async_read doesn't read data sent from telnet - c++

Question

This is my current code for the server. I connect to the server using telnet.
#include <cstdlib>
#include <iostream>
#include <boost/bind.hpp>
#include <boost/asio.hpp>
using boost::asio::ip::tcp;
class Connection
{
public:
Connection(boost::asio::io_service& io_service) : socket_(io_service)
{
}
void start()
{
AsyncRead();
}
tcp::socket& socket()
{
return socket_;
}
private:
void AsyncRead()
{
boost::asio::async_read(socket_, boost::asio::buffer(data_, max_length),
[this](boost::system::error_code ec, std::size_t length)
{
if (!ec)
{
std::cout << data_ << std::endl;
}
});
}
tcp::socket socket_;
enum { max_length = 1024 };
char data_[max_length];
};
class server
{
public:
server(boost::asio::io_service& io_service, short port)
: io_service_(io_service),
acceptor_(io_service, tcp::endpoint(tcp::v4(), port))
{
start_accept();
}
private:
void start_accept()
{
Connection* connection = new Connection(io_service_);
acceptor_.async_accept(connection->socket(), [this, connection](boost::system::error_code ec)
{
//std::cout << ec.message() << std::endl;
if(!ec)
{
std::cout << "Connected." << std::endl;
connection->start();
}
else
{
delete connection;
}
start_accept();
});
}
boost::asio::io_service& io_service_;
tcp::acceptor acceptor_;
};
int main(int argc, char* argv[])
{
try
{
boost::asio::io_service io_service;
server s(io_service, 7899);
io_service.run();
}
catch (std::exception& e)
{
std::cerr << "Exception: " << e.what() << "\n";
}
return 0;
}
Instead of async_read I use async_read_some I can get the first message sent from telnet and thats it.
Any suggestions on what I am doing wrong ?
Thanks.

Answer 1

async_read will read the number of bytes specified in the length parameter. You aren't seeing the first message because async_read is still waiting to read max_length bytes. This question discusses similar behaviour