TeamTalk消息服务器（未读计数）

信令和协议设计

enum MessageCmdID {
   // ...... 省略无关逻辑 
  CID_MSG_UNREAD_CNT_REQUEST = 775,
  CID_MSG_UNREAD_CNT_RESPONSE = 776,
   // ...... 省略无关逻辑 
};

message IMUnreadMsgCntReq{
	//cmd id:		0x0307
	required uint32 user_id = 1;
	optional bytes attach_data = 20;	
}

message IMUnreadMsgCntRsp{
	//cmd id:		0x0308
	required uint32 user_id = 1;
	required uint32 total_cnt = 2; // 多个人的未读消息
	repeated IM.BaseDefine.UnreadInfo unreadinfo_list = 3;
	optional bytes attach_data = 20;
}

message UnreadInfo{
	required uint32 session_id = 1; // 会话ID
	required SessionType session_type = 2; // 会话类型
	required uint32 unread_cnt = 3; // 未读消息数量
	required uint32 latest_msg_id = 4; // 最新的消息ID
	required bytes latest_msg_data = 5; // 最新的消息
    required MsgType latest_msg_type = 6;  // 消息类型
    required uint32 latest_msg_from_user_id = 7;  //发送的用户id
}

流程图：

代码分析

msg_server收到CID_MSG_UNREAD_CNT_REQUEST后调用 CMsgConn::_HandleClientUnreadMsgCntRequest 函数

void CMsgConn::HandlePdu(CImPdu* pPdu)
{
	// ...... 省略无关逻辑 
	switch (pPdu->GetCommandId()) {
         // ...... 省略无关逻辑          
        case CID_MSG_UNREAD_CNT_REQUEST:
            _HandleClientUnreadMsgCntRequest(pPdu );
		break;              
        // ...... 省略无关逻辑 
	}
}

void CMsgConn::_HandleClientUnreadMsgCntRequest(CImPdu* pPdu)
{
	log("HandleClientUnreadMsgCntReq, from_id=%u ", GetUserId());
    IM::Message::IMUnreadMsgCntReq msg;
    CHECK_PB_PARSE_MSG(msg.ParseFromArray(pPdu->GetBodyData(), pPdu->GetBodyLength()));
    
	CDBServConn* pDBConn = get_db_serv_conn_for_login();
	if (pDBConn) {
		CDbAttachData attach(ATTACH_TYPE_HANDLE, m_handle, 0);
        msg.set_user_id(GetUserId());
        msg.set_attach_data(attach.GetBuffer(), attach.GetLength());
        pPdu->SetPBMsg(&msg);
        pDBConn->SendPdu(pPdu);
	}
}

db_proxy_server收到CID_MSG_UNREAD_CNT_REQUEST后调用 DB_PROXY::getUnreadMsgCounter函数

值得注意的是，返回的未读消息里面包含每个会话的未读消息个数，消息类型，最后一条消息。

m_handler_map.insert(make_pair(uint32_t(CID_MSG_UNREAD_CNT_REQUEST), DB_PROXY::getUnreadMsgCounter));

void getUnreadMsgCounter(CImPdu* pPdu, uint32_t conn_uuid)
{
        IM::Message::IMUnreadMsgCntReq msg;
        IM::Message::IMUnreadMsgCntRsp msgResp;
        if(msg.ParseFromArray(pPdu->GetBodyData(), pPdu->GetBodyLength()))
        {
            CImPdu* pPduResp = new CImPdu;

            uint32_t nUserId = msg.user_id();

            list<IM::BaseDefine::UnreadInfo> lsUnreadCount;
            uint32_t nTotalCnt = 0;
            // 从redis获取未读消息数量 和 从mysql获取最后一条未读消息
            CMessageModel::getInstance()->getUnreadMsgCount(nUserId, nTotalCnt, lsUnreadCount);
            CGroupMessageModel::getInstance()->getUnreadMsgCount(nUserId, nTotalCnt, lsUnreadCount);
            msgResp.set_user_id(nUserId);
            msgResp.set_total_cnt(nTotalCnt);
            for(auto it= lsUnreadCount.begin(); it!=lsUnreadCount.end(); ++it)
            {
                IM::BaseDefine::UnreadInfo* pInfo = msgResp.add_unreadinfo_list();
                pInfo->set_session_id(it->session_id());
                pInfo->set_session_type(it->session_type());
                pInfo->set_unread_cnt(it->unread_cnt());
                pInfo->set_latest_msg_id(it->latest_msg_id());
                pInfo->set_latest_msg_data(it->latest_msg_data());
                pInfo->set_latest_msg_type(it->latest_msg_type());
                pInfo->set_latest_msg_from_user_id(it->latest_msg_from_user_id());
            }
                        
            log("userId=%d, unreadCnt=%u, totalCount=%u", nUserId, msgResp.unreadinfo_list_size(), nTotalCnt);
            msgResp.set_attach_data(msg.attach_data());
            pPduResp->SetPBMsg(&msgResp);
            pPduResp->SetSeqNum(pPdu->GetSeqNum());
            pPduResp->SetServiceId(IM::BaseDefine::SID_MSG);
            pPduResp->SetCommandId(IM::BaseDefine::CID_MSG_UNREAD_CNT_RESPONSE);
            CProxyConn::AddResponsePdu(conn_uuid, pPduResp);
        }
        else
        {
            log("parse pb failed");
        }
}

void CMessageModel::getUnreadMsgCount(uint32_t nUserId, uint32_t &nTotalCnt, list<IM::BaseDefine::UnreadInfo>& lsUnreadCount)
{
	// redis
    CacheManager* pCacheManager = CacheManager::getInstance();
    CacheConn* pCacheConn = pCacheManager->GetCacheConn("unread");
    if (pCacheConn)
    {
        map<string, string> mapUnread;
        string strKey = "unread_" + int2string(nUserId);
        bool bRet = pCacheConn->hgetAll(strKey, mapUnread);
        pCacheManager->RelCacheConn(pCacheConn);
        if(bRet)
        {
            IM::BaseDefine::UnreadInfo cUnreadInfo;
            for (auto it = mapUnread.begin(); it != mapUnread.end(); it++) {
                cUnreadInfo.set_session_id(atoi(it->first.c_str()));
                cUnreadInfo.set_unread_cnt(atoi(it->second.c_str()));
                cUnreadInfo.set_session_type(IM::BaseDefine::SESSION_TYPE_SINGLE);
                uint32_t nMsgId = 0;
                string strMsgData;
                IM::BaseDefine::MsgType nMsgType;
                // 从mysql获取最后一条未读消息 mysql
                getLastMsg(cUnreadInfo.session_id(), nUserId, nMsgId, strMsgData, nMsgType); 
                if(IM::BaseDefine::MsgType_IsValid(nMsgType))
                {
                    cUnreadInfo.set_latest_msg_id(nMsgId);
                    cUnreadInfo.set_latest_msg_data(strMsgData);
                    cUnreadInfo.set_latest_msg_type(nMsgType);
                    cUnreadInfo.set_latest_msg_from_user_id(cUnreadInfo.session_id());
                    lsUnreadCount.push_back(cUnreadInfo);
                    nTotalCnt += cUnreadInfo.unread_cnt();
                }
                else
                {
                    log("invalid msgType. userId=%u, peerId=%u, msgType=%u", nUserId, cUnreadInfo.session_id(), nMsgType);
                }
            }
        }
        else
        {
            log("hgetall %s failed!", strKey.c_str());
        }
    }
    else
    {
        log("no cache connection for unread");
    }
}

void CMessageModel::getLastMsg(uint32_t nFromId, uint32_t nToId, uint32_t& nMsgId, string& strMsgData, IM::BaseDefine::MsgType& nMsgType, uint32_t nStatus)
{
    uint32_t nRelateId = CRelationModel::getInstance()->getRelationId(nFromId, nToId, false);
    
    if (nRelateId != INVALID_VALUE)
    {
        CDBManager* pDBManager = CDBManager::getInstance();
        // 读从库
        CDBConn* pDBConn = pDBManager->GetDBConn("teamtalk_slave");
        if (pDBConn)
        {
            string strTableName = "IMMessage_" + int2string(nRelateId % 8);
            string strSql = "select msgId,type,content from " + strTableName + " force index (idx_relateId_status_created) where relateId= " + int2string(nRelateId) + " and status = 0 order by created desc, id desc limit 1";
            CResultSet* pResultSet = pDBConn->ExecuteQuery(strSql.c_str());
            if (pResultSet)
            {
                while (pResultSet->Next())
                {
                    nMsgId = pResultSet->GetInt("msgId");

                    nMsgType = IM::BaseDefine::MsgType(pResultSet->GetInt("type"));
                    if (nMsgType == IM::BaseDefine::MSG_TYPE_SINGLE_AUDIO)
                    {
                        // "[语音]"加密后的字符串
                        strMsgData = strAudioEnc;
                    }
                    else
                    {
                        strMsgData = pResultSet->GetString("content");
                    }
                }
                delete pResultSet;
            }
            else
            {
                log("no result set: %s", strSql.c_str());
            }
            pDBManager->RelDBConn(pDBConn);
        }
        else
        {
            log("no db connection_slave");
        }
    }
    else
    {
        log("no relation between %lu and %lu", nFromId, nToId);
    }
}

db_proxy_server回复信令CID_MSG_UNREAD_CNT_RESPONSE给msg_server，调用CDBServConn::_HandleUnreadMsgCountResponse

void CDBServConn::_HandleUnreadMsgCountResponse(CImPdu* pPdu)
{
    IM::Message::IMUnreadMsgCntRsp msg;
    CHECK_PB_PARSE_MSG(msg.ParseFromArray(pPdu->GetBodyData(), pPdu->GetBodyLength()));

	uint32_t user_id = msg.user_id();
    uint32_t total_cnt = msg.total_cnt();
	uint32_t user_unread_cnt = msg.unreadinfo_list_size();
    CDbAttachData attach_data((uchar_t*)msg.attach_data().c_str(), msg.attach_data().length());
	uint32_t handle = attach_data.GetHandle();
	
	log("HandleUnreadMsgCntResp, userId=%u, total_cnt=%u, user_unread_cnt=%u.", user_id,
        total_cnt, user_unread_cnt);

    CMsgConn* pMsgConn = CImUserManager::GetInstance()->GetMsgConnByHandle(user_id, handle);

	if (pMsgConn && pMsgConn->IsOpen()) {
        msg.clear_attach_data();
        pPdu->SetPBMsg(&msg);
        pMsgConn->SendPdu(pPdu);
	}
}