Example mongoose tcp client

mongoose_tcp_client.c

#include "mongoose.h"

// Public TCP echo server, see https://tcpbin.com/
#define TCP_SERVER_URL "tcp://tcpbin.com:4242"

// Custom TCP protocol client connection
static struct mg_connection *s_client_conn = NULL;

static void tcp_ev_handler(struct mg_connection *c, int ev, void *ev_data) {
  if (ev == MG_EV_OPEN) {
    // Connection is created. Set hexdump flag for debugging
    c->is_hexdumping = 1;
  } else if (ev == MG_EV_READ) {
    // Process received TCP data
    MG_INFO(("Received: %.*s", c->recv.len, c->recv.buf));
    c->recv.len = 0;  // Discard received data
  } else if (ev == MG_EV_CLOSE) {
    s_client_conn = NULL;
  }
}

static void timer_fn(void *arg) {
  struct mg_mgr *mgr = (struct mg_mgr *) arg;
  if (s_client_conn == NULL) {
    // TCP client is not connected. Reconnect
    s_client_conn = mg_connect(mgr, TCP_SERVER_URL, tcp_ev_handler, NULL);
  } else {
    // TCP client is connected. Send some message to it
    mg_printf(s_client_conn, "Hi! Current time is %llu\n", mg_now());
  }
}

int main(void) {
  struct mg_mgr mgr;
  mg_mgr_init(&mgr);
  mg_timer_add(&mgr, 2500, MG_TIMER_REPEAT, timer_fn, &mgr);
  for (;;) {
    mg_mgr_poll(&mgr, 100);
  }
  mg_mgr_free(&mgr);
  return 0;
}