Asio: very strange problem

29 Nov 2006


      I'm still trying to implement a multithreaded http server with asio: the  
problem I have reported in the past about IOCP looks fixed but now I'm  
falling in another one...If you try the following example it will works  
well with IE6 and Opera 9 but not with Firefox 2.0 (it always detect an  
aborted connection). To make it works with Firefox just uncomment the  
"Sleep(0)". Obiously I don't think that the problem is related to Firefox,  
but I cannot understand why it works well with others browsers...

class Session
{
public:
	Session(boost::asio::io_service &service) : m_socket(service) { }
	~Session() { m_socket.close(); }

	boost::asio::ip::tcp::socket & socket() { return m_socket; }

	void run()
	{
		//Sleep(0);	   // Uncomment this line to make it works in Firefox

		m_socket.async_read_some(boost::asio::buffer(m_buffer),
		boost::bind(&Session::read_handler, this,  
boost::asio::placeholders::error,  
boost::asio::placeholders::bytes_transferred));
	}

	void read_handler(const boost::system::error_code &e, size_t  
bytes_transferred)
	{
		if(!e)
		{
			static int counter = 0;
			std::stringstream stream;
			stream << "<html><body><h2>Hello" << ++counter << "</h2></body></html>";
			m_response = stream.str();
			boost::asio::async_write(m_socket, boost::asio::buffer(m_response),
			boost::bind(&Session::write_handler, this,  
boost::asio::placeholders::error,  
boost::asio::placeholders::bytes_transferred));
		}
	}

	void write_handler(const boost::system::error_code &e, size_t  
bytes_transferred)
	{
		delete this;
	}

private:
	boost::asio::ip::tcp::socket m_socket;
	boost::array<char, 8192> m_buffer;	
	std::string m_response;
};

class Server
{
public:
	Server(int port) : m_service(), m_acceptor(m_service)
	{
		boost::asio::ip::tcp::endpoint endpoint(boost::asio::ip::tcp::v4(),  
port);
		m_acceptor.open(endpoint.protocol());
		m_acceptor.bind(endpoint);
		m_acceptor.listen();
		accept();
	}	

	void accept()
	{
		Session *connection = new Session(m_service);
		m_acceptor.async_accept(connection->socket(),
		boost::bind(&Server::accept_handler, this,  
boost::asio::placeholders::error, connection));	
	}

	void run(int threads = 10)
	{
		boost::thread_group threads_pool;
		while(threads-- > 0)
			threads_pool.create_thread(boost::bind(&boost::asio::io_service::run,  
&m_service));

		m_service.run();		
	}

	void accept_handler(const boost::system::error_code &e, Session  
*connection)
	{
		if(!e)
		{		
			connection->run();		
			accept();
		}
	}

protected:
	boost::asio::io_service m_service;		
	boost::asio::ip::tcp::acceptor m_acceptor;		
};

int main(int argc, char **argv)
{
	Server server(7070);
	server.run();
	return 0;
}

berserker_r

Christopher Kohlhoff

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