2e7d7cbabd
Proper support for RESP3 PUSH messages. By default, PUSH messages are now intercepted and the reply memory freed. This means existing code should work unchanged when connecting to Redis >= 6.0.0 even if `CLIENT TRACKING` were then enabled. Additionally, we define two callbacks users can configure if they wish to handle these messages in a custom way: void redisPushFn(void *privdata, void *reply); void redisAsyncPushFn(redisAsyncContext *ac, void *reply); See #825
119 lines
3.8 KiB
C
119 lines
3.8 KiB
C
#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <hiredis.h>
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#include <win32.h>
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#define KEY_COUNT 5
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#define panicAbort(fmt, ...) \
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do { \
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fprintf(stderr, "%s:%d:%s(): " fmt, __FILE__, __LINE__, __func__, __VA_ARGS__); \
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exit(-1); \
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} while (0)
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static void assertReplyAndFree(redisContext *context, redisReply *reply, int type) {
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if (reply == NULL)
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panicAbort("NULL reply from server (error: %s)", context->errstr);
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if (reply->type != type) {
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if (reply->type == REDIS_REPLY_ERROR)
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fprintf(stderr, "Redis Error: %s\n", reply->str);
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panicAbort("Expected reply type %d but got type %d", type, reply->type);
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}
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freeReplyObject(reply);
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}
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/* Switch to the RESP3 protocol and enable client tracking */
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static void enableClientTracking(redisContext *c) {
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redisReply *reply = redisCommand(c, "HELLO 3");
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if (reply == NULL || c->err) {
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panicAbort("NULL reply or server error (error: %s)", c->errstr);
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}
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if (reply->type != REDIS_REPLY_MAP) {
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fprintf(stderr, "Error: Can't send HELLO 3 command. Are you sure you're ");
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fprintf(stderr, "connected to redis-server >= 6.0.0?\nRedis error: %s\n",
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reply->type == REDIS_REPLY_ERROR ? reply->str : "(unknown)");
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exit(-1);
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}
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freeReplyObject(reply);
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/* Enable client tracking */
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reply = redisCommand(c, "CLIENT TRACKING ON");
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assertReplyAndFree(c, reply, REDIS_REPLY_STATUS);
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}
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void pushReplyHandler(void *privdata, void *r) {
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redisReply *reply = r;
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int *invalidations = privdata;
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/* Sanity check on the invalidation reply */
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if (reply->type != REDIS_REPLY_PUSH || reply->elements != 2 ||
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reply->element[1]->type != REDIS_REPLY_ARRAY ||
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reply->element[1]->element[0]->type != REDIS_REPLY_STRING)
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{
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panicAbort("%s", "Can't parse PUSH message!");
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}
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/* Increment our invalidation count */
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*invalidations += 1;
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printf("pushReplyHandler(): INVALIDATE '%s' (invalidation count: %d)\n",
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reply->element[1]->element[0]->str, *invalidations);
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freeReplyObject(reply);
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}
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int main(int argc, char **argv) {
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unsigned int j, invalidations = 0;
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redisContext *c;
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redisReply *reply;
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const char *hostname = (argc > 1) ? argv[1] : "127.0.0.1";
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int port = (argc > 2) ? atoi(argv[2]) : 6379;
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redisOptions o = {0};
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REDIS_OPTIONS_SET_TCP(&o, hostname, port);
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/* Set our custom PUSH message handler */
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o.push_cb = pushReplyHandler;
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c = redisConnectWithOptions(&o);
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if (c == NULL || c->err)
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panicAbort("Connection error: %s", c ? c->errstr : "OOM");
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/* Enable RESP3 and turn on client tracking */
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enableClientTracking(c);
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/* Set our context privdata to the address of our invalidation counter. Each
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* time our PUSH handler is called, hiredis will pass the privdata for context */
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c->privdata = &invalidations;
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/* Set some keys and then read them back. Once we do that, Redis will deliver
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* invalidation push messages whenever the key is modified */
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for (j = 0; j < KEY_COUNT; j++) {
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reply = redisCommand(c, "SET key:%d initial:%d", j, j);
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assertReplyAndFree(c, reply, REDIS_REPLY_STATUS);
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reply = redisCommand(c, "GET key:%d", j);
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assertReplyAndFree(c, reply, REDIS_REPLY_STRING);
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}
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/* Trigger invalidation messages by updating keys we just read */
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for (j = 0; j < KEY_COUNT; j++) {
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printf(" main(): SET key:%d update:%d\n", j, j);
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reply = redisCommand(c, "SET key:%d update:%d", j, j);
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assertReplyAndFree(c, reply, REDIS_REPLY_STATUS);
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printf(" main(): SET REPLY OK\n");
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}
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printf("\nTotal detected invalidations: %d, expected: %d\n", invalidations, KEY_COUNT);
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/* PING server */
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redisFree(c);
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}
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