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/*
* Copyright (c) 2020, Michael Grunder <michael dot grunder at gmail dot com>
*
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* * Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* * Neither the name of Redis nor the names of its contributors may be used
* to endorse or promote products derived from this software without
* specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <hiredis.h>
#include <win32.h>
#define KEY_COUNT 5
#define panicAbort(fmt, ...) \
do { \
fprintf(stderr, "%s:%d:%s(): " fmt, __FILE__, __LINE__, __func__, __VA_ARGS__); \
exit(-1); \
} while (0)
static void assertReplyAndFree(redisContext *context, redisReply *reply, int type) {
if (reply == NULL)
panicAbort("NULL reply from server (error: %s)", context->errstr);
if (reply->type != type) {
if (reply->type == REDIS_REPLY_ERROR)
fprintf(stderr, "Redis Error: %s\n", reply->str);
panicAbort("Expected reply type %d but got type %d", type, reply->type);
}
freeReplyObject(reply);
}
/* Switch to the RESP3 protocol and enable client tracking */
static void enableClientTracking(redisContext *c) {
redisReply *reply = redisCommand(c, "HELLO 3");
if (reply == NULL || c->err) {
panicAbort("NULL reply or server error (error: %s)", c->errstr);
}
if (reply->type != REDIS_REPLY_MAP) {
fprintf(stderr, "Error: Can't send HELLO 3 command. Are you sure you're ");
fprintf(stderr, "connected to redis-server >= 6.0.0?\nRedis error: %s\n",
reply->type == REDIS_REPLY_ERROR ? reply->str : "(unknown)");
exit(-1);
}
freeReplyObject(reply);
/* Enable client tracking */
reply = redisCommand(c, "CLIENT TRACKING ON");
assertReplyAndFree(c, reply, REDIS_REPLY_STATUS);
}
void pushReplyHandler(void *privdata, void *r) {
redisReply *reply = r;
int *invalidations = privdata;
/* Sanity check on the invalidation reply */
if (reply->type != REDIS_REPLY_PUSH || reply->elements != 2 ||
reply->element[1]->type != REDIS_REPLY_ARRAY ||
reply->element[1]->element[0]->type != REDIS_REPLY_STRING)
{
panicAbort("%s", "Can't parse PUSH message!");
}
/* Increment our invalidation count */
*invalidations += 1;
printf("pushReplyHandler(): INVALIDATE '%s' (invalidation count: %d)\n",
reply->element[1]->element[0]->str, *invalidations);
freeReplyObject(reply);
}
/* We aren't actually freeing anything here, but it is included to show that we can
* have hiredis call our data destructor when freeing the context */
void privdata_dtor(void *privdata) {
unsigned int *icount = privdata;
printf("privdata_dtor(): In context privdata dtor (invalidations: %u)\n", *icount);
}
int main(int argc, char **argv) {
unsigned int j, invalidations = 0;
redisContext *c;
redisReply *reply;
const char *hostname = (argc > 1) ? argv[1] : "127.0.0.1";
int port = (argc > 2) ? atoi(argv[2]) : 6379;
redisOptions o = {0};
REDIS_OPTIONS_SET_TCP(&o, hostname, port);
/* Set our context privdata to the address of our invalidation counter. Each
* time our PUSH handler is called, hiredis will pass the privdata for context.
*
* This could also be done after we create the context like so:
*
* c->privdata = &invalidations;
* c->free_privdata = privdata_dtor;
*/
REDIS_OPTIONS_SET_PRIVDATA(&o, &invalidations, privdata_dtor);
/* Set our custom PUSH message handler */
o.push_cb = pushReplyHandler;
c = redisConnectWithOptions(&o);
if (c == NULL || c->err)
panicAbort("Connection error: %s", c ? c->errstr : "OOM");
/* Enable RESP3 and turn on client tracking */
enableClientTracking(c);
/* Set some keys and then read them back. Once we do that, Redis will deliver
* invalidation push messages whenever the key is modified */
for (j = 0; j < KEY_COUNT; j++) {
reply = redisCommand(c, "SET key:%d initial:%d", j, j);
assertReplyAndFree(c, reply, REDIS_REPLY_STATUS);
reply = redisCommand(c, "GET key:%d", j);
assertReplyAndFree(c, reply, REDIS_REPLY_STRING);
}
/* Trigger invalidation messages by updating keys we just read */
for (j = 0; j < KEY_COUNT; j++) {
printf(" main(): SET key:%d update:%d\n", j, j);
reply = redisCommand(c, "SET key:%d update:%d", j, j);
assertReplyAndFree(c, reply, REDIS_REPLY_STATUS);
printf(" main(): SET REPLY OK\n");
}
printf("\nTotal detected invalidations: %d, expected: %d\n", invalidations, KEY_COUNT);
/* PING server */
redisFree(c);
}
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