有时 boost::asio 似乎在我想要它之前断开连接，即在服务器正确处理断开连接之前。我不确定这是怎么可能的，因为客户端似乎认为它完全发送了消息，但是当服务器发出错误时，它甚至没有读取消息头......在测试期间，这可能只发生五分之一，服务器收到客户端关闭消息，并干净地断开客户端。
错误：“现有连接被远程主机强行关闭”
客户端断开连接：
void disconnect()
{
boost::system::error_code error;
//just creates a simple buffer with a shutdown header
boost::uint8_t *packet = createPacket(PC_SHUTDOWN,0);
//sends it
if(!sendBlocking(socket,packet,&error))
{
//didnt get here in my tests, so its not that the write failed...
logWrite(LOG_ERROR,"server",
std::string("Error sending shutdown message.\n")
+ boost::system::system_error(error).what());
}
//actaully disconnect
socket.close();
ioService.stop();
}
bool sendBlocking(boost::asio::ip::tcp::socket &socket,
boost::uint8_t *data, boost::system::error_code* error)
{
//get the length section from the message
boost::uint16_t len = *(boost::uint16_t*)(data - 3);
//send it
asio::write(socket, asio::buffer(data-3,len+3),
asio::transfer_all(), *error);
deletePacket(data);
return !(*error);
}
服务器：
void Client::clientShutdown()
{
//not getting here in problem cases
disconnect();
}
void Client::packetHandler(boost::uint8_t type, boost::uint8_t *data,
boost::uint16_t len, const boost::system::error_code& error)
{
if(error)
{
//error handled here
delete[] data;
std::stringstream ss;
ss << "Error recieving packet.\n";
ss << logInfo() << "\n";
ss << "Error: " << boost::system::system_error(error).what();
logWrite(LOG_ERROR,"Client",ss.str());
disconnect();
}
else
{
//call handlers based on type, most will then call startRead when
//done to get the next packet. Note however, that clientShutdown
//does not
...
}
}
void startRead(boost::asio::ip::tcp::socket &socket, PacketHandler handler)
{
boost::uint8_t *header = new boost::uint8_t[3];
boost::asio::async_read(socket,boost::asio::buffer(header,3),
boost::bind(&handleReadHeader,&socket,handler,header,
boost::asio::placeholders::bytes_transferred,boost::asio::placeholders::error));
}
void handleReadHeader(boost::asio::ip::tcp::socket *socket, PacketHandler handler,
boost::uint8_t *header, size_t len, const boost::system::error_code& error)
{
if(error)
{
//error "thrown" here, len always = 0 in problem cases...
delete[] header;
handler(0,0,0,error);
}
else
{
assert(len == 3);
boost::uint16_t payLoadLen = *((boost::uint16_t*)(header + 0));
boost::uint8_t type = *((boost::uint8_t*) (header + 2));
delete[] header;
boost::uint8_t *payLoad = new boost::uint8_t[payLoadLen];
boost::asio::async_read(*socket,boost::asio::buffer(payLoad,payLoadLen),
boost::bind(&handleReadBody,socket,handler,
type,payLoad,payLoadLen,
boost::asio::placeholders::bytes_transferred,boost::asio::placeholders::error));
}
}
void handleReadBody(ip::tcp::socket *socket, PacketHandler handler,
boost::uint8_t type, boost::uint8_t *payLoad, boost::uint16_t len,
size_t readLen, const boost::system::error_code& error)
{
if(error)
{
delete[] payLoad;
handler(0,0,0,error);
}
else
{
assert(len == readLen);
handler(type,payLoad,len,error);
//delete[] payLoad;
}
}