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| /* client.c - see http://ultramessaging.github.io/UMExamples/client/c/index.html
*
* Copyright (c) 2005-2017 Informatica Corporation. All Rights Reserved.
* Permission is granted to licensees to use
* or alter this software for any purpose, including commercial applications,
* according to the terms laid out in the Software License Agreement.
*
* This source code example is provided by Informatica for educational
* and evaluation purposes only.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND INFORMATICA DISCLAIMS ALL WARRANTIES
* EXPRESS OR IMPLIED, INCLUDING WITHOUT LIMITATION, ANY IMPLIED WARRANTIES OF
* NON-INFRINGEMENT, MERCHANTABILITY OR FITNESS FOR A PARTICULAR
* PURPOSE. INFORMATICA DOES NOT WARRANT THAT USE OF THE SOFTWARE WILL BE
* UNINTERRUPTED OR ERROR-FREE. INFORMATICA SHALL NOT, UNDER ANY CIRCUMSTANCES, BE
* LIABLE TO LICENSEE FOR LOST PROFITS, CONSEQUENTIAL, INCIDENTAL, SPECIAL OR
* INDIRECT DAMAGES ARISING OUT OF OR RELATED TO THIS AGREEMENT OR THE
* TRANSACTIONS CONTEMPLATED HEREUNDER, EVEN IF INFORMATICA HAS BEEN APPRISED OF
* THE LIKELIHOOD OF SUCH DAMAGES.
*/
#include <stdio.h>
#include <string.h>
#if defined(_MSC_VER)
/* Windows-only includes */
#include <winsock2.h>
#define MSLEEP(s) Sleep(s) /* Portable millisecond sleep. */
#else
/* Unix-only includes */
#include <stdlib.h>
#include <unistd.h>
#define MSLEEP(s) usleep((s) * 1000) /* Portable millisecond sleep. */
#endif
#include <lbm/lbm.h>
typedef struct server_s {
lbm_context_t *ctx;
char *topic_name; /* Topic the server is subscribed to. */
lbm_src_t *src; /* Source to send requests to server. */
lbm_rcv_t *rcv; /* Receiver for responses from server. */
int state; /* 0=Waiting for registration, 1=registered. */
} server_t;
/* Header for request messages. */
typedef struct req_hdr_s {
char data[8];
} req_hdr_t;
/* Example error checking macro. Include after each UM call. */
#define EX_LBM_CHK(err) do { \
if ((err) < 0) { \
fprintf(stderr, "%s:%d, lbm error: '%s'\n", \
__FILE__, __LINE__, lbm_errmsg()); \
exit(1); \
} \
} while (0)
int response_rcv_cb(lbm_rcv_t *rcv, lbm_msg_t *msg, void *clientd)
{
server_t *server = (server_t *)clientd;
req_hdr_t *req_hdr;
const char *req_data;
switch (msg->type)
{
case LBM_MSG_DATA: /* Received a message from the client. */
printf("Received %ld bytes on topic %s: '%.*s'\n",
(long)msg->len, msg->topic_name, (int)msg->len, msg->data);
if (msg->len > 1 && msg->data[0] == 'r') {
/* Should check for success. */
server->state = 1; /* Registered. */
}
else if (msg->len > sizeof(req_hdr_t) && msg->data[0] == 'R') {
req_hdr = (req_hdr_t *)msg->data;
req_data = &msg->data[sizeof(req_hdr_t)];
/* Process response message. */
}
break;
case LBM_MSG_BOS:
printf("[%s][%s], BOS\n", msg->topic_name, msg->source);
break;
case LBM_MSG_EOS:
printf("[%s][%s], EOS\n", msg->topic_name, msg->source);
break;
default: /* unexpected receiver event */
printf("Receive event type %d topic='%s', source='%s'\n",
msg->type, msg->topic_name, msg->source);
break;
} /* switch msg->type */
return 0;
} /* response_rcv_cb */
int main(int argc, char **argv)
{
lbm_context_t *ctx;
server_t server; /* State information for the server. */
char response_topic_name[256];
int err;
/* Get (pretty much) unique client name. */
sprintf(response_topic_name, "Client.%lx.Response", (long)getpid());
#if defined(_MSC_VER)
/* windows-specific code */
WSADATA wsadata;
int wsStat = WSAStartup(MAKEWORD(2,2), &wsadata);
if (wsStat != 0) {
printf("line %d: wsStat=%d\n",__LINE__,wsStat); exit(1);
}
#endif
server.ctx = NULL;
server.topic_name = "Server1.Request";
server.src = NULL; /* Source to send requests to server. */
server.rcv = NULL; /* Receiver for responses from server. */
server.state = 0; /* Waiting for registration. */
err = lbm_config("client.cfg");
EX_LBM_CHK(err);
err = lbm_context_create(&ctx, NULL, NULL, NULL);
EX_LBM_CHK(err);
server.ctx = ctx;
/* Create source to send requests to server. */
{
lbm_topic_t *topic;
err = lbm_src_topic_alloc(&topic, ctx, server.topic_name, NULL);
EX_LBM_CHK(err);
err = lbm_src_create(&server.src, ctx, topic, NULL, NULL, NULL);
EX_LBM_CHK(err);
}
/* Create receiver for responses from server. */
{
lbm_topic_t *topic;
err = lbm_rcv_topic_lookup(&topic, ctx, response_topic_name, NULL);
EX_LBM_CHK(err);
err = lbm_rcv_create(&server.rcv, ctx, topic, response_rcv_cb, &server, NULL);
EX_LBM_CHK(err);
}
/* Register with the server. May need multiple tries. */
{
int try_cnt = 0;
int backoff_delay;
char register_msg[257];
sprintf(register_msg, "r%s", response_topic_name);
backoff_delay = 1; /* In milliseconds. */
MSLEEP(backoff_delay); /* Let TR complete. */
while (server.state == 0) {
try_cnt ++;
err = lbm_src_send(server.src, register_msg,
strlen(register_msg) + 1, LBM_MSG_FLUSH | LBM_SRC_BLOCK);
EX_LBM_CHK(err);
printf("Sent '%s' to %s\n", register_msg, server.topic_name);
/* Exponential backoff, to max of 1 sec. */
backoff_delay *= 2; /* Exponential backoff to max of 1 sec. */
if (backoff_delay > 1000) {
backoff_delay = 1000;
}
MSLEEP(backoff_delay); /* Wait for server response. */
}
printf("Took %d tries to register with server.\n", try_cnt);
}
/* Main work of the program, which includes sending 5 requests. */
{
int i;
char send_buf[500];
req_hdr_t *req_hdr = (req_hdr_t *)send_buf;
memset((char *)req_hdr, '0', sizeof(req_hdr_t));
req_hdr->data[0] = 'R';
for (i = 0; i < 5; i++) {
/* The application builds a request into <tt>request_msg</tt>. */
char request_msg[257];
sprintf(request_msg, "%s.%d", response_topic_name, i);
/* The application message is copied in after the header. */
strcpy(&send_buf[sizeof(req_hdr_t)], request_msg);
err = lbm_src_send(server.src, send_buf, strlen(send_buf) + 1,
LBM_MSG_FLUSH | LBM_SRC_NONBLOCK);
EX_LBM_CHK(err);
MSLEEP(1000);
}
}
printf("Client exiting.\n");
err = lbm_rcv_delete(server.rcv);
EX_LBM_CHK(err);
err = lbm_src_delete(server.src);
EX_LBM_CHK(err);
err = lbm_context_delete(ctx);
EX_LBM_CHK(err);
#if defined(_MSC_VER)
WSACleanup();
#endif
return 0;
} /* main */
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