我正在使用 hiredis C 库连接到 redis 服务器。我不知道如何在订阅新消息后等待新消息。
我的代码如下:
signal(SIGPIPE, SIG_IGN );
struct event_base *base = event_base_new();
redisAsyncContext *c = redisAsyncConnect("127.0.0.1", 6379);
if (c->err) {
/* Let *c leak for now... */
printf("Error: %s\n", c->errstr);
return 1;
}
redisLibeventAttach(c, base);
redisAsyncSetConnectCallback(c, connectCallback);
redisAsyncSetDisconnectCallback(c, disconnectCallback);
redisAsyncCommand(c, NULL, NULL, "SET key %b", argv[argc - 1],
strlen(argv[argc - 1]));
redisAsyncCommand(c, getCallback, (char*) "end-1", "GET key");
redisAsyncCommand(c, getCallback, (char*) "end-1", "SUBSCRIBE foo");
现在如何告诉 hiredis 在 channel 上等待消息?
最佳答案
您不必告诉 hiredis 您需要在 channel 上等待:事件循环只会在先前注册的 Redis 连接上等待。
这是一个完整的例子:
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <signal.h>
#include "hiredis.h"
#include "async.h"
#include "adapters/libevent.h"
void subCallback(redisAsyncContext *c, void *r, void *priv) {
redisReply *reply = r;
if (reply == NULL) return;
if ( reply->type == REDIS_REPLY_ARRAY && reply->elements == 3 ) {
if ( strcmp( reply->element[0]->str, "subscribe" ) != 0 ) {
printf( "Received[%s] channel %s: %s\n",
(char*)priv,
reply->element[1]->str,
reply->element[2]->str );
}
}
}
void connectCallback(const redisAsyncContext *c, int status) {
if (status != REDIS_OK) {
printf("Error: %s\n", c->errstr);
return;
}
printf("Connected...\n");
}
void disconnectCallback(const redisAsyncContext *c, int status) {
if (status != REDIS_OK) {
printf("Error: %s\n", c->errstr);
return;
}
printf("Disconnected...\n");
}
int main (int argc, char **argv) {
signal(SIGPIPE, SIG_IGN);
struct event_base *base = event_base_new();
redisAsyncContext *c = redisAsyncConnect("127.0.0.1", 6379);
if (c->err) {
/* Let *c leak for now... */
printf("Error: %s\n", c->errstr);
return 1;
}
redisLibeventAttach(c,base);
redisAsyncSetConnectCallback(c,connectCallback);
redisAsyncSetDisconnectCallback(c,disconnectCallback);
redisAsyncCommand(c, subCallback, (char*) "sub", "SUBSCRIBE foo");
event_base_dispatch(base);
return 0;
}
您可以通过使用以下命令发布内容来测试它:
redis-cli publish foo something
event_base_dispatch 函数是实际启动事件循环并使其等待 Redis 订阅的函数。
关于redis - Hiredis 等待消息,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/16213676/