openfire client聊天消息交互和存储离线（在线）消息记录策略

【0】如何将离线消息存档，且在接收者上线之后，推送消息到接收者

发送方发送消息 -> 检测接收方是否在线 ->
-> y -> 发送在线消息 -> 发送成功后，存档到消息记录；
-> n -> 修改数据包（XML流） 发送离线消息 ->  存档到消息记录 -> 不断检测某离线消息的接收方是否在线
-> y -> 推送离线消息记录（未读）到 刚刚登陆的离线用户；
-> n -> 继续检测；

【1】消息交互

1）intro： 以下消息内容

是小生我从 smack client 发送消息（hello, abcdefg）和另外一个 client 与的消息交互情况；

2）接收方离线和发送方在线，而后接收方在线的情况

Attention）incoming（true->sender，false->receiver）, processed(true->after processed, false->before processed)

step1）发送msg时，接收者离线；（openfire处理前）

<message to="tangtang@lenovo-pc" id="8akb9-36" type="chat" from="pacoson@lenovo-pc/Smack"><body>hello, abcdefg</body><thread>1d5f0c93-4eb6-4461-a09a-0da6fc9d3ac6</thread></message>
org.jivesoftware.openfire.session.LocalClientSession@1960f3cb status: 3 address: pacoson@lenovo-pc/Smack id: 8vqkiso6gv presence: 
<presence id="8akb9-34" from="pacoson@lenovo-pc/Smack"><c xmlns="http://jabber.org/protocol/caps" hash="sha-1" node="http://www.igniterealtime.org/projects/smack" ver="os2Kusj3WEOivn5n4iFr/ZEO8ls="/>
</presence>
incoming = true, processed = false

step2）发送msg时，接收者离线；（openfire处理后）

<message to="tangtang@lenovo-pc" id="8akb9-36" type="chat" from="pacoson@lenovo-pc/Smack"><body>hello, abcdefg</body><thread>1d5f0c93-4eb6-4461-a09a-0da6fc9d3ac6</thread></message>
org.jivesoftware.openfire.session.LocalClientSession@1960f3cb status: 3 address: pacoson@lenovo-pc/Smack id: 8vqkiso6gv presence: 
<presence id="8akb9-34" from="pacoson@lenovo-pc/Smack"><c xmlns="http://jabber.org/protocol/caps" hash="sha-1" node="http://www.igniterealtime.org/projects/smack" ver="os2Kusj3WEOivn5n4iFr/ZEO8ls="/>
</presence>
incoming = true, processed = true

Attention）

A1）以上就是当发送者在线，而接收者离线的openfire消息记录；

A2）以下是接收者登录后的 openifre 消息记录；

step3）接收者登录在线（openfire处理前）

<message to="tangtang@lenovo-pc" id="8akb9-36" type="chat" from="pacoson@lenovo-pc/Smack"><body>hello, abcdefg</body><thread>1d5f0c93-4eb6-4461-a09a-0da6fc9d3ac6</thread><delay xmlns="urn:xmpp:delay" from="lenovo-pc" stamp="2016-07-18T00:39:29.759Z"/></message>
org.jivesoftware.openfire.session.LocalClientSession@46cc3cbd status: 3 address: tangtang@lenovo-pc/Smack id: 4qrph1nzci presence: 
<presence id="2h2Pk-7" from="tangtang@lenovo-pc/Smack"><c xmlns="http://jabber.org/protocol/caps" hash="sha-1" node="http://www.igniterealtime.org/projects/smack" ver="os2Kusj3WEOivn5n4iFr/ZEO8ls="/>
</presence>
incoming = false, processed = false

step4）接收者登录在线（openfire处理后）

<message to="tangtang@lenovo-pc" id="8akb9-36" type="chat" from="pacoson@lenovo-pc/Smack"><body>hello, abcdefg</body><thread>1d5f0c93-4eb6-4461-a09a-0da6fc9d3ac6</thread><delay xmlns="urn:xmpp:delay" from="lenovo-pc" stamp="2016-07-18T00:39:29.759Z"/></message>
org.jivesoftware.openfire.session.LocalClientSession@46cc3cbd status: 3 address: tangtang@lenovo-pc/Smack id: 4qrph1nzci presence: 
<presence id="2h2Pk-7" from="tangtang@lenovo-pc/Smack"><c xmlns="http://jabber.org/protocol/caps" hash="sha-1" node="http://www.igniterealtime.org/projects/smack" ver="os2Kusj3WEOivn5n4iFr/ZEO8ls="/>
</presence>
incoming = false, processed = true

Conclusion）openfire 对离线消息的处理： 当接收者不在线的时候，openfire 会把 msg 存储到 ofoffline 这个数据库表中；当接收者登录在线后，openfire 会把该消息push 给接收者，因而接收者在线后接受 openfire 推送的离线消息后，会发送响应消息（参见session 的 from 元素值）；之后openfire 会将该消息从 ofoffline 表中清空（即时删除已经发送到用户的离线消息）；

3）接收方和发送方都在线的情况

step1）发送方发送消息（处理前）

<message to="tangtang@lenovo-pc" id="8akb9-76" type="chat" from="pacoson@lenovo-pc/Smack"><body>i am a student.</body><thread>20b6bc6b-64b8-4cc8-a58c-c416090ae1bc</thread></message>
org.jivesoftware.openfire.session.LocalClientSession@647c5490 status: 3 address: pacoson@lenovo-pc/Smack id: 30glj4xlhu presence: 
<presence id="8akb9-72" from="pacoson@lenovo-pc/Smack"><c xmlns="http://jabber.org/protocol/caps" hash="sha-1" node="http://www.igniterealtime.org/projects/smack" ver="os2Kusj3WEOivn5n4iFr/ZEO8ls="/>
</presence>
incoming = true, processed = false

step2）接收方接收消息（处理前）

<message to="tangtang@lenovo-pc" id="8akb9-76" type="chat" from="pacoson@lenovo-pc/Smack"><body>i am a student.</body><thread>20b6bc6b-64b8-4cc8-a58c-c416090ae1bc</thread></message>
org.jivesoftware.openfire.session.LocalClientSession@32e2ab29 status: 3 address: tangtang@lenovo-pc/Smack id: 3t4gvqjm80 presence: 
<presence id="ZvrMI-7" from="tangtang@lenovo-pc/Smack"><c xmlns="http://jabber.org/protocol/caps" hash="sha-1" node="http://www.igniterealtime.org/projects/smack" ver="os2Kusj3WEOivn5n4iFr/ZEO8ls="/>
</presence>
incoming = false, processed = false

step3）接收方接收消息（处理后）

<message to="tangtang@lenovo-pc" id="8akb9-76" type="chat" from="pacoson@lenovo-pc/Smack"><body>i am a student.</body><thread>20b6bc6b-64b8-4cc8-a58c-c416090ae1bc</thread></message>
org.jivesoftware.openfire.session.LocalClientSession@32e2ab29 status: 3 address: tangtang@lenovo-pc/Smack id: 3t4gvqjm80 presence: 
<presence id="ZvrMI-7" from="tangtang@lenovo-pc/Smack"><c xmlns="http://jabber.org/protocol/caps" hash="sha-1" node="http://www.igniterealtime.org/projects/smack" ver="os2Kusj3WEOivn5n4iFr/ZEO8ls="/>
</presence>
incoming = false, processed = true

step4）发送方发送消息（处理后）

<message to="tangtang@lenovo-pc" id="8akb9-76" type="chat" from="pacoson@lenovo-pc/Smack"><body>i am a student.</body><thread>20b6bc6b-64b8-4cc8-a58c-c416090ae1bc</thread></message>
org.jivesoftware.openfire.session.LocalClientSession@647c5490 status: 3 address: pacoson@lenovo-pc/Smack id: 30glj4xlhu presence: 
<presence id="8akb9-72" from="pacoson@lenovo-pc/Smack"><c xmlns="http://jabber.org/protocol/caps" hash="sha-1" node="http://www.igniterealtime.org/projects/smack" ver="os2Kusj3WEOivn5n4iFr/ZEO8ls="/>
</presence>
incoming = true, processed = true

Conclusion）

C1）我们发现，不管是发送在线消息还是离线消息，在openfire 处理前后，都可以对消息进行拦截；

C2）根据以上打印info，我们计划在 incoming = true, processed = true 的case下存储消息记录；

C3） 如果接收方成功接收消息后（incoming = false, processed = true），我们存储在线消息，有且仅在该case下存储消息到 ofchatlog 数据库表；如果没有接收方的响应信息（incoming 始终等于true，即session.jsi 始终是发送者，没有接收者，表明接收者离线），openfire会存储离线消息；当离线的接收者登录后，openfire 推送离线消息给该接收者（参见“2->step3,step4”的交互消息步骤），我们就在 incoming = false, processed = true的case下将该消息转储到到 ofchatlog；

C4）一句话说完，我们的ChatLog 插件涉及的 ofchatlog 数据库表只存储在线消息，而离线消息存储在 ofoffline(owned by openfire)；所以当接收者离线的时候，离线消息不会存储到 ofchatlog，而是会存储到 ofoffline，离线用户登录后，会将消息从 ofoffline 转储到 ofchatlog；

<pre name="code" class="java">public class ChatlogPlugin implements PacketInterceptor, Plugin {private static final Logger log = LoggerFactory.getLogger(ChatlogPlugin.class);private static PluginManager pluginManager;private static ChatlogManager logsManager;// Hook for intercpetornprivate InterceptorManager interceptorManager;private PresencePlugin presencePlugin;public ChatlogPlugin() {interceptorManager = InterceptorManager.getInstance();logsManager = ChatlogManager.getInstance();}/*** <b>function:</b> 拦截消息核心方法，Packet就是拦截消息对象*/@Overridepublic void interceptPacket(Packet packet, Session session,boolean incoming, boolean processed) throws PacketRejectedException {Packet copyPacket = packet.createCopy();if (packet instanceof Message) {Message message = (Message) copyPacket;System.out.println(message.toXML());System.out.println(session);System.out.println("incoming = " + incoming + ", processed = " + processed);if (message.getType() == Message.Type.chat) { // 一对一聊天，单人模式if (!incoming && processed) { // 有且仅在该case下，存储在线消息(或转储离线消息->chatlog 数据库表)logsManager.insert(buildChatlog(packet, incoming, session));} else {return ;}