org.apache.tomcat.websocket.server.WsRemoteEndpointImplServer Maven / Gradle / Ivy
/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF 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 org.apache.tomcat.websocket.server;
import java.io.EOFException;
import java.io.IOException;
import java.net.SocketTimeoutException;
import java.nio.ByteBuffer;
import java.util.concurrent.Executor;
import javax.websocket.SendHandler;
import javax.websocket.SendResult;
import org.apache.juli.logging.Log;
import org.apache.juli.logging.LogFactory;
import org.apache.tomcat.util.net.AbstractEndpoint;
import org.apache.tomcat.util.net.SocketWrapperBase;
import org.apache.tomcat.util.res.StringManager;
import org.apache.tomcat.websocket.Transformation;
import org.apache.tomcat.websocket.WsRemoteEndpointImplBase;
/**
* This is the server side {@link javax.websocket.RemoteEndpoint} implementation
* - i.e. what the server uses to send data to the client.
*/
public class WsRemoteEndpointImplServer extends WsRemoteEndpointImplBase {
private static final StringManager sm =
StringManager.getManager(WsRemoteEndpointImplServer.class);
private final Log log = LogFactory.getLog(WsRemoteEndpointImplServer.class); // must not be static
private final SocketWrapperBase socketWrapper;
private final WsWriteTimeout wsWriteTimeout;
private volatile SendHandler handler = null;
private volatile ByteBuffer[] buffers = null;
private volatile long timeoutExpiry = -1;
private volatile boolean close;
public WsRemoteEndpointImplServer(SocketWrapperBase socketWrapper,
WsServerContainer serverContainer) {
this.socketWrapper = socketWrapper;
this.wsWriteTimeout = serverContainer.getTimeout();
}
@Override
protected final boolean isMasked() {
return false;
}
@Override
protected void doWrite(SendHandler handler, long blockingWriteTimeoutExpiry,
ByteBuffer... buffers) {
if (blockingWriteTimeoutExpiry == -1) {
this.handler = handler;
this.buffers = buffers;
// This is definitely the same thread that triggered the write so a
// dispatch will be required.
onWritePossible(true);
} else {
// Blocking
try {
for (ByteBuffer buffer : buffers) {
long timeout = blockingWriteTimeoutExpiry - System.currentTimeMillis();
if (timeout <= 0) {
SendResult sr = new SendResult(new SocketTimeoutException());
handler.onResult(sr);
return;
}
socketWrapper.setWriteTimeout(timeout);
socketWrapper.write(true, buffer);
}
long timeout = blockingWriteTimeoutExpiry - System.currentTimeMillis();
if (timeout <= 0) {
SendResult sr = new SendResult(new SocketTimeoutException());
handler.onResult(sr);
return;
}
socketWrapper.setWriteTimeout(timeout);
socketWrapper.flush(true);
handler.onResult(SENDRESULT_OK);
} catch (IOException e) {
SendResult sr = new SendResult(e);
handler.onResult(sr);
}
}
}
public void onWritePossible(boolean useDispatch) {
ByteBuffer[] buffers = this.buffers;
if (buffers == null) {
// Servlet 3.1 will call the write listener once even if nothing
// was written
return;
}
boolean complete = false;
try {
socketWrapper.flush(false);
// If this is false there will be a call back when it is true
while (socketWrapper.isReadyForWrite()) {
complete = true;
for (ByteBuffer buffer : buffers) {
if (buffer.hasRemaining()) {
complete = false;
socketWrapper.write(false, buffer);
break;
}
}
if (complete) {
socketWrapper.flush(false);
complete = socketWrapper.isReadyForWrite();
if (complete) {
wsWriteTimeout.unregister(this);
clearHandler(null, useDispatch);
if (close) {
close();
}
}
break;
}
}
} catch (IOException | IllegalStateException e) {
wsWriteTimeout.unregister(this);
clearHandler(e, useDispatch);
close();
}
if (!complete) {
// Async write is in progress
long timeout = getSendTimeout();
if (timeout > 0) {
// Register with timeout thread
timeoutExpiry = timeout + System.currentTimeMillis();
wsWriteTimeout.register(this);
}
}
}
@Override
protected void doClose() {
if (handler != null) {
// close() can be triggered by a wide range of scenarios. It is far
// simpler just to always use a dispatch than it is to try and track
// whether or not this method was called by the same thread that
// triggered the write
clearHandler(new EOFException(), true);
}
try {
socketWrapper.close();
} catch (IOException e) {
if (log.isInfoEnabled()) {
log.info(sm.getString("wsRemoteEndpointServer.closeFailed"), e);
}
}
wsWriteTimeout.unregister(this);
}
protected long getTimeoutExpiry() {
return timeoutExpiry;
}
/*
* Currently this is only called from the background thread so we could just
* call clearHandler() with useDispatch == false but the method parameter
* was added in case other callers started to use this method to make sure
* that those callers think through what the correct value of useDispatch is
* for them.
*/
protected void onTimeout(boolean useDispatch) {
if (handler != null) {
clearHandler(new SocketTimeoutException(), useDispatch);
}
close();
}
@Override
protected void setTransformation(Transformation transformation) {
// Overridden purely so it is visible to other classes in this package
super.setTransformation(transformation);
}
/**
*
* @param t The throwable associated with any error that
* occurred
* @param useDispatch Should {@link SendHandler#onResult(SendResult)} be
* called from a new thread, keeping in mind the
* requirements of
* {@link javax.websocket.RemoteEndpoint.Async}
*/
private void clearHandler(Throwable t, boolean useDispatch) {
// Setting the result marks this (partial) message as
// complete which means the next one may be sent which
// could update the value of the handler. Therefore, keep a
// local copy before signalling the end of the (partial)
// message.
SendHandler sh = handler;
handler = null;
buffers = null;
if (sh != null) {
if (useDispatch) {
OnResultRunnable r = new OnResultRunnable(sh, t);
AbstractEndpoint endpoint = socketWrapper.getEndpoint();
Executor containerExecutor = endpoint.getExecutor();
if (endpoint.isRunning() && containerExecutor != null) {
containerExecutor.execute(r);
} else {
// Can't use the executor so call the runnable directly.
// This may not be strictly specification compliant in all
// cases but during shutdown only close messages are going
// to be sent so there should not be the issue of nested
// calls leading to stack overflow as described in bug
// 55715. The issues with nested calls was the reason for
// the separate thread requirement in the specification.
r.run();
}
} else {
if (t == null) {
sh.onResult(new SendResult());
} else {
sh.onResult(new SendResult(t));
}
}
}
}
private static class OnResultRunnable implements Runnable {
private final SendHandler sh;
private final Throwable t;
private OnResultRunnable(SendHandler sh, Throwable t) {
this.sh = sh;
this.t = t;
}
@Override
public void run() {
if (t == null) {
sh.onResult(new SendResult());
} else {
sh.onResult(new SendResult(t));
}
}
}
}