolHandshakeHandler(handshaker, handshakeTimeoutMillis));
+                new WebSocketClientProtocolHandshakeHandler(handshaker, clientConfig.handshakeTimeoutMillis()));
         }
         if (cp.get(Utf8FrameValidator.class) == null) {
             // Add the UFT8 checking before this one.
             ctx.pipeline().addBefore(ctx.name(), Utf8FrameValidator.class.getName(),
                     new Utf8FrameValidator());
         }
+        if (clientConfig.sendCloseFrame() != null) {
+            cp.addBefore(ctx.name(), WebSocketCloseFrameHandler.class.getName(),
+                new WebSocketCloseFrameHandler(clientConfig.sendCloseFrame(), clientConfig.forceCloseTimeoutMillis()));
+        }
     }
 }

codec-http/src/main/java/io/netty/handler/codec/http/websocketx/WebSocketCloseFrameHandler.java

@@ -0,0 +1,97 @@
+/*
+ * Copyright 2019 The Netty Project
+ *
+ * The Netty Project licenses this file to you 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 the License at:
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations
+ * under the License.
+ */
+package io.netty.handler.codec.http.websocketx;
+
+import io.netty.channel.ChannelFuture;
+import io.netty.channel.ChannelFutureListener;
+import io.netty.channel.ChannelHandlerContext;
+import io.netty.channel.ChannelOutboundHandlerAdapter;
+import io.netty.channel.ChannelPromise;
+import io.netty.util.ReferenceCountUtil;
+import io.netty.util.concurrent.ScheduledFuture;
+import io.netty.util.internal.ObjectUtil;
+
+import java.nio.channels.ClosedChannelException;
+import java.util.concurrent.TimeUnit;
+
+/**
+ * Send {@link CloseWebSocketFrame} message on channel close, if close frame was not sent before.
+ */
+final class WebSocketCloseFrameHandler extends ChannelOutboundHandlerAdapter {
+    private final WebSocketCloseStatus closeStatus;
+    private final long forceCloseTimeoutMillis;
+    private ChannelPromise closeSent;
+
+    WebSocketCloseFrameHandler(WebSocketCloseStatus closeStatus, long forceCloseTimeoutMillis) {
+        this.closeStatus = ObjectUtil.checkNotNull(closeStatus, "closeStatus");
+        this.forceCloseTimeoutMillis = forceCloseTimeoutMillis;
+    }
+
+    @Override
+    public void close(final ChannelHandlerContext ctx, final ChannelPromise promise) throws Exception {
+        if (!ctx.channel().isActive()) {
+            ctx.close(promise);
+            return;
+        }
+        if (closeSent == null) {
+            write(ctx, new CloseWebSocketFrame(closeStatus), ctx.newPromise());
+        }
+        flush(ctx);
+        applyCloseSentTimeout(ctx);
+        closeSent.addListener(new ChannelFutureListener() {
+            @Override
+            public void operationComplete(ChannelFuture future) {
+                ctx.close(promise);
+            }
+        });
+    }
+
+    @Override
+    public void write(final ChannelHandlerContext ctx, Object msg, ChannelPromise promise) throws Exception {
+        if (closeSent != null) {
+            ReferenceCountUtil.release(msg);
+            promise.setFailure(new ClosedChannelException());
+            return;
+        }
+        if (msg instanceof CloseWebSocketFrame) {
+            promise = promise.unvoid();
+            closeSent = promise;
+        }
+        super.write(ctx, msg, promise);
+    }
+
+    private void applyCloseSentTimeout(ChannelHandlerContext ctx) {
+        if (closeSent.isDone() || forceCloseTimeoutMillis < 0) {
+            return;
+        }
+
+        final ScheduledFuture<?> timeoutTask = ctx.executor().schedule(new Runnable() {
+            @Override
+            public void run() {
+                if (!closeSent.isDone()) {
+                    closeSent.tryFailure(new WebSocketHandshakeException("send close frame timed out"));
+                }
+            }
+        }, forceCloseTimeoutMillis, TimeUnit.MILLISECONDS);
+
+        closeSent.addListener(new ChannelFutureListener() {
+            @Override
+            public void operationComplete(ChannelFuture future) {
+                timeoutTask.cancel(false);
+            }
+        });
+    }
+}

codec-http/src/main/java/io/netty/handler/codec/http/websocketx/WebSocketServerProtocolConfig.java

@@ -25,14 +25,16 @@ import static io.netty.util.internal.ObjectUtil.checkPositive;
  */
 public final class WebSocketServerProtocolConfig {
 
-    static final WebSocketServerProtocolConfig DEFAULT =
+    static final WebSocketServerProtocolConfig DEFAULT = new WebSocketServerProtocolConfig(
-        new WebSocketServerProtocolConfig("/", null, false, 10000L, true, true, WebSocketDecoderConfig.DEFAULT);
+        "/", null, false, 10000L, 0, true, WebSocketCloseStatus.NORMAL_CLOSURE, true, WebSocketDecoderConfig.DEFAULT);
 
     private final String websocketPath;
     private final String subprotocols;
     private final boolean checkStartsWith;
     private final long handshakeTimeoutMillis;
+    private final long forceCloseTimeoutMillis;
     private final boolean handleCloseFrames;
+    private final WebSocketCloseStatus sendCloseFrame;
     private final boolean dropPongFrames;
     private final WebSocketDecoderConfig decoderConfig;
 
@@ -41,7 +43,9 @@ public final class WebSocketServerProtocolConfig {
         String subprotocols,
         boolean checkStartsWith,
         long handshakeTimeoutMillis,
+        long forceCloseTimeoutMillis,
         boolean handleCloseFrames,
+        WebSocketCloseStatus sendCloseFrame,
         boolean dropPongFrames,
         WebSocketDecoderConfig decoderConfig
     ) {
@@ -49,7 +53,9 @@ public final class WebSocketServerProtocolConfig {
         this.subprotocols = subprotocols;
         this.checkStartsWith = checkStartsWith;
         this.handshakeTimeoutMillis = checkPositive(handshakeTimeoutMillis, "handshakeTimeoutMillis");
+        this.forceCloseTimeoutMillis = forceCloseTimeoutMillis;
         this.handleCloseFrames = handleCloseFrames;
+        this.sendCloseFrame = sendCloseFrame;
         this.dropPongFrames = dropPongFrames;
         this.decoderConfig = decoderConfig == null ? WebSocketDecoderConfig.DEFAULT : decoderConfig;
     }
@@ -70,10 +76,18 @@ public final class WebSocketServerProtocolConfig {
         return handshakeTimeoutMillis;
     }
 
+    public long forceCloseTimeoutMillis() {
+        return forceCloseTimeoutMillis;
+    }
+
     public boolean handleCloseFrames() {
         return handleCloseFrames;
     }
 
+    public WebSocketCloseStatus sendCloseFrame() {
+        return sendCloseFrame;
+    }
+
     public boolean dropPongFrames() {
         return dropPongFrames;
     }
@@ -89,7 +103,9 @@ public final class WebSocketServerProtocolConfig {
             ", subprotocols=" + subprotocols +
             ", checkStartsWith=" + checkStartsWith +
             ", handshakeTimeoutMillis=" + handshakeTimeoutMillis +
+            ", forceCloseTimeoutMillis=" + forceCloseTimeoutMillis +
             ", handleCloseFrames=" + handleCloseFrames +
+            ", sendCloseFrame=" + sendCloseFrame +
             ", dropPongFrames=" + dropPongFrames +
             ", decoderConfig=" + decoderConfig +
             "}";
@@ -108,7 +124,9 @@ public final class WebSocketServerProtocolConfig {
         private String subprotocols;
         private boolean checkStartsWith;
         private long handshakeTimeoutMillis;
+        private long forceCloseTimeoutMillis;
         private boolean handleCloseFrames;
+        private WebSocketCloseStatus sendCloseFrame;
         private boolean dropPongFrames;
         private WebSocketDecoderConfig decoderConfig;
         private WebSocketDecoderConfig.Builder decoderConfigBuilder;
@@ -119,7 +137,9 @@ public final class WebSocketServerProtocolConfig {
             subprotocols = serverConfig.subprotocols();
             checkStartsWith = serverConfig.checkStartsWith();
             handshakeTimeoutMillis = serverConfig.handshakeTimeoutMillis();
+            forceCloseTimeoutMillis = serverConfig.forceCloseTimeoutMillis();
             handleCloseFrames = serverConfig.handleCloseFrames();
+            sendCloseFrame = serverConfig.sendCloseFrame();
             dropPongFrames = serverConfig.dropPongFrames();
             decoderConfig = serverConfig.decoderConfig();
         }
@@ -158,6 +178,14 @@ public final class WebSocketServerProtocolConfig {
             return this;
         }
 
+        /**
+         * Close the connection if it was not closed by the client after timeout specified
+         */
+        public Builder forceCloseTimeoutMillis(long forceCloseTimeoutMillis) {
+            this.forceCloseTimeoutMillis = forceCloseTimeoutMillis;
+            return this;
+        }
+
         /**
          * {@code true} if close frames should not be forwarded and just close the channel
          */
@@ -166,6 +194,14 @@ public final class WebSocketServerProtocolConfig {
             return this;
         }
 
+        /**
+         * Close frame to send, when close frame was not send manually. Or {@code null} to disable proper close.
+         */
+        public Builder sendCloseFrame(WebSocketCloseStatus sendCloseFrame) {
+            this.sendCloseFrame = sendCloseFrame;
+            return this;
+        }
+
         /**
          * {@code true} if pong frames should not be forwarded
          */
@@ -229,7 +265,9 @@ public final class WebSocketServerProtocolConfig {
                 subprotocols,
                 checkStartsWith,
                 handshakeTimeoutMillis,
+                forceCloseTimeoutMillis,
                 handleCloseFrames,
+                sendCloseFrame,
                 dropPongFrames,
                 decoderConfigBuilder == null ? decoderConfig : decoderConfigBuilder.build()
             );

codec-http/src/main/java/io/netty/handler/codec/http/websocketx/WebSocketServerProtocolHandler.java

@@ -228,6 +228,10 @@ public class WebSocketServerProtocolHandler extends WebSocketProtocolHandler {
             cp.addBefore(ctx.name(), Utf8FrameValidator.class.getName(),
                     new Utf8FrameValidator());
         }
+        if (serverConfig.sendCloseFrame() != null) {
+            cp.addBefore(ctx.name(), WebSocketCloseFrameHandler.class.getName(),
+                new WebSocketCloseFrameHandler(serverConfig.sendCloseFrame(), serverConfig.forceCloseTimeoutMillis()));
+        }
     }
 
     @Override

codec-http/src/test/java/io/netty/handler/codec/http/websocketx/WebSocket08EncoderDecoderTest.java

@@ -78,6 +78,9 @@ public class WebSocket08EncoderDecoderTest {
         Assert.assertEquals(errorMessage, response.reasonText());
         response.release();
 
+        Assert.assertFalse(inChannel.finish());
+        Assert.assertFalse(outChannel.finish());
+
         // Without auto-close
         config = WebSocketDecoderConfig.newBuilder()
             .maxFramePayloadLength(maxPayloadLength)
@@ -91,10 +94,11 @@ public class WebSocket08EncoderDecoderTest {
         response = inChannel.readOutbound();
         Assert.assertNull(response);
 
-        // Release test data
-        binTestData.release();
         Assert.assertFalse(inChannel.finish());
         Assert.assertFalse(outChannel.finish());
+
+        // Release test data
+        binTestData.release();
     }
 
     private void executeProtocolViolationTest(EmbeddedChannel outChannel, EmbeddedChannel inChannel,

codec-http/src/test/java/io/netty/handler/codec/http/websocketx/WebSocketHandshakeHandOverTest.java

@@ -50,7 +50,11 @@ public class WebSocketHandshakeHandOverTest {
 
     private final class CloseNoOpServerProtocolHandler extends WebSocketServerProtocolHandler {
         CloseNoOpServerProtocolHandler(String websocketPath) {
-            super(websocketPath, null, false);
+            super(WebSocketServerProtocolConfig.newBuilder()
+                .websocketPath(websocketPath)
+                .allowExtensions(false)
+                .sendCloseFrame(null)
+                .build());
         }
 
         @Override

codec-http/src/test/java/io/netty/handler/codec/http/websocketx/WebSocketServerProtocolHandlerTest.java

@@ -15,6 +15,7 @@
  */
 package io.netty.handler.codec.http.websocketx;
 
+import io.netty.buffer.ByteBuf;
 import io.netty.channel.ChannelHandler;
 import io.netty.channel.ChannelHandlerContext;
 import io.netty.channel.ChannelInboundHandler;
@@ -23,11 +24,14 @@ import io.netty.channel.embedded.EmbeddedChannel;
 import io.netty.handler.codec.http.DefaultFullHttpRequest;
 import io.netty.handler.codec.http.FullHttpRequest;
 import io.netty.handler.codec.http.FullHttpResponse;
+import io.netty.handler.codec.http.HttpClientCodec;
 import io.netty.handler.codec.http.HttpHeaderValues;
 import io.netty.handler.codec.http.HttpMethod;
+import io.netty.handler.codec.http.HttpObjectAggregator;
 import io.netty.handler.codec.http.HttpRequest;
 import io.netty.handler.codec.http.HttpRequestDecoder;
 import io.netty.handler.codec.http.HttpResponseEncoder;
+import io.netty.handler.codec.http.HttpServerCodec;
 import io.netty.util.CharsetUtil;
 import io.netty.util.ReferenceCountUtil;
 import org.junit.Before;
@@ -50,7 +54,7 @@ public class WebSocketServerProtocolHandlerTest {
     }
 
     @Test
-    public void testHttpUpgradeRequest() throws Exception {
+    public void testHttpUpgradeRequest() {
         EmbeddedChannel ch = createChannel(new MockOutboundHandler());
         ChannelHandlerContext handshakerCtx = ch.pipeline().context(WebSocketServerProtocolHandshakeHandler.class);
         writeUpgradeRequest(ch);
@@ -63,12 +67,12 @@ public class WebSocketServerProtocolHandlerTest {
     }
 
     @Test
-    public void testWebSocketServerProtocolHandshakeHandlerReplacedBeforeHandshake() throws Exception {
+    public void testWebSocketServerProtocolHandshakeHandlerReplacedBeforeHandshake() {
         EmbeddedChannel ch = createChannel(new MockOutboundHandler());
         ChannelHandlerContext handshakerCtx = ch.pipeline().context(WebSocketServerProtocolHandshakeHandler.class);
         ch.pipeline().addLast(new ChannelHandler() {
             @Override
-            public void userEventTriggered(ChannelHandlerContext ctx, Object evt) throws Exception {
+            public void userEventTriggered(ChannelHandlerContext ctx, Object evt) {
                 if (evt instanceof WebSocketServerProtocolHandler.HandshakeComplete) {
                     // We should have removed the handler already.
                     assertNull(ctx.pipeline().context(WebSocketServerProtocolHandshakeHandler.class));
@@ -85,7 +89,7 @@ public class WebSocketServerProtocolHandlerTest {
     }
 
     @Test
-    public void testSubsequentHttpRequestsAfterUpgradeShouldReturn403() throws Exception {
+    public void testSubsequentHttpRequestsAfterUpgradeShouldReturn403() {
         EmbeddedChannel ch = createChannel();
 
         writeUpgradeRequest(ch);
@@ -206,13 +210,160 @@ public class WebSocketServerProtocolHandlerTest {
         assertFalse(ch.finish());
     }
 
+    @Test
+    public void testExplicitCloseFrameSentWhenServerChannelClosed() throws Exception {
+        WebSocketCloseStatus closeStatus = WebSocketCloseStatus.ENDPOINT_UNAVAILABLE;
+        EmbeddedChannel client = createClient();
+        EmbeddedChannel server = createServer();
+
+        assertFalse(server.writeInbound(client.readOutbound()));
+        assertFalse(client.writeInbound(server.readOutbound()));
+
+        // When server channel closed with explicit close-frame
+        assertTrue(server.writeOutbound(new CloseWebSocketFrame(closeStatus)));
+        server.close();
+
+        // Then client receives provided close-frame
+        assertTrue(client.writeInbound(server.readOutbound()));
+        assertFalse(server.isOpen());
+
+        CloseWebSocketFrame closeMessage = client.readInbound();
+        assertEquals(closeMessage.statusCode(), closeStatus.code());
+        closeMessage.release();
+
+        client.close();
+        assertTrue(ReferenceCountUtil.release(client.readOutbound()));
+        assertFalse(client.finishAndReleaseAll());
+        assertFalse(server.finishAndReleaseAll());
+    }
+
+    @Test
+    public void testCloseFrameSentWhenServerChannelClosedSilently() throws Exception {
+        EmbeddedChannel client = createClient();
+        EmbeddedChannel server = createServer();
+
+        assertFalse(server.writeInbound(client.readOutbound()));
+        assertFalse(client.writeInbound(server.readOutbound()));
+
+        // When server channel closed without explicit close-frame
+        server.close();
+
+        // Then client receives NORMAL_CLOSURE close-frame
+        assertTrue(client.writeInbound(server.readOutbound()));
+        assertFalse(server.isOpen());
+
+        CloseWebSocketFrame closeMessage = client.readInbound();
+        assertEquals(closeMessage.statusCode(), WebSocketCloseStatus.NORMAL_CLOSURE.code());
+        closeMessage.release();
+
+        client.close();
+        assertTrue(ReferenceCountUtil.release(client.readOutbound()));
+        assertFalse(client.finishAndReleaseAll());
+        assertFalse(server.finishAndReleaseAll());
+    }
+
+    @Test
+    public void testExplicitCloseFrameSentWhenClientChannelClosed() throws Exception {
+        WebSocketCloseStatus closeStatus = WebSocketCloseStatus.INVALID_PAYLOAD_DATA;
+        EmbeddedChannel client = createClient();
+        EmbeddedChannel server = createServer();
+
+        assertFalse(server.writeInbound(client.readOutbound()));
+        assertFalse(client.writeInbound(server.readOutbound()));
+
+        // When client channel closed with explicit close-frame
+        assertTrue(client.writeOutbound(new CloseWebSocketFrame(closeStatus)));
+        client.close();
+
+        // Then client receives provided close-frame
+        assertFalse(server.writeInbound(client.readOutbound()));
+        assertFalse(client.isOpen());
+        assertFalse(server.isOpen());
+
+        CloseWebSocketFrame closeMessage = decode(server.<ByteBuf>readOutbound(), CloseWebSocketFrame.class);
+        assertEquals(closeMessage.statusCode(), closeStatus.code());
+        closeMessage.release();
+
+        assertFalse(client.finishAndReleaseAll());
+        assertFalse(server.finishAndReleaseAll());
+    }
+
+    @Test
+    public void testCloseFrameSentWhenClientChannelClosedSilently() throws Exception {
+        EmbeddedChannel client = createClient();
+        EmbeddedChannel server = createServer();
+
+        assertFalse(server.writeInbound(client.readOutbound()));
+        assertFalse(client.writeInbound(server.readOutbound()));
+
+        // When client channel closed without explicit close-frame
+        client.close();
+
+        // Then server receives NORMAL_CLOSURE close-frame
+        assertFalse(server.writeInbound(client.readOutbound()));
+        assertFalse(client.isOpen());
+        assertFalse(server.isOpen());
+
+        CloseWebSocketFrame closeMessage = decode(server.<ByteBuf>readOutbound(), CloseWebSocketFrame.class);
+        assertEquals(closeMessage, new CloseWebSocketFrame(WebSocketCloseStatus.NORMAL_CLOSURE));
+        closeMessage.release();
+
+        assertFalse(client.finishAndReleaseAll());
+        assertFalse(server.finishAndReleaseAll());
+    }
+
+    private EmbeddedChannel createClient(ChannelHandler... handlers) throws Exception {
+        WebSocketClientProtocolConfig clientConfig = WebSocketClientProtocolConfig.newBuilder()
+            .webSocketUri("http://test/test")
+            .dropPongFrames(false)
+            .handleCloseFrames(false)
+            .build();
+        EmbeddedChannel ch = new EmbeddedChannel(false, false,
+            new HttpClientCodec(),
+            new HttpObjectAggregator(8192),
+            new WebSocketClientProtocolHandler(clientConfig)
+        );
+        ch.pipeline().addLast(handlers);
+        ch.register();
+        return ch;
+    }
+
+    private EmbeddedChannel createServer(ChannelHandler... handlers) throws Exception {
+        WebSocketServerProtocolConfig serverConfig = WebSocketServerProtocolConfig.newBuilder()
+            .websocketPath("/test")
+            .dropPongFrames(false)
+            .build();
+        EmbeddedChannel ch = new EmbeddedChannel(false, false,
+            new HttpServerCodec(),
+            new HttpObjectAggregator(8192),
+            new WebSocketServerProtocolHandler(serverConfig)
+        );
+        ch.pipeline().addLast(handlers);
+        ch.register();
+        return ch;
+    }
+
+    @SuppressWarnings("SameParameterValue")
+    private <T> T decode(ByteBuf input, Class<T> clazz) {
+        EmbeddedChannel ch = new EmbeddedChannel(new WebSocket13FrameDecoder(true, false, 65536, true));
+        assertTrue(ch.writeInbound(input));
+        Object decoded = ch.readInbound();
+        assertNotNull(decoded);
+        assertFalse(ch.finish());
+        return clazz.cast(decoded);
+    }
+
     private EmbeddedChannel createChannel() {
         return createChannel(null);
     }
 
     private EmbeddedChannel createChannel(ChannelHandler handler) {
+        WebSocketServerProtocolConfig serverConfig = WebSocketServerProtocolConfig.newBuilder()
+            .websocketPath("/test")
+            .sendCloseFrame(null)
+            .build();
         return new EmbeddedChannel(
-                new WebSocketServerProtocolHandler("/test"),
+                new WebSocketServerProtocolHandler(serverConfig),
                 new HttpRequestDecoder(),
                 new HttpResponseEncoder(),
                 new MockOutboundHandler(),
@@ -230,13 +381,13 @@ public class WebSocketServerProtocolHandlerTest {
     private class MockOutboundHandler implements ChannelHandler {
 
         @Override
-        public void write(ChannelHandlerContext ctx, Object msg, ChannelPromise promise) throws Exception {
+        public void write(ChannelHandlerContext ctx, Object msg, ChannelPromise promise) {
             responses.add((FullHttpResponse) msg);
             promise.setSuccess();
         }
 
         @Override
-        public void flush(ChannelHandlerContext ctx) throws Exception {
+        public void flush(ChannelHandlerContext ctx) {
         }
     }
 
@@ -244,7 +395,7 @@ public class WebSocketServerProtocolHandlerTest {
         private String content;
 
         @Override
-        public void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception {
+        public void channelRead(ChannelHandlerContext ctx, Object msg) {
             assertNull(content);
             content = "processed: " + ((TextWebSocketFrame) msg).text();
             ReferenceCountUtil.release(msg);