Tcp Sockets

Using TCP sockets for communication between a server and a client.

This example demonstrates how to set up a TCP server and client, exchanging data, using the Cubos engine.

The TCP sockets are wrapped around a cubos::core::net::TcpListener and cubos::core::net::TcpStream classes for a better API and simpler usage.

First, we need the network dependencies:

#include <cubos/core/net/tcp_listener.hpp>
#include <cubos/core/net/tcp_stream.hpp>

We'll also define some dummy constants for demonstration purposes:

#define SERVER_ADDRESS Address::LocalHost
#define SERVER_PORT 8080

Now, let's launch the "TCP server", which will be a cubos::core::net::TcpListener waiting for a new connection, and quit after receveing a message from client via cubos::core::net::TcpStream .

void runServer()
{
    TcpListener listener;
    listener.listen(SERVER_ADDRESS, SERVER_PORT, 1);

    CUBOS_DEBUG("Server is listening");

    TcpStream clientStream;
    while (listener.accept(clientStream))
    {
        char buffer[1024];
        if (std::size_t bytesRead = clientStream.read(buffer, sizeof(buffer)); bytesRead > 0)
        {
            CUBOS_INFO("Received message: {} with size {}", buffer, bytesRead);
            break;
        }
    }

    listener.close();
}

Server is up and waiting, so let's create the client which will send a message to the server.

void runClient()
{
    TcpStream stream;
    stream.connect(SERVER_ADDRESS, SERVER_PORT);

    const char* message = "Hello Cubos!";
    stream.write(message, std::strlen(message));
    stream.disconnect();
}

To finish off, let's launch them in separate threads, because we are using blocking methods (such as accept).

Output:

[20:36:53.918] [tcp_listener.cpp:67 listen] info: TCP listener socket '3' at address "127.0.0.1" with port '8080'
[20:36:53.919] [main.cpp:28 runServer] debug: Server is listening
[20:36:54.918] [tcp_listener.cpp:80 accept] info: Connecting stream to socket
[20:36:54.919] [tcp_stream.cpp:45 connect] info: New TCP stream at address "127.0.0.1" and port '8080'
[20:36:54.919] [tcp_stream.cpp:54 inner] info: New TCP stream at socket 4
[20:36:54.919] [tcp_stream.cpp:136 write] info: Sent TCP message
[20:36:54.919] [tcp_stream.cpp:111 read] info: Incoming TCP message
[20:36:54.920] [main.cpp:36 runServer] info: Received message: "Hello Cubos!" with size 12
[20:36:54.920] [tcp_stream.cpp:62 disconnect] warn: Closing TCP stream socket: '5'
[20:36:54.920] [tcp_listener.cpp:89 close] warn: Closing TCP listener socket: '3'
[20:36:54.921] [tcp_stream.cpp:62 disconnect] warn: Closing TCP stream socket: '4'