Titanic client example in C

//
// Titanic client example
// Implements client side of http://rfc.zeromq.org/spec:9

// Lets us build this source without creating a library
#include "mdcliapi.c"

// Calls a TSP service
// Returns reponse if successful (status code 200 OK), else NULL
//

static zmsg_t *
s_service_call (mdcli_t *session, char *service, zmsg_t **request_p)
{
zmsg_t *reply = mdcli_send (session, service, request_p);
if (reply) {
zframe_t *status = zmsg_pop (reply);
if (zframe_streq (status, "200")) {
zframe_destroy (&status);
return reply;
}
else
if (zframe_streq (status, "400")) {
printf ("E: client fatal error, aborting\n");
exit (EXIT_FAILURE);
}
else
if (zframe_streq (status, "500")) {
printf ("E: server fatal error, aborting\n");
exit (EXIT_FAILURE);
}
}
else
exit (EXIT_SUCCESS); // Interrupted or failed

zmsg_destroy (&reply);
return NULL; // Didn't succeed, don't care why not
}

int main (int argc, char *argv [])
{
int verbose = (argc > 1 && streq (argv [1], "-v"));
mdcli_t *session = mdcli_new ("tcp://localhost:5555", verbose);

// 1. Send 'echo' request to Titanic
zmsg_t *request = zmsg_new ();
zmsg_addstr (request, "echo");
zmsg_addstr (request, "Hello world");
zmsg_t *reply = s_service_call (
session, "titanic.request", &request);

zframe_t *uuid = NULL;
if (reply) {
uuid = zmsg_pop (reply);
zmsg_destroy (&reply);
zframe_print (uuid, "I: request UUID ");
}

// 2. Wait until we get a reply
while (!zctx_interrupted) {
zclock_sleep (100);
request = zmsg_new ();
zmsg_add (request, zframe_dup (uuid));
zmsg_t *reply = s_service_call (
session, "titanic.reply", &request);

if (reply) {
char *reply_string = zframe_strdup (zmsg_last (reply));
printf ("Reply: %s\n", reply_string);
free (reply_string);
zmsg_destroy (&reply);

// 3. Close request
request = zmsg_new ();
zmsg_add (request, zframe_dup (uuid));
reply = s_service_call (session, "titanic.close", &request);
zmsg_destroy (&reply);
break;
}
else {
printf ("I: no reply yet, trying again…\n");
zclock_sleep (5000); // Try again in 5 seconds
}
}
zframe_destroy (&uuid);
mdcli_destroy (&session);
return 0;
}