cpprestsdk handler class crashes when using STL container as member - c++

Question

I wrote a simple code using cpprestsdk. I use a map (records) as a member of CommandHandler class, and manipulate it in a public method (has_record()).
it works before handler.open().wait() runs, but when I call it in a request, it crashes!
Here is my code:
#define BOOST_DATE_TIME_NO_LIB
#include <string>
#include <vector>
#include <cpprest/uri.h>
#include <cpprest/http_listener.h>
#include <cpprest/asyncrt_utils.h>
using namespace std;
using namespace web;
using namespace http;
using namespace utility;
using namespace http::experimental::listener;
class CommandHandler
{
public:
CommandHandler(utility::string_t url);
pplx::task<void> open() { return m_listener.open(); }
pplx::task<void> close() { return m_listener.close(); }
bool has_record();
private:
std::map< std::string, unsigned int > records;
void handle_get_or_post(http_request message);
http_listener m_listener;
};
bool CommandHandler::has_record()
{
return records.size() > 0 && records.find("1") != records.end();
}
CommandHandler::CommandHandler(utility::string_t url) : m_listener(url)
{
m_listener.support(methods::GET, std::bind(&CommandHandler::handle_get_or_post, this, std::placeholders::_1));
m_listener.support(methods::POST, std::bind(&CommandHandler::handle_get_or_post, this, std::placeholders::_1));
}
void CommandHandler::handle_get_or_post(http_request request)
{
if(this->has_record())
request.reply(status_codes::OK, 1);
else
request.reply(status_codes::OK, 0);
};
int main(int argc, char** argv)
{
try
{
utility::string_t address = U("http://127.0.0.1:9595");
uri_builder uri(address);
auto addr = uri.to_uri().to_string();
CommandHandler handler(addr);
if(handler.has_record())
std::cout<<"work!";
handler.open().wait();
ucout << utility::string_t(U("Listening for requests at: ")) << addr << std::endl;
ucout << U("Press ENTER key to quit...") << std::endl;
std::string line;
std::getline(std::cin, line);
handler.close().wait();
}
catch (std::exception& ex)
{
ucout << U("Exception: ") << ex.what() << std::endl;
ucout << U("Press ENTER key to quit...") << std::endl;
std::string line;
std::getline(std::cin, line);
}
return 0;
}

Answer 1

I found the problem but I don't understand why it throws. The problem is in this line of code:
request.reply(status_codes::OK, 0);
That 0 throws an exception