第一部分 Jabber Server工作原理和流程
1)Server的啓動
通過下面圖片來做一個簡單的瞭解
1. 按Launcher(GUI)是Jive Messenger Server啓動和停止的可視化界面,
按下Start鍵Server開始啓動
注:[org.jivesoftware.messenger.launcher.Launcher]調用ServerStarter.start()
2. [org.jivesoftware.messenger.starter.ServerStarter]加載lib庫文件,同時啓動一個
[org.jivesoftware.messenger.XMPPServer]實體
|
Class containerClass = loader.loadClass("org.jivesoftware.messenger.XMPPServer");
containerClass.newInstance();
|
3. XMPPServer加載模塊(Modules),組件(Component),插件(Plugin)
|
public void start() {
try {
initialize();
// If the server has already been setup then we can start all the server's modules
if (!setupMode) {
verifyDataSource();
// First load all the modules so that modules may access other modules while
// being initialized
loadModules();
// Initize all the modules
initModules();
// Start all the modules
startModules();
}
// Load plugins. First, initialize component manager.
InternalComponentManager.getInstance().start();
File pluginDir = new File(messengerHome, "plugins");
pluginManager = new PluginManager(pluginDir);
pluginManager.start();
…….
}
catch (Exception e) {
…..
shutdownServer();
}
}
|
下面我們來看一下服務器加載了那些Module(Component,Plugin也是非常重要的我將在以後的文章中做討論)
|
private void loadModules() {
// Load boot modules
loadModule(RoutingTableImpl.class.getName());
loadModule(AuditManagerImpl.class.getName());
loadModule(RosterManager.class.getName());
loadModule(PrivateStorage.class.getName());
// Load core modules
loadModule(PresenceManagerImpl.class.getName());
loadModule(SessionManager.class.getName());
loadModule(PacketRouter.class.getName());
loadModule(IQRouter.class.getName());
loadModule(MessageRouter.class.getName());
loadModule(PresenceRouter.class.getName());
loadModule(PacketTransporterImpl.class.getName());
loadModule(PacketDelivererImpl.class.getName());
loadModule(TransportHandler.class.getName());
loadModule(OfflineMessageStrategy.class.getName());
loadModule(OfflineMessageStore.class.getName());
// Load standard modules
loadModule(IQAuthHandler.class.getName());
loadModule(IQPrivateHandler.class.getName());
loadModule(IQRegisterHandler.class.getName());
loadModule(IQRosterHandler.class.getName());
loadModule(IQTimeHandler.class.getName());
loadModule(IQvCardHandler.class.getName());
loadModule(IQVersionHandler.class.getName());
loadModule(IQLastActivityHandler.class.getName());
loadModule(PresenceSubscribeHandler.class.getName());
loadModule(PresenceUpdateHandler.class.getName());
loadModule(IQDiscoInfoHandler.class.getName());
loadModule(IQDiscoItemsHandler.class.getName());
loadModule(IQOfflineMessagesHandler.class.getName());
loadModule(MultiUserChatServerImpl.class.getName());
loadModule(MulticastDNSService.class.getName());
// Load this module always last since we don't want to start listening for clients
// before the rest of the modules have been started
loadModule(ConnectionManagerImpl.class.getName());
}
|
Server啓動的時候加載的模塊非常多,其中最後一個加載的ConnectionManagerImpl它是ConnectionManager接口的實現,用來負責管理用戶(jabberClient)連接
另外所有模塊都是繼承(extends)了BasicModule或者實現(implements)了Module
4. ConnectionManageImpl啓動
|
public void start() {
super.start();
isStarted = true;
serverName = server.getServerInfo().getName();
createSocket();
SocketSendingTracker.getInstance().start();
}
|
Start方法創建Socket(監聽客戶端的連接),並啓動一個SocketSendingTracker線程,用來檢查Socket是否正常連接
5.JabberServer啓動完成
2)客戶端連接,待續
2）Client和Server交互流程
1． 客戶端啓動一個XMPPConnection和Server建立Socket的連接
2． 用戶通過PacketWriter發IQ給Server，服務器ClientSocketReader接受到這個IQ，對用戶登陸進行認證
3． 當ClientA發Packet給ClientB的ClientSocketReader會調用PacketRouter把Packet轉發給ClientB（現在先不太Server2Server的情況）
Jive Messenger Server如何創建Session（代碼分析）
ConnectionManagerImpl初始化（
|
//ConnectionManagerImpl.java
public void initialize(XMPPServer server) {
super.initialize(server);
this.server = server;
router = server.getPacketRouter();
deliverer = server.getPacketDeliverer();
sessionManager = server.getSessionManager();
}
|
ConnectionManagerImpl啓動
|
//ConnectionManagerImpl.java
public void start() {
super.start();
isStarted = true;
serverName = server.getServerInfo().getName();
createSocket();
SocketSendingTracker.getInstance().start();
}
|
ConnectionManagerImpl創建Socket
|
//ConnectionManagerImpl.java
private void createSocket() {
……
// Start the port listener for s2s communication
startServerListener(localIPAddress);
// Start the port listener for external components
startComponentListener(localIPAddress);
// Start the port listener for clients
startClientListeners(localIPAddress);
// Start the port listener for secured clients
startClientSSLListeners(localIPAddress);
}
|
ConnectionManagerImpl開啓socket監聽，啓動SocketAcceptTread線程
|
//ConnectionManagerImpl.java
private void startClientListeners(String localIPAddress) {
……
try {
socketThread = new SocketAcceptThread(this, serverPort);
ports.add(serverPort);
socketThread.setDaemon(true);
socketThread.start();
……
}
catch (Exception e) {
…..
}
}
}
|
SocketAcceptTread啓動過程
|
// SocketAcceptTread.java
public void run() {
while (notTerminated) {
try {
Socket sock = serverSocket.accept();
if (sock != null) {
Log.debug("Connect " + sock.toString());
connManager.addSocket(sock, false, serverPort);
}
}
catch (IOException ie) {
…..
}
…..
}
// 線程結束的時候後面處理關閉serverSocket
……
}
|
當一個Client連接到Server,ConnectionManagerImpl增加一個Socket連接
|
//ConnectionManagerImpl.java
public void addSocket(Socket sock, boolean isSecure, ServerPort serverPort) {
try {
SocketConnection conn = new SocketConnection(deliverer, sock, isSecure);
SocketReader reader = null;
String threadName = null;
if (serverPort.isClientPort()) {
reader = new ClientSocketReader(router, serverName,sock,conn);
threadName = "Client SR";
}
else if (serverPort.isComponentPort()) {
reader = new ComponentSocketReader(router, serverName, sock, conn);
threadName = "Component SR";
}
else {
reader = new ServerSocketReader(router, serverName, sock, conn);
threadName = "Server SR";
}
Thread thread = new Thread(reader, threadName);
thread.setDaemon(true);
thread.start();
}
catch (IOException e) {
Log.error(LocaleUtils.getLocalizedString("admin.error"), e);
}
}
|
ConnectionManagerImpl啓動一個SocketReader線程
|
//SocketReader.java
public void run() {
try {
reader = new XPPPacketReader();
reader.setXPPFactory(factory);
reader.getXPPParser().setInput(new InputStreamReader(socket.getInputStream(),
CHARSET));
// Read in the opening tag and prepare for packet stream
try {
//socketReader啓動的時，需要創建一個Session來負責和Client的會話
createSession();
}
catch (IOException e) {
…..
}
// 會話結束後的處理
if (session != null) {
readStream();
}
}
catch (EOFException eof) {
// Normal disconnect
}
}
|
createSession() 調用abstract方法createSession(String namespace)，這個方法的在不同客戶端的SocketReader中被實現，我們拿ClientSocketReader舉例
|
//ClientSocketReader.java
Boolean createSession(String namespace) …{
if ("jabber:client".equals(namespace)) {
// ClientSession負責創建一個ClientSession
session = ClientSession.createSession(serverName, reader, connection);
return true;
}
return false;
}
|
ClientSeesion創建ClientSeesion的過程
|
//ClientSeesion.java
public static Session createSession(String serverName, XPPPacketReader reader,
SocketConnection connection)
throws XmlPullParserException, UnauthorizedException,IOException{
……
// 爲用戶創建一個Session
Session session = SessionManager.getInstance().createClientSession(connection);
Writer writer = connection.getWriter();
//創建packet response的開頭
……
boolean done = false;
while (!done) {
if (xpp.next() == XmlPullParser.START_TAG) {
done = true;
if (xpp.getName().equals("starttls") &&
xpp.getNamespace(xpp.getPrefix()).equals(TLS_NAMESPACE))
{
writer.write("<proceed xmlns=/"urn:ietf:params:xml:ns:xmpp-tls/"/>");
if (isFlashClient) {
writer.write('/0');
}
writer.flush();
// TODO: setup SSLEngine and negotiate TLS.
}
}
}
return session;}
|
|
//SessionManager.java
public Session createClientSession(Connection conn) throws UnauthorizedException {
if (serverName == null) {
throw new UnauthorizedException("Server not initialized");
}
StreamID id = nextStreamID();
ClientSession session = new ClientSession(serverName, conn, id);
conn.init(session);
// Register to receive close notification on this session so we can
// remove and also send an unavailable presence if it wasn't
// sent before
conn.registerCloseListener(clientSessionListener, session);
// Add to pre-authenticated sessions.
preAuthenticatedSessions.put(session.getAddress().toString(), session);
return session;
}
|
總結一下：
1． ConnectionManagermentImpl初始化啓動
2． ConnectionManagermentImpl創建一個Socket啓動監聽
3． 當客戶端啓動Socket連接， SocketAcceptThread接受客戶端連接
ConnectionManagerImpl調用addSocket，創建一個SocketConnection和SocketReader，並啓動SocketReader線程
4． SocketReader會創建一個用戶會話（Session）