Boost Buffer trouble String - c++

Question

I'm having troubles wiith socket and packets... Let me explain it
When a client send "Se|Bla|Blu", the output is "Re|Bla|Blu", like I want, but the problem is, that in the consol server, the output is "DataAsString = Se|Bla|BluouhWe are here now Noooo".
So we can see that it doesn't printthe "I am here" in writeAsync(), so we can assume that there is an error, and this is what I want to fix, the pop-up means :
Debug Assertion Failed!
Program: C:\Windows\system32\MSVCP120D.dll File: c:\program files
(x86)\microsoft visual studio 12.0\vc\include\xstring Line: 79
Expression: string iterator not deferencable
For information on how your program can cause an assertion failure,
see the visual C++ documentation on asserts.
(Press Retry to debug the application) [Abandon] [Retry] [ignore]
I tried to debug it, but no way, I don't know where the problem comes from. Any idea ?
Maybe the buffer doesn't allow string ? Maybe I have to reinitialize dataAsString and m_dataToRead to "" just after ?
Thanks in advance, see you.
Edit : The complete :
#include <boost/asio.hpp>
#include <boost/algorithm/string/split.hpp>
#include <boost/algorithm/string.hpp>
#include <cstdlib>
#include <string>
#include <vector>
#include <iostream>
#include <memory>
#include <utility>
#include "../configuration/constantes.h"
class client : public std::enable_shared_from_this<client>
{
public:
client(boost::asio::ip::tcp::socket socket) : m_socket(std::move(socket)){}
void start()
{
readAsync();
}
private:
void readAsync()
{
auto self(shared_from_this());
m_socket.async_read_some(boost::asio::buffer(m_dataToRead, 512), [this, self](boost::system::error_code error, std::size_t length)
{
if (!error)
{
packetsTreating(m_dataToRead, length);
}
start();
});
}
void writeAsync(std::string m_dataToSend, size_t length)
{
auto self(shared_from_this());
boost::asio::async_write(m_socket, boost::asio::buffer(m_dataToSend, length), [this, self](boost::system::error_code error, std::size_t)
{
if (!error)
{
std::cout << "I am here";
start();
}
});
}
void speak(std::string channel, std::string object)
{
std::cout << "Bouh";
packetLength = 2 + sizeof(canal) + sizeof(objet);
std::cout << "We are here now";
writeAsync(("Re|" + channel + "|" + object), packetLength);
std::cout << "Noooo";
}
void logIn(std::string id, std::string wp)
{
}
void logOut(std::string whatDC)
{
}
void packetsTreating(char* data, size_t length)
{
std::string dataAsString;
dataAsString.assign(data, length);
std::cout << "DataAsString = " << dataAsString;
std::vector<std::string> fields;
boost::split(fields, dataAsString, boost::is_any_of("|"));
if (fields[0] == "Co" && fields.size() == 3)
logIn(fields[1], fields[2]);
else if (fields[0] == "Dc" && fields.size() == 2)
logOut(fields[1]);
else if (fields[0] == "Se" && fields.size() == 3)
speak(fields[1], fields[2]);
else
std::cout << "Unknown command." << std::endl;
}
size_t packetLength = 0;
boost::asio::ip::tcp::socket m_socket;
char m_dataToRead[512];
};
class server
{
public:
server(boost::asio::io_service& ios, short port) : m_acceptor(ios, boost::asio::ip::tcp::endpoint(boost::asio::ip::tcp::v4(), port)), m_socket(ios)
{
acceptConnection();
}
private:
void acceptConnection()
{
m_acceptor.async_accept(m_socket, [this](boost::system::error_code error)
{
if (!error && connectedPerso <= maxConnec) // maxConnec is in constantes.h, = 250
{
connectedPerso++; // Btw, do you know how to -- it when a client disconnect ?
std::cout << "Connection, there is " << connectedPerso << " clients." << std::endl;
std::make_shared<client>(std::move(m_socket))->start();
}
acceptConnection();
});
}
unsigned short connectedPerso = 0;
boost::asio::ip::tcp::acceptor m_acceptor;
boost::asio::ip::tcp::socket m_socket;
};
void main()
{
try
{
std::cout << "TCP open on port " << port << ". maxConnec is " << maxConnec << "." << std::endl;
boost::asio::io_service iosConnector;
serveur serveur(iosConnector, port); // port = 2013
iosConnector.run();
}
catch (std::exception& e)
{
std::cerr << "Exception : " << e.what() << "\n";
}
}

Answer 1

There is a logic error. You are calling start() from both the sync write handler and the sync read handler. Since start() calls async_read on the socket, you will end up having 2 active async reads on the socket after the first write. This is illegal.

Answer 2

answer supplied to demonstrate that the code you posted seemed to work on my system:
$ telnet localhost 2013
Trying 127.0.0.1...
Connected to localhost.
Escape character is '^]'.
hello
hello
ccccc
Re|1|hello|
Se|channel|text
Re|channel|text
Se|channel|text
Re|channel|text
Se|channel|text
Re|channel|text
^]
telnet> close
Connection closed.
stdout:
Connection, there is 1 clients.
DataAsString = hello
Unknown command.
DataAsString = hello
Unknown command.
DataAsString = ccccc
Unknown command.
DataAsString = Re|1|hello|
Unknown command.
DataAsString = Se|channel|text
BouhWe are here nowNooooI am hereDataAsString = Se|channel|text
BouhWe are here nowNooooI am hereDataAsString = Se|channel|text