我需要建立多达三个不同的TCP连接到不同的服务器。所有这三个连接都需要不同的协议,不同的握手和不同的心跳。学习http://www.boost.org/doc/libs/1_61_0/doc/html/boost_asio/example/cpp11/chat/chat_client.cpp,阅读这里的东西,并按照克里斯Kohlhoffs建议我试图执行它如下。boost :: asio和多个客户端连接使用异步
问题是,在这种体系结构中,无论我在做什么,在调用doConnect()中的shared_from_this()时都会收到bad_weak_pointer异常。
Importent这些只是一个未运行的代码片断,它可能包含错误! Importent
我有一个包含一些基本方法的基类。
Connection.h
class Connection : public std::enable_shared_from_this<Connection>
{
public:
//! Ctor
inline Connection();
//! Dtor
inline virtual ~Connection();
inline void setReconnectTime(const long &reconnectAfterMilisec)
{
m_reconnectTime = boost::posix_time::milliseconds(reconnectAfterMilisec);
}
inline void setHandshakePeriod(const long &periodInMilisec)
{
m_handshakePeriod = boost::posix_time::milliseconds(periodInMilisec);
}
virtual void doConnect() = 0;
virtual void stop() = 0;
//... and some view more...
}
我有一个从基类派生那么我的三个等级。这里只有一个(也是核心部分)来描述该方法。
ConnectionA.h
//queues which containing also the age of the messages
typedef std::deque<std::pair<handshakeMsg, boost::posix_time::ptime>> handskMsg_queue;
typedef std::deque<std::pair<errorcodeMsg, boost::posix_time::ptime>> ecMsg_queue;
typedef std::deque<std::pair<A_Msg, boost::posix_time::ptime>> A_Msg_queue;
class ConnectionA : public Connection
{
public:
ConnectionA();
ConnectionA(const std::string& IP, const int &port);
ConnectionA& operator=(const ConnectionA &other);
virtual ~ConnectionA();
virtual void stop() override;
virtual void doConnect() override;
void doPost(std::string &message);
void doHandshake();
void sendErrorCode(const int &ec);
std::shared_ptr<boost::asio::io_service>m_ioS;
private:
std::shared_ptr<tcp::socket> m_socket;
std::shared_ptr<boost::asio::deadline_timer> m_deadlineTimer; // for reconnetions
std::shared_ptr<boost::asio::deadline_timer> m_handshakeTimer; // for heartbeats
void deadlineTimer_handler(const boost::system::error_code& error);
void handshakeTimer_handler(const boost::system::error_code& error);
void doRead();
void doWrite();
std::string m_IP;
int m_port;
handskMsg_queue m_handskMsgQueue;
ecMsg_queue m_ecMsgQueue;
A_Msg_queue m_AMsgQueue;
}
ConnectionA.cpp
ConnectionA::ConnectionA(const std::string &IP, const int &port)
: m_ioS()
, m_socket()
, m_deadlineTimer()
, m_handshakeTimer()
, m_IP(IP)
, m_port(port)
, m_handskMsgQueue(10)
, m_ecMsgQueue(10)
, m_AMsgQueue(10)
{
m_ioS = std::make_shared<boost::asio::io_service>();
m_socket = std::make_shared<tcp::socket>(*m_ioS);
m_deadlineTimer = std::make_shared<boost::asio::deadline_timer>(*m_ioS);
m_handshakeTimer = std::make_shared<boost::asio::deadline_timer> (*m_ioS);
m_deadlineTimer->async_wait(boost::bind(&ConnectionA::deadlineTimer_handler, this, boost::asio::placeholders::error));
m_handshakeTimer->async_wait(boost::bind(&ConnectionA::handshakeTimer_handler, this, boost::asio::placeholders::error));
}
ConnectionA::~ConnectionA()
{}
void ConnectionA::stop()
{
m_ioS->post([this]() { m_socket->close(); });
m_deadlineTimer->cancel();
m_handshakeTimer->cancel();
}
void ConnectionA::doConnect()
{
if (m_socket->is_open()){
return;
}
tcp::resolver resolver(*m_ioS);
std::string portAsString = std::to_string(m_port);
auto endpoint_iter = resolver.resolve({ m_IP.c_str(), portAsString.c_str() });
m_deadlineTimer->expires_from_now(m_reconnectTime);
// this gives me a bad_weak_pointer exception!!!
auto self = std::static_pointer_cast<ConnectionA>(static_cast<ConnectionA*>(this)->shared_from_this());
boost::asio::async_connect(*m_socket, endpoint_iter, [this, self](boost::system::error_code ec, tcp::resolver::iterator){
if (!ec)
{
doHandshake();
doRead();
}
else {
// don't know if async_connect can fail but set the socket to open
if (m_socket->is_open()){
m_socket->close();
}
}
});
}
void ConnectionA::doRead()
{
auto self(shared_from_this());
boost::asio::async_read(*m_socket,
boost::asio::buffer(m_readBuf, m_readBufSize),
[this, self](boost::system::error_code ec, std::size_t){
if(!ec){
// check server answer for errors
}
doRead();
}
else {
stop();
}
});
}
void ConnectionA::doPost(std::string &message)
{
A_Msg newMsg (message);
auto self(shared_from_this());
m_ioS->post([this, self, newMsg](){
bool writeInProgress = false;
if (!m_A_MsgQueue.empty()){
writeInProgress = true;
}
boost::posix_time::ptime currentTime = time_traits_t::now();
m_AMsgQueue.push_back(std::make_pair(newMsg,currentTime));
if (!writeInProgress)
{
doWrite();
}
});
}
void ConnectionA::doWrite()
{
while (!m_AMsgQueue.empty())
{
if (m_AMsgQueue.front().second + m_maxMsgAge < time_traits_t::now()){
m_AMsgQueue.pop_front();
continue;
}
if (!m_socket->is_open()){
continue;
}
auto self(shared_from_this());
boost::asio::async_write(*m_socket,
boost::asio::buffer(m_AMsgQueue.front().first.data(),
m_AMsgQueue.front().first.A_lenght),
[this, self](boost::system::error_code ec, std::size_t /*length*/)
{
if (!ec) // successful
{
m_handshakeTimer->expires_from_now(m_handshakePeriod); // reset timer
m_AMsgQueue.pop_front();
doWrite();
}
else {
if (m_socket->is_open()){
m_socket->close();
}
}
});
}
}
void ConnectionA::deadlineTimer_handler(const boost::system::error_code& error){
if (m_stopped){
return;
}
m_deadlineTimer->async_wait(boost::bind(&ConnectionA::deadlineTimer_handler, this, boost::asio::placeholders::error));
if (!error && !m_socket->is_open()) // timer expired and no connection was established
{
doConnect();
}
else if (!error && m_socket->is_open()){ // timer expired and connection was established
m_deadlineTimer->expires_at(boost::posix_time::pos_infin); // to reactivate timer call doConnect()
}
}
最后也有其封装这些类使其更舒适的使用另一个类:
TcpConnect.h
class CTcpConnect
{
public:
/*! Ctor
*/
CTcpConnect();
//! Dtor
~CTcpConnect();
void initConnectionA(std::string &IP, const int &port);
void initConnectionB(std::string &IP, const int &port);
void initConnectionC(std::string &IP, const int &port);
void postMessageA(std::string &message);
void run();
void stop();
private:
ConnectionA m_AConnection;
ConnectionB m_BConnection;
ConnectionC m_CConnection;
}
TcpConnect.cpp
CTcpConnect::CTcpConnect()
: m_AConnection()
, m_BConnection()
, m_CConnection()
{}
CTcpConnect::~CTcpConnect()
{}
void CTcpConnect::run(){
[this](){ m_AConnection.m_ioS->run(); };
[this](){ m_BConnection.m_ioS->run(); };
[this](){ m_CConnection.m_ioS->run(); };
}
void CTcpConnect::stop(){
m_AConnection.stop();
m_BConnection.stop();
m_CConnection.stop();
}
void CTcpConnect::initConnectionA(std::string &IP, const int &port)
{
m_AConnection = ConnectionA(IP, port);
m_AConnection.setMaxMsgAge(30000);
//... set some view parameter more
m_AConnection.doConnect();
}
// initConnectionB & initConnectionC are quite the same
void CTcpConnect::postMessageA(std::string &message)
{
m_AConnection.doWrite(message);
}
在我尝试也只有一个io_service对象(对于我的做法,这将是罚款)开始,但持有该服务只是作为参考了一些头痛,因为我的实现还需要连接的默认构造函数。现在每个连接都有自己的io服务。
任何想法如何让这段代码运行? 随时为其他架构提出建议。如果你能想出这些,一些片段会更好。我已经在这个实施过程中苦苦挣扎了数周了。我很感激每一个提示。
顺便说一句我用VS12的boost 1.61。
使用asio井是一门艺术。如果我告诉你,asio定时器和套接字不应该被保存在共享指针中,并且io_service引用是一个传递给对象的简单引用,它首先听起来会违反直觉,但这是方式去做吧。通过将shared_from_this()的结果传递给异步处理程序,您的对象可以保持自己和它们的缓冲区处于活动状态。当你要停止对象时,请在所有活动的io对象上调用cancel()。优秀的处理程序将执行指示错误。 –
Tnx为您的建议。我知道我知道,实际上每个人都在说。但问题是,这给你一些限制。然而,阅读这些帖子http://stackoverflow.com/questions/27697973/shared-from-this-causing-bad-weak-ptr和http://stackoverflow.com/questions/29623652/using-boostasioio-service-as -class-member-field我仍然希望将我的方法运行起来。 – GregPhil