Redis 发布与订阅

Redis 提供的发布与订阅命令

命令	用例和描述
SUBSCRIBE	SUBSCRIBE channel [channel ...] —— 订阅给定的一个或多个频道
UNSUBSCRIBE	UNSUBSCRIBE [channel [channel ...]] —— 退订给定的频道，如果没有给定则退订所有
PUBLISH	PUBLISH channel message —— 向给定的频道发送消息
PSUBSCRIBE	PSUBSCRIBE pattern [pattern ...] —— 订阅与给定模式相匹配的所有频道
PUNSUBSCRIBE	PUNSUBSCRIBE [pattern [pattern ...]] —— 退订给定的模式，如果没有指定则退订所有

Python 示例 :

import time
import threading
import redis
​
conn = redis.Redis()
​
def publisher(n):
    time.sleep(1)
    for i in range(n):
        # 将消息发布到频道
        conn.publish('channel', i)
        time.sleep(1)
​
def run_pubsub():
    threading.Thread(target=publisher, args=(3,)).start()
    pubsub = conn.pubsub()
    # 订阅频道
    pubsub.subscribe(['channel'])
    count = 0
    # 监听并打印消息
    for item in pubsub.listen():
        print(item)
        count += 1
        if count == 4:
            pubsub.unsubscribe()
        if count == 5:
            break
​
​
run_pubsub()

输出结果 :

{'channel': b'channel', 'data': 1, 'type': 'subscribe', 'pattern': None}
{'channel': b'channel', 'data': b'0', 'type': 'message', 'pattern': None}
{'channel': b'channel', 'data': b'1', 'type': 'message', 'pattern': None}
{'channel': b'channel', 'data': b'2', 'type': 'message', 'pattern': None}
{'channel': b'channel', 'data': 0, 'type': 'unsubscribe', 'pattern': None}