#include <cstdlib>
#include <iostream>
#include <boost/bind.hpp>
#include <boost/smart_ptr.hpp>
#include <boost/asio.hpp>
#include <boost/thread.hpp>
#include <boost/regex.hpp>
#include <boost/lexical_cast.hpp>
#include <string>
using boost::asio::ip::tcp;
const int max_length = 1000000;
typedef boost::shared_ptr<tcp::socket> socket_ptr;
unsigned short analyze_user_request(std::string& user_request, short unsigned* ID, std::string* request_value)
{
// function returns:
// 0: if user request is incorrect
// 1: if user requests "PUT" operation
// 2: if user requests "GET" operation
// Furthermore, if request is correct, its value (i.e. ID number and/or string) is saved to short unsigned and string values passed by pointers.
boost::regex exp("^[[:space:]]*(PUT|GET)[[:space:]]+([[:digit:]]{1,2})(?:[[:space:]]+(.*))?$");
boost::smatch what;
if (regex_match(user_request, what, exp, boost::match_extra))
{
short unsigned id_number = boost::lexical_cast<short unsigned>(what[2]);
if (what[1] == "PUT")
{
boost::regex exp1("^[a-zA-Z0-9]+$");
std::string value = boost::lexical_cast<std::string>(what[3]);
if (value.length() > 4095)
return 0;
if (!regex_match(value, exp1))
return 0;
else
{
*request_value = value;
*ID = id_number;
return 1;
}
}
if (what[1] == "GET")
{
*ID = id_number;
return 2;
}
}
if (!regex_match(user_request, what, exp, boost::match_extra))
return 0;
}
class Session
{
public:
void handleRequest(socket_ptr sock)
{
try
{
for (;;)
{
char data[max_length];
boost::system::error_code error;
size_t length = sock->read_some(boost::asio::buffer(data), error);
if (error == boost::asio::error::eof)
break; // Connection closed cleanly by peer.
else if (error)
throw boost::system::system_error(error); // Some other error.
// convert buffer data to string for further procession
std::string line(boost::asio::buffers_begin(boost::asio::buffer(data)), boost::asio::buffers_begin(boost::asio::buffer(data)) + length);
std::string reply; // will be "QK", "INVALID", or "OK <value>"
unsigned short vID;
unsigned short* ID = &vID;
std::string vrequest_value;
std::string* request_value = &vrequest_value;
unsigned short output = analyze_user_request(line, ID, request_value);
if (output == 1)
{
// PUT
reply = "OK";
user_array[*ID] = *request_value;
}
else if (output == 2)
{
// GET
reply = user_array[*ID];
if (reply == "")
reply = "EMPTY";
}
else
reply = "INVALID";
boost::system::error_code ignored_error;
size_t ans_len=reply.length();
boost::asio::write(*sock, boost::asio::buffer(reply));
}
}
catch (std::exception& e)
{
std::cerr << "Exception in thread: " << e.what() << "\n";
}
}
private:
std::string user_array[100];
};
typedef boost::shared_ptr<Session> SessionPtr;
void server(boost::asio::io_service& io_service, short port)
{
tcp::acceptor a(io_service, tcp::endpoint(tcp::v4(), port));
for (;;)
{
socket_ptr sock(new tcp::socket(io_service));
a.accept(*sock);
SessionPtr newSession(new Session());
boost::thread acceptThread(boost::bind(&Session::handleRequest, newSession, sock));
}
}
int main(int argc, char* argv[])
{
try
{
if (argc != 2)
{
std::cerr << "Usage: blocking_tcp_echo_server <port>\n";
return 1;
}
boost::asio::io_service io_service;
using namespace std; // For atoi.
server(io_service, atoi(argv[1]));
}
catch (std::exception& e)
{
std::cerr << "Exception: " << e.what() << "\n";
}
return 0;
}