ch.rasc.wampspring.session.WebSocketRegistryListener.java Source code

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Here is the source code for ch.rasc.wampspring.session.WebSocketRegistryListener.java

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/*
 * Copyright 2015 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 ch.rasc.wampspring.session;

import java.io.IOException;
import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.springframework.context.ApplicationEvent;
import org.springframework.context.ApplicationListener;
import org.springframework.session.events.SessionDestroyedEvent;
import org.springframework.session.web.socket.events.SessionConnectEvent;
import org.springframework.web.socket.CloseStatus;
import org.springframework.web.socket.WebSocketSession;

/**
 * <p>
 * Keeps track of mapping the Spring Session ID to the {@link WebSocketSession} and
 * ensuring when a {@link SessionDestroyedEvent} is fired that the
 * {@link WebSocketSession} is closed.
 * </p>
 *
 * @author Rob Winch
 * @author Ralph Schaer
 */
public final class WebSocketRegistryListener implements ApplicationListener<ApplicationEvent> {

    private static final Log logger = LogFactory.getLog(WebSocketRegistryListener.class);

    static final CloseStatus SESSION_EXPIRED_STATUS = new CloseStatus(CloseStatus.POLICY_VIOLATION.getCode(),
            "This connection was established under an authenticated HTTP Session that has expired");

    private final ConcurrentHashMap<String, Map<String, WebSocketSession>> httpSessionIdToWsSessions = new ConcurrentHashMap<>();

    @Override
    public void onApplicationEvent(ApplicationEvent event) {
        if (event instanceof SessionDestroyedEvent) {
            SessionDestroyedEvent e = (SessionDestroyedEvent) event;
            closeWsSessions(e.getSessionId());
        } else if (event instanceof SessionConnectEvent) {
            SessionConnectEvent e = (SessionConnectEvent) event;
            afterWsConnectionEstablished(e.getWebSocketSession());
        } else if (event instanceof SessionDisconnectEvent) {
            SessionDisconnectEvent e = (SessionDisconnectEvent) event;
            afterWsConnectionClosed(e.getWebSocketSession());
        }
    }

    private void afterWsConnectionEstablished(WebSocketSession wsSession) {
        registerWsSession(wsSession);
    }

    private void afterWsConnectionClosed(WebSocketSession wsSession) {
        String httpSessionId = (String) wsSession.getAttributes().get(SessionSupport.SPRING_SESSION_ID_ATTR_NAME);
        if (httpSessionId == null) {
            return;
        }

        Map<String, WebSocketSession> sessions = this.httpSessionIdToWsSessions.get(httpSessionId);
        if (sessions != null) {
            String wsSessionId = wsSession.getId();
            boolean result = sessions.remove(wsSessionId) != null;
            if (logger.isDebugEnabled()) {
                logger.debug("Removal of " + wsSessionId + " was " + result);
            }
            if (sessions.isEmpty()) {
                this.httpSessionIdToWsSessions.remove(httpSessionId);
                if (logger.isDebugEnabled()) {
                    logger.debug("Removed the corresponding HTTP Session for " + wsSessionId
                            + " since it contained no WebSocket mappings");
                }
            }
        }
    }

    private void registerWsSession(WebSocketSession wsSession) {
        String httpSessionId = (String) wsSession.getAttributes().get(SessionSupport.SPRING_SESSION_ID_ATTR_NAME);
        if (httpSessionId == null) {
            return;
        }

        Map<String, WebSocketSession> sessions = this.httpSessionIdToWsSessions.get(httpSessionId);
        if (sessions == null) {
            sessions = new ConcurrentHashMap<>();
            this.httpSessionIdToWsSessions.putIfAbsent(httpSessionId, sessions);
            sessions = this.httpSessionIdToWsSessions.get(httpSessionId);
        }
        sessions.put(wsSession.getId(), wsSession);
    }

    private void closeWsSessions(String httpSessionId) {
        Map<String, WebSocketSession> sessionsToClose = this.httpSessionIdToWsSessions.remove(httpSessionId);
        if (sessionsToClose == null) {
            return;
        }
        if (logger.isDebugEnabled()) {
            logger.debug("Closing WebSocket connections associated to expired HTTP Session " + httpSessionId);
        }
        for (WebSocketSession toClose : sessionsToClose.values()) {
            try {
                toClose.close(SESSION_EXPIRED_STATUS);
            } catch (IOException e) {
                logger.debug(
                        "Failed to close WebSocketSession (this is nothing to worry about but for debugging only)",
                        e);
            }
        }
    }
}