tcp_client-windows.h
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// Copyright(c) 2015-present, Gabi Melman & spdlog contributors.
// Distributed under the MIT License (http://opensource.org/licenses/MIT)
#pragma once
#define WIN32_LEAN_AND_MEAN
// tcp client helper
#include <spdlog/common.h>
#include <spdlog/details/os.h>
#include <winsock2.h>
#include <windows.h>
#include <ws2tcpip.h>
#include <stdlib.h>
#include <stdio.h>
#include <string>
#pragma comment(lib, "Ws2_32.lib")
#pragma comment(lib, "Mswsock.lib")
#pragma comment(lib, "AdvApi32.lib")
namespace spdlog {
namespace details {
class tcp_client
{
SOCKET socket_ = INVALID_SOCKET;
static bool winsock_initialized_()
{
SOCKET s = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
if (s == INVALID_SOCKET)
{
return false;
}
else
{
closesocket(s);
return true;
}
}
static void init_winsock_()
{
WSADATA wsaData;
auto rv = WSAStartup(MAKEWORD(2, 2), &wsaData);
if (rv != 0)
{
throw_winsock_error_("WSAStartup failed", ::WSAGetLastError());
}
}
static void throw_winsock_error_(const std::string &msg, int last_error)
{
char buf[512];
::FormatMessage(FORMAT_MESSAGE_FROM_SYSTEM | FORMAT_MESSAGE_IGNORE_INSERTS, NULL, last_error,
MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT), buf, (sizeof(buf) / sizeof(char)), NULL);
throw_spdlog_ex(fmt::format("tcp_sink - {}: {}", msg, buf));
}
public:
bool is_connected() const
{
return socket_ != INVALID_SOCKET;
}
void close()
{
::closesocket(socket_);
socket_ = INVALID_SOCKET;
WSACleanup();
}
SOCKET fd() const
{
return socket_;
}
~tcp_client()
{
close();
}
// try to connect or throw on failure
void connect(const std::string &host, int port)
{
// initialize winsock if needed
if (!winsock_initialized_())
{
init_winsock_();
}
if (is_connected())
{
close();
}
struct addrinfo hints
{};
ZeroMemory(&hints, sizeof(hints));
hints.ai_family = AF_INET; // IPv4
hints.ai_socktype = SOCK_STREAM; // TCP
hints.ai_flags = AI_NUMERICSERV; // port passed as as numeric value
hints.ai_protocol = 0;
auto port_str = std::to_string(port);
struct addrinfo *addrinfo_result;
auto rv = ::getaddrinfo(host.c_str(), port_str.c_str(), &hints, &addrinfo_result);
int last_error = 0;
if (rv != 0)
{
last_error = ::WSAGetLastError();
WSACleanup();
throw_winsock_error_("getaddrinfo failed", last_error);
}
// Try each address until we successfully connect(2).
for (auto *rp = addrinfo_result; rp != nullptr; rp = rp->ai_next)
{
socket_ = socket(rp->ai_family, rp->ai_socktype, rp->ai_protocol);
if (socket_ == INVALID_SOCKET)
{
last_error = ::WSAGetLastError();
WSACleanup();
continue;
}
if (::connect(socket_, rp->ai_addr, (int)rp->ai_addrlen) == 0)
{
break;
}
else
{
last_error = ::WSAGetLastError();
close();
}
}
::freeaddrinfo(addrinfo_result);
if (socket_ == INVALID_SOCKET)
{
WSACleanup();
throw_winsock_error_("connect failed", last_error);
}
// set TCP_NODELAY
int enable_flag = 1;
::setsockopt(socket_, IPPROTO_TCP, TCP_NODELAY, (char *)&enable_flag, sizeof(enable_flag));
}
// Send exactly n_bytes of the given data.
// On error close the connection and throw.
void send(const char *data, size_t n_bytes)
{
size_t bytes_sent = 0;
while (bytes_sent < n_bytes)
{
const int send_flags = 0;
auto write_result = ::send(socket_, data + bytes_sent, (int)(n_bytes - bytes_sent), send_flags);
if (write_result == SOCKET_ERROR)
{
int last_error = ::WSAGetLastError();
close();
throw_winsock_error_("send failed", last_error);
}
if (write_result == 0) // (probably should not happen but in any case..)
{
break;
}
bytes_sent += static_cast<size_t>(write_result);
}
}
};
} // namespace details
} // namespace spdlog