Qt项目：基于Qt实现的网络聊天室---TCP服务器和token验证

本篇完成的模块是TCP服务器的设计和token验证

TCP服务器设计

客户端TCP管理者

因为聊天服务要维持一个长链接，方便服务器和客户端双向通信，那么就需要一个TCPMgr来管理TCP连接

而实际开发中网络模块一般以单例模式使用，那我们就基于单例基类和可被分享类创建一个自定义的TcpMgr类，在QT工程中新建TcpMgr类，会生成头文件和源文件，头文件修改如下

#ifndef TCPMGR_H
#define TCPMGR_H
#include <QTcpSocket>
#include "singleton.h"
#include "global.h"
class TcpMgr:public QObject, public Singleton<TcpMgr>,public std::enable_shared_from_this<TcpMgr>
{Q_OBJECT
public:TcpMgr();
private:QTcpSocket _socket;QString _host;uint16_t _port;QByteArray _buffer;bool _b_recv_pending;quint16 _message_id;quint16 _message_len;
public slots:void slot_tcp_connect(ServerInfo);void slot_send_data(ReqId reqId, QString data);
signals:void sig_con_success(bool bsuccess);void sig_send_data(ReqId reqId, QString data);
};#endif // TCPMGR_H

接下来我们在构造函数中连接网络请求的各种信号

TcpMgr::TcpMgr():_host(""),_port(0),_b_recv_pending(false),_message_id(0),_message_len(0)
{QObject::connect(&_socket, &QTcpSocket::connected, [&]() {qDebug() << "Connected to server!";// 连接建立后发送消息emit sig_con_success(true);});QObject::connect(&_socket, &QTcpSocket::readyRead, [&]() {// 当有数据可读时，读取所有数据// 读取所有数据并追加到缓冲区_buffer.append(_socket.readAll());QDataStream stream(&_buffer, QIODevice::ReadOnly);stream.setVersion(QDataStream::Qt_5_0);forever {//先解析头部if(!_b_recv_pending){// 检查缓冲区中的数据是否足够解析出一个消息头（消息ID + 消息长度）if (_buffer.size() < static_cast<int>(sizeof(quint16) * 2)) {return; // 数据不够，等待更多数据}// 预读取消息ID和消息长度，但不从缓冲区中移除stream >> _message_id >> _message_len;//将buffer 中的前四个字节移除_buffer = _buffer.mid(sizeof(quint16) * 2);// 输出读取的数据qDebug() << "Message ID:" << _message_id << ", Length:" << _message_len;}//buffer剩余长读是否满足消息体长度，不满足则退出继续等待接受if(_buffer.size() < _message_len){_b_recv_pending = true;return;}_b_recv_pending = false;// 读取消息体QByteArray messageBody = _buffer.mid(0, _message_len);qDebug() << "receive body msg is " << messageBody ;_buffer = _buffer.mid(_message_len);}});// 处理错误（适用于Qt 5.15之前的版本）QObject::connect(&_socket, static_cast<void (QTcpSocket::*)(QTcpSocket::SocketError)>(&QTcpSocket::error),[&](QTcpSocket::SocketError socketError) {qDebug() << "Error:" << _socket.errorString() ;switch (socketError) {case QTcpSocket::ConnectionRefusedError:qDebug() << "Connection Refused!";emit sig_con_success(false);break;case QTcpSocket::RemoteHostClosedError:qDebug() << "Remote Host Closed Connection!";break;case QTcpSocket::HostNotFoundError:qDebug() << "Host Not Found!";emit sig_con_success(false);break;case QTcpSocket::SocketTimeoutError:qDebug() << "Connection Timeout!";emit sig_con_success(false);break;case QTcpSocket::NetworkError:qDebug() << "Network Error!";break;default:qDebug() << "Other Error!";break;}});// 处理连接断开QObject::connect(&_socket, &QTcpSocket::disconnected, [&]() {qDebug() << "Disconnected from server.";});QObject::connect(this, &TcpMgr::sig_send_data, this, &TcpMgr::slot_send_data);
}

连接对端服务器

void TcpMgr::slot_tcp_connect(ServerInfo si)
{qDebug()<< "receive tcp connect signal";// 尝试连接到服务器qDebug() << "Connecting to server...";_host = si.Host;_port = static_cast<uint16_t>(si.Port.toUInt());_socket.connectToHost(si.Host, _port);
}

因为客户端发送数据可能在任何线程，为了保证线程安全，我们在要发送数据时发送TcpMgr的sig_send_data信号，然后实现接受这个信号的槽函数

void TcpMgr::slot_send_data(ReqId reqId, QString data)
{uint16_t id = reqId;// 将字符串转换为UTF-8编码的字节数组QByteArray dataBytes = data.toUtf8();// 计算长度（使用网络字节序转换）quint16 len = static_cast<quint16>(data.size());// 创建一个QByteArray用于存储要发送的所有数据QByteArray block;QDataStream out(&block, QIODevice::WriteOnly);// 设置数据流使用网络字节序out.setByteOrder(QDataStream::BigEndian);// 写入ID和长度out << id << len;// 添加字符串数据block.append(data);// 发送数据_socket.write(block);
}

然后修改LoginDialog中的initHandlers中的收到服务器登陆回复后的逻辑，这里发送信号准备发起长链接到聊天服务器

void LoginDialog::initHttpHandlers()
{//注册获取登录回包逻辑_handlers.insert(ReqId::ID_LOGIN_USER, [this](QJsonObject jsonObj){int error = jsonObj["error"].toInt();if(error != ErrorCodes::SUCCESS){showTip(tr("参数错误"),false);enableBtn(true);return;}auto user = jsonObj["user"].toString();//发送信号通知tcpMgr发送长链接ServerInfo si;si.Uid = jsonObj["uid"].toInt();si.Host = jsonObj["host"].toString();si.Port = jsonObj["port"].toString();si.Token = jsonObj["token"].toString();_uid = si.Uid;_token = si.Token;qDebug()<< "user is " << user << " uid is " << si.Uid <<" host is "<< si.Host << " Port is " << si.Port << " Token is " << si.Token;emit sig_connect_tcp(si);});
}

在LoginDialog构造函数中连接信号，包括建立tcp连接，以及收到TcpMgr连接成功或者失败的信号处理

//连接tcp连接请求的信号和槽函数connect(this, &LoginDialog::sig_connect_tcp, TcpMgr::GetInstance().get(), &TcpMgr::slot_tcp_connect);
//连接tcp管理者发出的连接成功信号
connect(TcpMgr::GetInstance().get(), &TcpMgr::sig_con_success, this, &LoginDialog::slot_tcp_con_finish);

LoginDialog收到连接结果的槽函数

void LoginDialog::slot_tcp_con_finish(bool bsuccess)
{if(bsuccess){showTip(tr("聊天服务连接成功，正在登录..."),true);QJsonObject jsonObj;jsonObj["uid"] = _uid;jsonObj["token"] = _token;QJsonDocument doc(jsonObj);QString jsonString = doc.toJson(QJsonDocument::Indented);//发送tcp请求给chat serverTcpMgr::GetInstance()->sig_send_data(ReqId::ID_CHAT_LOGIN, jsonString);}else{showTip(tr("网络异常"),false);enableBtn(true);}}

在这个槽函数中我们发送了sig_send_data信号并且通知TcpMgr将数据发送给服务器。

ChatServer

一个TCP服务器必然会有连接的接收，维持，收发数据等逻辑。那我们就要基于asio完成这个服务的搭建。主服务是这个样子的

#include "LogicSystem.h"
#include <csignal>
#include <thread>
#include <mutex>
#include "AsioIOServicePool.h"
#include "CServer.h"
#include "ConfigMgr.h"
using namespace std;
bool bstop = false;
std::condition_variable cond_quit;
std::mutex mutex_quit;int main()
{try {auto &cfg = ConfigMgr::Inst();auto pool = AsioIOServicePool::GetInstance();boost::asio::io_context  io_context;boost::asio::signal_set signals(io_context, SIGINT, SIGTERM);signals.async_wait([&io_context, pool](auto, auto) {io_context.stop();pool->Stop();});auto port_str = cfg["SelfServer"]["Port"];CServer s(io_context, atoi(port_str.c_str()));io_context.run();}catch (std::exception& e) {std::cerr << "Exception: " << e.what() << endl;}}

CServer类的声明

#include <boost/asio.hpp>
#include "CSession.h"
#include <memory.h>
#include <map>
#include <mutex>
using namespace std;
using boost::asio::ip::tcp;
class CServer
{
public:CServer(boost::asio::io_context& io_context, short port);~CServer();void ClearSession(std::string);
private:void HandleAccept(shared_ptr<CSession>, const boost::system::error_code & error);void StartAccept();boost::asio::io_context &_io_context;short _port;tcp::acceptor _acceptor;std::map<std::string, shared_ptr<CSession>> _sessions;std::mutex _mutex;
};

构造函数中监听对方连接

CServer::CServer(boost::asio::io_context& io_context, short port):_io_context(io_context), _port(port),
_acceptor(io_context, tcp::endpoint(tcp::v4(),port))
{cout << "Server start success, listen on port : " << _port << endl;StartAccept();
}

接受连接的函数

void CServer::StartAccept() {auto &io_context = AsioIOServicePool::GetInstance()->GetIOService();shared_ptr<CSession> new_session = make_shared<CSession>(io_context, this);_acceptor.async_accept(new_session->GetSocket(), std::bind(&CServer::HandleAccept, this, new_session, placeholders::_1));
}

AsioIOServicePool

从AsioIOServicePool中返回一个可用的iocontext构造Session，然后将接受的新链接的socket写入这个Session保管

AsioIOServicePool已经在前面讲解很多次了，它的声明如下

#include <vector>
#include <boost/asio.hpp>
#include "Singleton.h"
class AsioIOServicePool:public Singleton<AsioIOServicePool>
{friend Singleton<AsioIOServicePool>;
public:using IOService = boost::asio::io_context;using Work = boost::asio::io_context::work;using WorkPtr = std::unique_ptr<Work>;~AsioIOServicePool();AsioIOServicePool(const AsioIOServicePool&) = delete;AsioIOServicePool& operator=(const AsioIOServicePool&) = delete;// 使用 round-robin 的方式返回一个 io_serviceboost::asio::io_context& GetIOService();void Stop();
private:AsioIOServicePool(std::size_t size = std::thread::hardware_concurrency());std::vector<IOService> _ioServices;std::vector<WorkPtr> _works;std::vector<std::thread> _threads;std::size_t                        _nextIOService;
};

AsioIOServicePool具体实现

#include "AsioIOServicePool.h"
#include <iostream>
using namespace std;
AsioIOServicePool::AsioIOServicePool(std::size_t size):_ioServices(size),
_works(size), _nextIOService(0){for (std::size_t i = 0; i < size; ++i) {_works[i] = std::unique_ptr<Work>(new Work(_ioServices[i]));}//遍历多个ioservice，创建多个线程，每个线程内部启动ioservicefor (std::size_t i = 0; i < _ioServices.size(); ++i) {_threads.emplace_back([this, i]() {_ioServices[i].run();});}
}AsioIOServicePool::~AsioIOServicePool() {std::cout << "AsioIOServicePool destruct" << endl;
}boost::asio::io_context& AsioIOServicePool::GetIOService() {auto& service = _ioServices[_nextIOService++];if (_nextIOService == _ioServices.size()) {_nextIOService = 0;}return service;
}void AsioIOServicePool::Stop(){//因为仅仅执行work.reset并不能让iocontext从run的状态中退出//当iocontext已经绑定了读或写的监听事件后，还需要手动stop该服务for (auto& work : _works) {//把服务先停止work->get_io_context().stop();work.reset();}for (auto& t : _threads) {t.join();}
}

CServer的处理连接逻辑

void CServer::HandleAccept(shared_ptr<CSession> new_session, const boost::system::error_code& error){if (!error) {new_session->Start();lock_guard<mutex> lock(_mutex);_sessions.insert(make_pair(new_session->GetUuid(), new_session));}else {cout << "session accept failed, error is " << error.what() << endl;}StartAccept();
}

Session层

上面的逻辑接受新链接后执行Start函数，新链接接受数据，然后Server继续监听新的连接

void CSession::Start(){AsyncReadHead(HEAD_TOTAL_LEN);
}

先读取头部数据

void CSession::AsyncReadHead(int total_len)
{auto self = shared_from_this();asyncReadFull(HEAD_TOTAL_LEN, [self, this](const boost::system::error_code& ec, std::size_t bytes_transfered) {try {if (ec) {std::cout << "handle read failed, error is " << ec.what() << endl;Close();_server->ClearSession(_uuid);return;}if (bytes_transfered < HEAD_TOTAL_LEN) {std::cout << "read length not match, read [" << bytes_transfered << "] , total ["<< HEAD_TOTAL_LEN << "]" << endl;Close();_server->ClearSession(_uuid);return;}_recv_head_node->Clear();memcpy(_recv_head_node->_data, _data, bytes_transfered);//获取头部MSGID数据short msg_id = 0;memcpy(&msg_id, _recv_head_node->_data, HEAD_ID_LEN);//网络字节序转化为本地字节序msg_id = boost::asio::detail::socket_ops::network_to_host_short(msg_id);std::cout << "msg_id is " << msg_id << endl;//id非法if (msg_id > MAX_LENGTH) {std::cout << "invalid msg_id is " << msg_id << endl;_server->ClearSession(_uuid);return;}short msg_len = 0;memcpy(&msg_len, _recv_head_node->_data + HEAD_ID_LEN, HEAD_DATA_LEN);//网络字节序转化为本地字节序msg_len = boost::asio::detail::socket_ops::network_to_host_short(msg_len);std::cout << "msg_len is " << msg_len << endl;//id非法if (msg_len > MAX_LENGTH) {std::cout << "invalid data length is " << msg_len << endl;_server->ClearSession(_uuid);return;}_recv_msg_node = make_shared<RecvNode>(msg_len, msg_id);AsyncReadBody(msg_len);}catch (std::exception& e) {std::cout << "Exception code is " << e.what() << endl;}});
}

上面的逻辑里调用asyncReadFull读取整个长度，然后解析收到的数据，前两个字节为id，之后两个字节为长度，最后n个长度字节为消息内容

//读取完整长度
void CSession::asyncReadFull(std::size_t maxLength, std::function<void(const boost::system::error_code&, std::size_t)> handler )
{::memset(_data, 0, MAX_LENGTH);asyncReadLen(0, maxLength, handler);
}

读取指定长度

//读取指定字节数
void CSession::asyncReadLen(std::size_t read_len, std::size_t total_len, std::function<void(const boost::system::error_code&, std::size_t)> handler)
{auto self = shared_from_this();_socket.async_read_some(boost::asio::buffer(_data + read_len, total_len-read_len),[read_len, total_len, handler, self](const boost::system::error_code& ec, std::size_t  bytesTransfered) {if (ec) {// 出现错误，调用回调函数handler(ec, read_len + bytesTransfered);return;}if (read_len + bytesTransfered >= total_len) {//长度够了就调用回调函数handler(ec, read_len + bytesTransfered);return;}// 没有错误，且长度不足则继续读取self->asyncReadLen(read_len + bytesTransfered, total_len, handler);});
}

读取头部成功后，其回调函数内部调用了读包体的逻辑

void CSession::AsyncReadBody(int total_len)
{auto self = shared_from_this();asyncReadFull(total_len, [self, this, total_len](const boost::system::error_code& ec, std::size_t bytes_transfered) {try {if (ec) {std::cout << "handle read failed, error is " << ec.what() << endl;Close();_server->ClearSession(_uuid);return;}if (bytes_transfered < total_len) {std::cout << "read length not match, read [" << bytes_transfered << "] , total ["<< total_len<<"]" << endl;Close();_server->ClearSession(_uuid);return;}memcpy(_recv_msg_node->_data , _data , bytes_transfered);_recv_msg_node->_cur_len += bytes_transfered;_recv_msg_node->_data[_recv_msg_node->_total_len] = '\0';cout << "receive data is " << _recv_msg_node->_data << endl;//此处将消息投递到逻辑队列中LogicSystem::GetInstance()->PostMsgToQue(make_shared<LogicNode>(shared_from_this(), _recv_msg_node));//继续监听头部接受事件AsyncReadHead(HEAD_TOTAL_LEN);}catch (std::exception& e) {std::cout << "Exception code is " << e.what() << endl;}});
}

读取包体完成后，在回调中继续读包头。以此循环往复直到读完所有数据。如果对方不发送数据，则回调函数就不会触发。不影响程序执行其他工作，因为我们采用的是asio异步的读写操作

当然我们解析完包体后会调用LogicSystem单例将解析好的消息封装为逻辑节点传递给逻辑层进行处理

LogicSystem

我们在逻辑层处理

void LogicSystem::RegisterCallBacks() {_fun_callbacks[MSG_CHAT_LOGIN] = std::bind(&LogicSystem::LoginHandler, this,placeholders::_1, placeholders::_2, placeholders::_3);
}void LogicSystem::LoginHandler(shared_ptr<CSession> session, const short &msg_id, const string &msg_data) {Json::Reader reader;Json::Value root;reader.parse(msg_data, root);std::cout << "user login uid is  " << root["uid"].asInt() << " user token  is "<< root["token"].asString() << endl;std::string return_str = root.toStyledString();session->Send(return_str, msg_id);
}

并在构造函数中注册这些处理流程

LogicSystem::LogicSystem():_b_stop(false){RegisterCallBacks();_worker_thread = std::thread (&LogicSystem::DealMsg, this);
}

总结

到此，完成了ChatServer收到QT客户端发送过来的长链接请求，并解析读取的数据，将收到的数据通过tcp发送给对端

token验证模块

完善proto

在proto文件里新增登陆验证服务

message LoginReq{int32 uid = 1;string token= 2;
}message LoginRsp {int32 error = 1;int32 uid = 2;string token = 3;
}service StatusService {rpc GetChatServer (GetChatServerReq) returns (GetChatServerRsp) {}rpc Login(LoginReq) returns(LoginRsp);
}

接下来是调用grpc命令生成新的pb文件覆盖原有的，并且也拷贝给StatusServer一份

我们完善登陆逻辑，先去StatusServer验证token是否合理，如果合理再从内存中寻找用户信息，如果没找到则从数据库加载一份

void LogicSystem::LoginHandler(shared_ptr<CSession> session, const short &msg_id, const string &msg_data) {Json::Reader reader;Json::Value root;reader.parse(msg_data, root);auto uid = root["uid"].asInt();std::cout << "user login uid is  " << uid << " user token  is "<< root["token"].asString() << endl;//从状态服务器获取token匹配是否准确auto rsp = StatusGrpcClient::GetInstance()->Login(uid, root["token"].asString());Json::Value  rtvalue;Defer defer([this, &rtvalue, session]() {std::string return_str = rtvalue.toStyledString();session->Send(return_str, MSG_CHAT_LOGIN_RSP);});rtvalue["error"] = rsp.error();if (rsp.error() != ErrorCodes::Success) {return;}//内存中查询用户信息auto find_iter = _users.find(uid);std::shared_ptr<UserInfo> user_info = nullptr;if (find_iter == _users.end()) {//查询数据库user_info = MysqlMgr::GetInstance()->GetUser(uid);if (user_info == nullptr) {rtvalue["error"] = ErrorCodes::UidInvalid;return;}_users[uid] = user_info;}else {user_info = find_iter->second;}rtvalue["uid"] = uid;rtvalue["token"] = rsp.token();rtvalue["name"] = user_info->name;
}

StatusServer验证token

在StatusServer验证token之前，我们需要在StatusServer中的GetServer的服务里将token写入内存

Status StatusServiceImpl::GetChatServer(ServerContext* context, const GetChatServerReq* request, GetChatServerRsp* reply)
{std::string prefix("llfc status server has received :  ");const auto& server = getChatServer();reply->set_host(server.host);reply->set_port(server.port);reply->set_error(ErrorCodes::Success);reply->set_token(generate_unique_string());insertToken(request->uid(), reply->token());return Status::OK;
}

接下来我们实现登陆验证服务

Status StatusServiceImpl::Login(ServerContext* context, const LoginReq* request, LoginRsp* reply)
{auto uid = request->uid();auto token = request->token();std::lock_guard<std::mutex> guard(_token_mtx);auto iter = _tokens.find(uid);if (iter == _tokens.end()) {reply->set_error(ErrorCodes::UidInvalid);return Status::OK;}if (iter->second != token) {reply->set_error(ErrorCodes::TokenInvalid);return Status::OK;}reply->set_error(ErrorCodes::Success);reply->set_uid(uid);reply->set_token(token);return Status::OK;
}

这样当GateServer访问StatusServer的Login服务做验证后，就可以将数据返回给QT前端了

客户端处理登陆回包

QT 的客户端TcpMgr收到请求后要进行对应的逻辑处理。所以我们在TcpMgr的构造函数中调用initHandlers注册消息

void TcpMgr::initHandlers()
{//auto self = shared_from_this();_handlers.insert(ID_CHAT_LOGIN_RSP, [this](ReqId id, int len, QByteArray data){qDebug()<< "handle id is "<< id << " data is " << data;// 将QByteArray转换为QJsonDocumentQJsonDocument jsonDoc = QJsonDocument::fromJson(data);// 检查转换是否成功if(jsonDoc.isNull()){qDebug() << "Failed to create QJsonDocument.";return;}QJsonObject jsonObj = jsonDoc.object();if(!jsonObj.contains("error")){int err = ErrorCodes::ERR_JSON;qDebug() << "Login Failed, err is Json Parse Err" << err ;emit sig_login_failed(err);return;}int err = jsonObj["error"].toInt();if(err != ErrorCodes::SUCCESS){qDebug() << "Login Failed, err is " << err ;emit sig_login_failed(err);return;}UserMgr::GetInstance()->SetUid(jsonObj["uid"].toInt());UserMgr::GetInstance()->SetName(jsonObj["name"].toString());UserMgr::GetInstance()->SetToken(jsonObj["token"].toString());emit sig_swich_chatdlg();});
}

并且增加处理请求

void TcpMgr::handleMsg(ReqId id, int len, QByteArray data)
{auto find_iter =  _handlers.find(id);if(find_iter == _handlers.end()){qDebug()<< "not found id ["<< id << "] to handle";return ;}find_iter.value()(id,len,data);
}

用户管理

为管理用户数据，需要创建一个UserMgr类，统一管理用户数据，我们这么声明

#ifndef USERMGR_H
#define USERMGR_H
#include <QObject>
#include <memory>
#include <singleton.h>class UserMgr:public QObject,public Singleton<UserMgr>,public std::enable_shared_from_this<UserMgr>
{Q_OBJECT
public:friend class Singleton<UserMgr>;~ UserMgr();void SetName(QString name);void SetUid(int uid);void SetToken(QString token);
private:UserMgr();QString _name;QString _token;int _uid;
};#endif // USERMGR_H

简单实现几个功能

#include "usermgr.h"UserMgr::~UserMgr()
{}void UserMgr::SetName(QString name)
{_name = name;
}void UserMgr::SetUid(int uid)
{_uid = uid;
}void UserMgr::SetToken(QString token)
{_token = token;
}UserMgr::UserMgr()
{}

详细和复杂的管理后续不断往这里补充就行了

登陆界面

登陆界面响应TcpMgr返回的登陆请求，在其构造函数中添加

   //连接tcp管理者发出的登陆失败信号connect(TcpMgr::GetInstance().get(), &TcpMgr::sig_login_failed, this, &LoginDialog::slot_login_failed);

并实现槽函数

void LoginDialog::slot_login_failed(int err)
{QString result = QString("登录失败, err is %1").arg(err);showTip(result,false);enableBtn(true);
}

到此完成了登陆的请求和响应，接下来要实现响应登陆成功后跳转到聊天界面。下一篇先实现聊天布局。