httpd代理连接超时后的TomEE websocket

Question

在开发过程中，我有一个javascript websocket直接连接到TomEE，并且该websocket保持连接，没有任何问题。

在使用httpd代理的TomEE进行生产时，连接会在大约30秒后超时。

以下是虚拟主机配置的相关部分

ProxyPass / ajp://127.0.0.1:8009/ secret=xxxxxxxxxxxx
RewriteEngine on
RewriteCond %{HTTP:Upgrade} websocket [NC]
RewriteCond %{HTTP:Connection} upgrade [NC]
RewriteRule ^/?(.*) "ws://127.0.0.1:8080/$1" [P,L]

我尝试过使用重新连接的websocket npm库，但它似乎一直在生成websocket，直到chrome耗尽内存。原始的websocket保持状态101，而不是更改为已完成。

我确实读到防火墙会导致它断开连接，但我搜索了firewalld和websocket，找不到任何

Answer 1

看起来答案是实现"乒乓球；。这样可以防止防火墙或代理终止连接。

如果你ping一个websocket(客户端或服务器(，那么规范说它必须响应(pong(。但是Javascript websocket依赖于浏览器的实现，所以最好在服务器上对所有客户端实现30秒的ping。例如

import java.io.IOException;
import java.nio.ByteBuffer;
import java.util.Collections;
import java.util.HashSet;
import java.util.Set;
import javax.websocket.OnClose;
import javax.websocket.OnError;
import javax.websocket.OnMessage;
import javax.websocket.OnOpen;
import javax.websocket.PongMessage;
import javax.websocket.Session;
import javax.websocket.server.ServerEndpoint;
@ServerEndpoint(value = "/websockets/admin/autoreply")
public class MyWebSocket {
private static final Set<Session> sessions = Collections.synchronizedSet(new HashSet<Session>());
private static final Set<String> alive = Collections.synchronizedSet(new HashSet<String>());
@OnOpen
public void onOpen(Session session) throws IOException {
sessions.add(session);
alive.add(session.getId());
}
@OnMessage
public void onMessage(Session session, String string) throws IOException {
//       broadcast(string);
}
@OnMessage
public void onPong(Session session, PongMessage pongMessage) throws IOException {
//      System.out.println("pong");
alive.add(session.getId());
}
@OnClose
public void onClose(Session session) throws IOException {
sessions.remove(session);
}
@OnError
public void onError(Session session, Throwable throwable) {
// Do error handling here
}
public void broadcast(String string) {
synchronized (sessions) {
for (Session session : sessions) {
broadcast(session, string);
}
}
}
private void broadcast(Session session, String string) {
try {
session.getBasicRemote().sendText(string);
} catch (IOException ex) {
ex.printStackTrace();
}
}
public void ping() {
synchronized (sessions) {
for (Session session : sessions) {
ping(session);
}
}
}
private void ping(Session session) {
try {
synchronized (alive) {
if (alive.contains(session.getId())) {
String data = "Ping";
ByteBuffer payload = ByteBuffer.wrap(data.getBytes());
session.getBasicRemote().sendPing(payload);
alive.remove(session.getId());
} else {
session.close();
}
}
} catch (IOException ex) {
ex.printStackTrace();
}
}
}

计时器服务看起来像这个

import javax.annotation.PostConstruct;
import javax.annotation.Resource;
import javax.ejb.Lock;
import javax.ejb.LockType;
import javax.ejb.ScheduleExpression;
import javax.ejb.Singleton;
import javax.ejb.Startup;
import javax.ejb.Timeout;
import javax.ejb.Timer;
import javax.ejb.TimerConfig;
import javax.ejb.TimerService;
import org.apache.tomcat.websocket.server.DefaultServerEndpointConfigurator;
import tld.domain.api.websockets.MyWebSocket;
@Singleton
@Lock(LockType.READ)
@Startup
public class HeartbeatTimer {
@Resource
private TimerService timerService;
@PostConstruct
private void construct() {
final TimerConfig heartbeat = new TimerConfig("heartbeat", false);
timerService.createCalendarTimer(new ScheduleExpression().second("*/30").minute("*").hour("*"), heartbeat);
}
@Timeout
public void timeout(Timer timer) {
if ("heartbeat".equals(timer.getInfo())) {
//          System.out.println("Pinging...");
try {
DefaultServerEndpointConfigurator dsec = new DefaultServerEndpointConfigurator();
MyWebSocket ws = dsec.getEndpointInstance(MyWebSocket.class);
ws.ping();
} catch (InstantiationException e) {
e.printStackTrace();
}           
}
}
}