/*
* Copyright 2002-2014 the original author or authors.
*
* Licensed 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.springframework.web.socket.messaging;
import java.io.IOException;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import java.util.Map;
import java.util.TreeMap;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.atomic.AtomicInteger;
import java.util.concurrent.locks.ReentrantLock;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.springframework.context.SmartLifecycle;
import org.springframework.messaging.Message;
import org.springframework.messaging.MessageChannel;
import org.springframework.messaging.MessageHandler;
import org.springframework.messaging.MessagingException;
import org.springframework.messaging.SubscribableChannel;
import org.springframework.util.Assert;
import org.springframework.util.CollectionUtils;
import org.springframework.util.StringUtils;
import org.springframework.web.socket.CloseStatus;
import org.springframework.web.socket.SubProtocolCapable;
import org.springframework.web.socket.WebSocketHandler;
import org.springframework.web.socket.WebSocketMessage;
import org.springframework.web.socket.WebSocketSession;
import org.springframework.web.socket.handler.ConcurrentWebSocketSessionDecorator;
import org.springframework.web.socket.handler.SessionLimitExceededException;
import org.springframework.web.socket.sockjs.transport.session.PollingSockJsSession;
import org.springframework.web.socket.sockjs.transport.session.StreamingSockJsSession;
/**
* An implementation of {@link WebSocketHandler} that delegates incoming WebSocket
* messages to a {@link SubProtocolHandler} along with a {@link MessageChannel} to
* which the sub-protocol handler can send messages from WebSocket clients to
* the application.
* <p>
* Also an implementation of {@link MessageHandler} that finds the WebSocket
* session associated with the {@link Message} and passes it, along with the message,
* to the sub-protocol handler to send messages from the application back to the
* client.
*
* @author Rossen Stoyanchev
* @author Andy Wilkinson
* @author Artem Bilan
* @since 4.0
*/
public class SubProtocolWebSocketHandler implements WebSocketHandler,
SubProtocolCapable, MessageHandler, SmartLifecycle {
/**
* Sessions connected to this handler use a sub-protocol. Hence we expect to
* receive some client messages. If we don't receive any within a minute, the
* connection isn't doing well (proxy issue, slow network?) and can be closed.
* @see #checkSessions()
*/
private static final int TIME_TO_FIRST_MESSAGE = 60 * 1000;
private final Log logger = LogFactory.getLog(SubProtocolWebSocketHandler.class);
private final MessageChannel clientInboundChannel;
private final SubscribableChannel clientOutboundChannel;
private final Map<String, SubProtocolHandler> protocolHandlerLookup =
new TreeMap<String, SubProtocolHandler>(String.CASE_INSENSITIVE_ORDER);
private final List<SubProtocolHandler> protocolHandlers = new ArrayList<SubProtocolHandler>();
private SubProtocolHandler defaultProtocolHandler;
private final Map<String, WebSocketSessionHolder> sessions = new ConcurrentHashMap<String, WebSocketSessionHolder>();
private int sendTimeLimit = 10 * 1000;
private int sendBufferSizeLimit = 512 * 1024;
private volatile long lastSessionCheckTime = System.currentTimeMillis();
private final ReentrantLock sessionCheckLock = new ReentrantLock();
private final Stats stats = new Stats();
private final Object lifecycleMonitor = new Object();
private volatile boolean running = false;
public SubProtocolWebSocketHandler(MessageChannel clientInboundChannel, SubscribableChannel clientOutboundChannel) {
Assert.notNull(clientInboundChannel, "ClientInboundChannel must not be null");
Assert.notNull(clientOutboundChannel, "ClientOutboundChannel must not be null");
this.clientInboundChannel = clientInboundChannel;
this.clientOutboundChannel = clientOutboundChannel;
}
/**
* Configure one or more handlers to use depending on the sub-protocol requested by
* the client in the WebSocket handshake request.
* @param protocolHandlers the sub-protocol handlers to use
*/
public void setProtocolHandlers(List<SubProtocolHandler> protocolHandlers) {
this.protocolHandlerLookup.clear();
this.protocolHandlers.clear();
for (SubProtocolHandler handler: protocolHandlers) {
addProtocolHandler(handler);
}
}
public List<SubProtocolHandler> getProtocolHandlers() {
return new ArrayList<SubProtocolHandler>(this.protocolHandlerLookup.values());
}
/**
* Register a sub-protocol handler.
*/
public void addProtocolHandler(SubProtocolHandler handler) {
List<String> protocols = handler.getSupportedProtocols();
if (CollectionUtils.isEmpty(protocols)) {
logger.error("No sub-protocols for " + handler + ".");
return;
}
for (String protocol: protocols) {
SubProtocolHandler replaced = this.protocolHandlerLookup.put(protocol, handler);
if ((replaced != null) && (replaced != handler) ) {
throw new IllegalStateException("Can't map " + handler +
" to protocol '" + protocol + "'. Already mapped to " + replaced + ".");
}
}
this.protocolHandlers.add(handler);
}
/**
* Return the sub-protocols keyed by protocol name.
*/
public Map<String, SubProtocolHandler> getProtocolHandlerMap() {
return this.protocolHandlerLookup;
}
/**
* Set the {@link SubProtocolHandler} to use when the client did not request a
* sub-protocol.
* @param defaultProtocolHandler the default handler
*/
public void setDefaultProtocolHandler(SubProtocolHandler defaultProtocolHandler) {
this.defaultProtocolHandler = defaultProtocolHandler;
if (this.protocolHandlerLookup.isEmpty()) {
setProtocolHandlers(Arrays.asList(defaultProtocolHandler));
}
}
/**
* @return the default sub-protocol handler to use
*/
public SubProtocolHandler getDefaultProtocolHandler() {
return this.defaultProtocolHandler;
}
/**
* Return all supported protocols.
*/
public List<String> getSubProtocols() {
return new ArrayList<String>(this.protocolHandlerLookup.keySet());
}
public void setSendTimeLimit(int sendTimeLimit) {
this.sendTimeLimit = sendTimeLimit;
}
public int getSendTimeLimit() {
return this.sendTimeLimit;
}
public void setSendBufferSizeLimit(int sendBufferSizeLimit) {
this.sendBufferSizeLimit = sendBufferSizeLimit;
}
public int getSendBufferSizeLimit() {
return sendBufferSizeLimit;
}
@Override
public boolean isAutoStartup() {
return true;
}
@Override
public int getPhase() {
return Integer.MAX_VALUE;
}
@Override
public final boolean isRunning() {
synchronized (this.lifecycleMonitor) {
return this.running;
}
}
/**
* Return a String describing internal state and counters.
*/
public String getStatsInfo() {
return this.stats.toString();
}
@Override
public final void start() {
Assert.isTrue(this.defaultProtocolHandler != null || !this.protocolHandlers.isEmpty(), "No handlers");
synchronized (this.lifecycleMonitor) {
this.clientOutboundChannel.subscribe(this);
this.running = true;
}
}
@Override
public final void stop() {
synchronized (this.lifecycleMonitor) {
this.running = false;
this.clientOutboundChannel.unsubscribe(this);
for (WebSocketSessionHolder holder : this.sessions.values()) {
try {
holder.getSession().close(CloseStatus.GOING_AWAY);
}
catch (Throwable t) {
logger.error("Failed to close '" + holder.getSession() + "': " + t.getMessage());
}
}
}
}
@Override
public final void stop(Runnable callback) {
synchronized (this.lifecycleMonitor) {
stop();
callback.run();
}
}
@Override
public void afterConnectionEstablished(WebSocketSession session) throws Exception {
this.stats.incrementSessionCount(session);
session = new ConcurrentWebSocketSessionDecorator(session, getSendTimeLimit(), getSendBufferSizeLimit());
this.sessions.put(session.getId(), new WebSocketSessionHolder(session));
findProtocolHandler(session).afterSessionStarted(session, this.clientInboundChannel);
}
protected final SubProtocolHandler findProtocolHandler(WebSocketSession session) {
String protocol = null;
try {
protocol = session.getAcceptedProtocol();
}
catch (Exception ex) {
// Shouldn't happen
logger.error("Failed to obtain session.getAcceptedProtocol(). Will use the " +
"default protocol handler (if configured).", ex);
}
SubProtocolHandler handler;
if (!StringUtils.isEmpty(protocol)) {
handler = this.protocolHandlerLookup.get(protocol);
Assert.state(handler != null, "No handler for '" + protocol + "' among " + this.protocolHandlerLookup);
}
else {
if (this.defaultProtocolHandler != null) {
handler = this.defaultProtocolHandler;
}
else if (this.protocolHandlers.size() == 1) {
handler = this.protocolHandlers.get(0);
}
else {
throw new IllegalStateException("Multiple protocol handlers configured and " +
"no protocol was negotiated. Consider configuring a default SubProtocolHandler.");
}
}
return handler;
}
/**
* Handle an inbound message from a WebSocket client.
*/
@Override
public void handleMessage(WebSocketSession session, WebSocketMessage<?> message) throws Exception {
SubProtocolHandler protocolHandler = findProtocolHandler(session);
protocolHandler.handleMessageFromClient(session, message, this.clientInboundChannel);
WebSocketSessionHolder holder = this.sessions.get(session.getId());
if (holder != null) {
holder.setHasHandledMessages();
}
checkSessions();
}
/**
* Handle an outbound Spring Message to a WebSocket client.
*/
@Override
public void handleMessage(Message<?> message) throws MessagingException {
String sessionId = resolveSessionId(message);
if (sessionId == null) {
logger.error("Couldn't find sessionId in " + message);
return;
}
WebSocketSessionHolder holder = this.sessions.get(sessionId);
if (holder == null) {
if (logger.isDebugEnabled()) {
// The broker may not have removed the session yet
logger.debug("No session for " + message);
}
return;
}
WebSocketSession session = holder.getSession();
try {
findProtocolHandler(session).handleMessageToClient(session, message);
}
catch (SessionLimitExceededException ex) {
try {
if (logger.isDebugEnabled()) {
logger.debug("Terminating '" + session + "'", ex);
}
this.stats.incrementLimitExceededCount();
clearSession(session, ex.getStatus()); // clear first, session may be unresponsive
session.close(ex.getStatus());
}
catch (Exception secondException) {
logger.debug("Failure while closing session " + sessionId + ".", secondException);
}
}
catch (Exception e) {
// Could be part of normal workflow (e.g. browser tab closed)
logger.debug("Failed to send message to client in " + session + ": " + message, e);
}
}
private String resolveSessionId(Message<?> message) {
for (SubProtocolHandler handler : this.protocolHandlerLookup.values()) {
String sessionId = handler.resolveSessionId(message);
if (sessionId != null) {
return sessionId;
}
}
if (this.defaultProtocolHandler != null) {
String sessionId = this.defaultProtocolHandler.resolveSessionId(message);
if (sessionId != null) {
return sessionId;
}
}
return null;
}
/**
* When a session is connected through a higher-level protocol it has a chance
* to use heartbeat management to shut down sessions that are too slow to send
* or receive messages. However, after a WebSocketSession is established and
* before the higher level protocol is fully connected there is a possibility
* for sessions to hang. This method checks and closes any sessions that have
* been connected for more than 60 seconds without having received a single
* message.
*/
private void checkSessions() throws IOException {
long currentTime = System.currentTimeMillis();
if (!isRunning() || (currentTime - this.lastSessionCheckTime < TIME_TO_FIRST_MESSAGE)) {
return;
}
if (this.sessionCheckLock.tryLock()) {
try {
for (WebSocketSessionHolder holder : this.sessions.values()) {
if (holder.hasHandledMessages()) {
continue;
}
long timeSinceCreated = currentTime - holder.getCreateTime();
if (timeSinceCreated < TIME_TO_FIRST_MESSAGE) {
continue;
}
WebSocketSession session = holder.getSession();
if (logger.isErrorEnabled()) {
logger.error("No messages received after " + timeSinceCreated + " ms. " +
"Closing " + holder.getSession() + ".");
}
try {
this.stats.incrementNoMessagesReceivedCount();
session.close(CloseStatus.SESSION_NOT_RELIABLE);
}
catch (Throwable t) {
logger.error("Failure while closing " + session, t);
}
}
}
finally {
this.sessionCheckLock.unlock();
}
}
}
@Override
public void handleTransportError(WebSocketSession session, Throwable exception) throws Exception {
this.stats.incrementTransportError();
}
@Override
public void afterConnectionClosed(WebSocketSession session, CloseStatus closeStatus) throws Exception {
clearSession(session, closeStatus);
}
private void clearSession(WebSocketSession session, CloseStatus closeStatus) throws Exception {
if (logger.isDebugEnabled()) {
logger.debug("Clearing session " + session.getId());
}
if (this.sessions.remove(session.getId()) != null) {
this.stats.decrementSessionCount(session);
}
findProtocolHandler(session).afterSessionEnded(session, closeStatus, this.clientInboundChannel);
}
@Override
public boolean supportsPartialMessages() {
return false;
}
@Override
public String toString() {
return "SubProtocolWebSocketHandler" + getProtocolHandlers();
}
private static class WebSocketSessionHolder {
private final WebSocketSession session;
private final long createTime = System.currentTimeMillis();
private volatile boolean handledMessages;
private WebSocketSessionHolder(WebSocketSession session) {
this.session = session;
}
public WebSocketSession getSession() {
return this.session;
}
public long getCreateTime() {
return this.createTime;
}
public void setHasHandledMessages() {
this.handledMessages = true;
}
public boolean hasHandledMessages() {
return this.handledMessages;
}
@Override
public String toString() {
return "WebSocketSessionHolder[=session=" + this.session + ", createTime=" +
this.createTime + ", hasHandledMessages=" + this.handledMessages + "]";
}
}
private class Stats {
private final AtomicInteger total = new AtomicInteger();
private final AtomicInteger webSocket = new AtomicInteger();
private final AtomicInteger httpStreaming = new AtomicInteger();
private final AtomicInteger httpPolling = new AtomicInteger();
private final AtomicInteger limitExceeded = new AtomicInteger();
private final AtomicInteger noMessagesReceived = new AtomicInteger();
private final AtomicInteger transportError = new AtomicInteger();
public void incrementSessionCount(WebSocketSession session) {
getCountFor(session).incrementAndGet();
this.total.incrementAndGet();
}
public void decrementSessionCount(WebSocketSession session) {
getCountFor(session).decrementAndGet();
}
public void incrementLimitExceededCount() {
this.limitExceeded.incrementAndGet();
}
public void incrementNoMessagesReceivedCount() {
this.noMessagesReceived.incrementAndGet();
}
public void incrementTransportError() {
this.transportError.incrementAndGet();
}
private AtomicInteger getCountFor(WebSocketSession session) {
if (session instanceof PollingSockJsSession) {
return this.httpPolling;
}
else if (session instanceof StreamingSockJsSession) {
return this.httpStreaming;
}
else {
return this.webSocket;
}
}
public String toString() {
return SubProtocolWebSocketHandler.this.sessions.size() +
" current WS(" + this.webSocket.get() +
")-HttpStream(" + this.httpStreaming.get() +
")-HttpPoll(" + this.httpPolling.get() + "), " +
this.total.get() + " total, " +
(this.limitExceeded.get() + this.noMessagesReceived.get()) + " closed abnormally (" +
this.noMessagesReceived.get() + " connect failure, " +
this.limitExceeded.get() + " send limit, " +
this.transportError.get() + " transport error)";
}
}
}