presencesubscribehandler.java

基于Jabber协议的即时消息服务器

/**
 * $RCSfile: PresenceSubscribeHandler.java,v $
 * $Revision: 3136 $
 * $Date: 2005-12-01 02:06:16 -0300 (Thu, 01 Dec 2005) $
 *
 * Copyright (C) 2004 Jive Software. All rights reserved.
 *
 * This software is published under the terms of the GNU Public License (GPL),
 * a copy of which is included in this distribution.
 */

package org.jivesoftware.wildfire.handler;

import org.jivesoftware.util.LocaleUtils;
import org.jivesoftware.util.Log;
import org.jivesoftware.wildfire.*;
import org.jivesoftware.wildfire.container.BasicModule;
import org.jivesoftware.wildfire.roster.Roster;
import org.jivesoftware.wildfire.roster.RosterItem;
import org.jivesoftware.wildfire.roster.RosterManager;
import org.jivesoftware.wildfire.user.UserAlreadyExistsException;
import org.jivesoftware.wildfire.user.UserManager;
import org.jivesoftware.wildfire.user.UserNotFoundException;
import org.xmpp.packet.JID;
import org.xmpp.packet.Packet;
import org.xmpp.packet.PacketError;
import org.xmpp.packet.Presence;

import java.util.Hashtable;
import java.util.List;
import java.util.Map;

/**
 * Implements the presence protocol. Clients use this protocol to
 * update presence and roster information.
 * <p/>
 * The handler must properly detect the presence type, update the user's roster,
 * and inform presence subscribers of the session's updated presence
 * status. Presence serves many purposes in Jabber so this handler will
 * likely be the most complex of all handlers in the server.
 * <p/>
 * There are four basic types of presence updates:
 * <ul>
 * <li>Simple presence updates - addressed to the server (or to address), these updates
 * are properly addressed by the server, and multicast to
 * interested subscribers on the user's roster. An empty, missing,
 * or "unavailable" type attribute indicates a simple update (there
 * is no "available" type although it should be accepted by the server.
 * <li>Directed presence updates - addressed to particular jabber entities,
 * these presence updates are properly addressed and directly delivered
 * to the entity without broadcast to roster subscribers. Any update type
 * is possible except those reserved for subscription requests.
 * <li>Subscription requests - these updates request presence subscription
 * status changes. Such requests always affect the roster.  The server must:
 * <ul>
 * <li>update the roster with the proper subscriber info
 * <li>push the roster changes to the user
 * <li>forward the update to the correct parties.
 * </ul>
 * The valid types include "subscribe", "subscribed", "unsubscribed",
 * and "unsubscribe".
 * <li>XMPPServer probes - Provides a mechanism for servers to query the presence
 * status of users on another server. This allows users to immediately
 * know the presence status of users when they come online rather than way
 * for a presence update broadcast from the other server or tracking them
 * as they are received.  Requires S2S capabilities.
 * </ul>
 * <p/>
 * <h2>Warning</h2>
 * There should be a way of determining whether a session has
 * authorization to access this feature. I'm not sure it is a good
 * idea to do authorization in each handler. It would be nice if
 * the framework could assert authorization policies across channels.
 *
 * @author Iain Shigeoka
 */
public class PresenceSubscribeHandler extends BasicModule implements ChannelHandler {

    private RoutingTable routingTable;
    private XMPPServer localServer;
    private String serverName;
    private PacketDeliverer deliverer;
    private PresenceManager presenceManager;
    private RosterManager rosterManager;
    private UserManager userManager;

    public PresenceSubscribeHandler() {
        super("Presence subscription handler");
    }

    public void process(Packet xmppPacket) throws PacketException {
        Presence presence = (Presence) xmppPacket;
        try {
            JID senderJID = presence.getFrom();
            JID recipientJID = presence.getTo();
            Presence.Type type = presence.getType();

            // Reject presence subscription requests sent to the local server itself.
            if (recipientJID == null || recipientJID.toString().equals(serverName)) {
                if (type == Presence.Type.subscribe) {
                    Presence reply = new Presence();
                    reply.setTo(senderJID);
                    reply.setFrom(recipientJID);
                    reply.setType(Presence.Type.unsubscribed);
                    deliverer.deliver(reply);
                }
                return;
            }

            try {
                Roster senderRoster = getRoster(senderJID);
                if (senderRoster != null) {
                    manageSub(recipientJID, true, type, senderRoster);
                }
                Roster recipientRoster = getRoster(recipientJID);
                boolean recipientSubChanged = false;
                if (recipientRoster != null) {
                    recipientSubChanged = manageSub(senderJID, false, type, recipientRoster);
                }

                // Do not forward the packet to the recipient if the presence is of type subscribed
                // and the recipient user has not changed its subscription state.
                if (!(type == Presence.Type.subscribed && recipientRoster != null &&
                        !recipientSubChanged)) {

                    // If the user is already subscribed to the *local* user's presence then do not 
                    // forward the subscription request and instead send an auto-reply on behalf
                    // of the user
                    if (type == Presence.Type.subscribe && recipientRoster != null &&
                        !recipientSubChanged) {
                        try {
                            RosterItem.SubType subType = recipientRoster.getRosterItem(senderJID)
                                    .getSubStatus();
                            if (subType == RosterItem.SUB_FROM || subType == RosterItem.SUB_BOTH) {
                                // auto-reply by sending a presence stanza of type "subscribed"
                                // to the contact on behalf of the user
                                Presence reply = new Presence();
                                reply.setTo(senderJID);
                                reply.setFrom(recipientJID);
                                reply.setType(Presence.Type.subscribed);
                                deliverer.deliver(reply);
                                return;
                            }
                        }
                        catch (UserNotFoundException e) {
                            // Weird case: Roster item does not exist. Should never happen
                        }
                    }

                    // Try to obtain a handler for the packet based on the routes. If the handler is
                    // a module, the module will be able to handle the packet. If the handler is a
                    // Session the packet will be routed to the client. If a route cannot be found
                    // then the packet will be delivered based on its recipient and sender.
                    List<ChannelHandler> handlers = routingTable.getRoutes(recipientJID);
                    if (!handlers.isEmpty()) {
                        for (ChannelHandler handler : handlers) {
                            Presence presenteToSend = presence.createCopy();
                            // Stamp the presence with the user's bare JID as the 'from' address
                            presenteToSend.setFrom(senderJID.toBareJID());
                            handler.process(presenteToSend);
                        }
                    }
                    else {
                        deliverer.deliver(presence.createCopy());
                    }

                    if (type == Presence.Type.subscribed) {
                        // Send the presence of the local user to the remote user. The remote user
                        // subscribed to the presence of the local user and the local user accepted
                        JID prober = localServer.isLocal(recipientJID) ?
                                new JID(recipientJID.toBareJID()) : recipientJID;
                        presenceManager.probePresence(prober, senderJID);
                    }
                }

                if (type == Presence.Type.unsubscribed) {
                    // Send unavailable presence from all of the local user's available resources
                    // to the remote user
                    presenceManager.sendUnavailableFromSessions(recipientJID, senderJID);
                }
            }
            catch (SharedGroupException e) {
                Presence result = presence.createCopy();
                JID sender = result.getFrom();
                result.setFrom(presence.getTo());
                result.setTo(sender);
                result.setError(PacketError.Condition.not_acceptable);
                deliverer.deliver(result);
            }
        }
        catch (Exception e) {
            Log.error(LocaleUtils.getLocalizedString("admin.error"), e);
        }
    }

    /**
     * <p>Obtain the roster for the given address or null if the address doesn't have a roster.</p>
     *
     * @param address The address to check
     * @return The roster or null if the address is not managed on the server
     */
    private Roster getRoster(JID address) {
        String username;
        Roster roster = null;
        if (localServer.isLocal(address) && userManager.isRegisteredUser(address.getNode())) {
            username = address.getNode();
            try {
                roster = rosterManager.getRoster(username);
            }
            catch (UserNotFoundException e) {
                // Do nothing
            }
        }
        return roster;
    }

    /**
     * Manage the subscription request. This method retrieves a user's roster
     * and updates it's state, storing any changes made, and updating the roster
     * owner if changes occured.
     *
     * @param target    The roster target's jid (the item's jid to be changed)
     * @param isSending True if the request is being sent by the owner
     * @param type      The subscription change type (subscribe, unsubscribe, etc.)
     * @return true if the subscription state has changed.
     */
    private boolean manageSub(JID target, boolean isSending, Presence.Type type, Roster roster)
            throws UserAlreadyExistsException, SharedGroupException
    {
        RosterItem item = null;
        RosterItem.AskType oldAsk;
        RosterItem.SubType oldSub = null;
        RosterItem.RecvType oldRecv;
        boolean newItem = false;
        try {
            if (roster.isRosterItem(target)) {
                item = roster.getRosterItem(target);
            }
            else {
                if (Presence.Type.unsubscribed == type || Presence.Type.unsubscribe == type) {
                    // Do not create a roster item when processing a confirmation of