GLib와 GIO를 이용한 간단한 네트워크 서버와 클라이언트 예제

예전에 인터넷에서 우연히 발견한 GLib와 GIO를 이용한 간단한 네트워크 서버/클라이언트 예제이다. GLib의 이벤트 루프와 GIO의 네트워크 기능을 활용하여 서버를 개발하는 좋은 샘플이 될 것으로 기대한다.

서버 소스

#include <glib.h>
#include <gio/gio.h>

static GInetAddress*
get_localhost()
{
    /* No clean way to handle IPV6, short of guess/check */
    GInetAddress* addr = g_inet_address_new_any(G_SOCKET_FAMILY_IPV4);
    if (!addr) {
        addr = g_inet_address_new_any(G_SOCKET_FAMILY_IPV6);
    }
    return addr;
}

/* this function will get called everytime a client attempts to connect */
gboolean
incoming_callback(GSocketService *service,
                  GSocketConnection *connection,
                  GObject *source_object,
                  gpointer user_data)
{
    g_print("Received connection from client!\n");
    GInputStream *istream = g_io_stream_get_input_stream(G_IO_STREAM(connection));
    gchar message[1024];
    g_input_stream_read(istream,
                        message,
                        1024,
                        NULL,
                        NULL);
    g_print("Message was: \"%s\"\n", message);
    return FALSE;
}

int
main(int argc, char **argv)
{
    /* initialize glib */
    g_type_init();

    /* initialize the thread system */
    if (!g_thread_supported())
        g_thread_init(NULL);

    GError *error = NULL;

    /* create a new socketservice */
    GSocketService *service = g_threaded_socket_service_new(10);

    /* create a new address */
    GInetAddress *inet_addr = get_localhost();
    GSocketAddress *sock_addr = g_inet_socket_address_new(inet_addr,
                                                          1500); /* your port goes here */

    /* connect to the address */
    GSocketAddress* effective_addr;
    g_socket_listener_add_address(G_SOCKET_LISTENER(service),
                                  sock_addr,
                                  G_SOCKET_TYPE_STREAM,
                                  G_SOCKET_PROTOCOL_TCP,
                                  NULL,
                                  &amp;effective_addr,
                                  &amp;error);

    /* don't forget to check for errors */
    if (error != NULL) {
        g_error(error-&gt;message);
    }

    /* listen to the 'incoming' signal */
    g_signal_connect(service,
                     "incoming",
                     G_CALLBACK(incoming_callback),
                     NULL);

    /* start the socket service */
    g_socket_service_start(service);

    /* enter mainloop */
    g_print("Waiting for client!\n");
    GMainLoop *loop = g_main_loop_new(NULL, FALSE);
    g_main_loop_run(loop);
    g_main_loop_unref(loop);

    return 0;
}

클라이언트 소스

#include <glib.h>
#include <gio/gio.h>

int
main(int argc, char **argv)
{
    /* initialize glib */
    g_type_init();

    GError *error = NULL;

    /* create a new connection */
    GSocketConnection *connection = NULL;
    GSocketClient *client = g_socket_client_new();

    /* connect to the host */
    connection = g_socket_client_connect_to_host(client,
                                                 (gchar *)"localhost",
                                                 1500, /* your port goes here */
                                                 NULL,
                                                 &amp;error);

    /* don't forget to check for errors */
    if (error != NULL) {
        g_error(error-&gt;message);
    }
    else {
        g_print("Connection successful!\n");
    }

    /* use the connection */
    GInputStream *istream = g_io_stream_get_input_stream(G_IO_STREAM(connection));
    GOutputStream *ostream = g_io_stream_get_output_stream(G_IO_STREAM(connection));
    g_output_stream_write(ostream,
                          "Hello server!", /* your message goes here */
                          13,              /* length of your message */
                          NULL,
                          &amp;error);

    /* don't forget to check for errors */
    if (error != NULL) {
        g_error(error-&gt;message);
    }

    return 0;
}