我正在尝试在 Redis 中使用 pub-sub。我要做的是打开两个redis-cli
. 第一个我发出命令flushall
以确保以绿色启动。
然后在另一个终端中,我打开MONITOR以打印来自 Golang 示例客户端的所有命令(代码如下)。
这是我从 MONITOR 打印的内容:
1590207069.340860 [0 127.0.0.1:58910] "smembers" "user:Ali:rooms"
1590207069.341380 [0 127.0.0.1:58910] "sadd" "user:Ali:rooms" "New"
1590207069.345266 [0 127.0.0.1:58910] "smembers" "user:Ali:rooms"
1590207069.353706 [0 127.0.0.1:58910] "sadd" "user:Ali:rooms" "Old"
1590207069.354219 [0 127.0.0.1:58912] "subscribe" "New"
1590207069.354741 [0 127.0.0.1:58910] "smembers" "user:Ali:rooms"
1590207069.355444 [0 127.0.0.1:58912] "unsubscribe" "New" "Old"
1590207069.356754 [0 127.0.0.1:58910] "sadd" "user:Ali:rooms" "OldPlusPlus"
1590207069.357206 [0 127.0.0.1:58914] "subscribe" "New" "Old"
1590207069.357656 [0 127.0.0.1:58910] "smembers" "user:Ali:rooms"
1590207069.358362 [0 127.0.0.1:58912] "unsubscribe" "OldPlusPlus" "New" "Old"
1590207069.361030 [0 127.0.0.1:58916] "subscribe" "OldPlusPlus" "New" "Old"
我试图让客户端对随着时间的推移打开的所有通道都有一个连接。而不是一个连接/线程来处理 Redis 的每个通道。因此,每当需要新的订阅请求时,我都会尝试从客户端删除所有以前的订阅,并对旧频道和新频道进行新订阅。
但似乎该unsubscribe
命令没有按预期工作(或者我遗漏了一些东西)!
因为当我尝试获取每个频道的客户端数量时,从第一个终端:
127.0.0.1:6379> pubsub numsub OldPlusPlus New Old
1) "OldPlusPlus"
2) (integer) 1
3) "New"
4) (integer) 2
5) "Old"
6) (integer) 2
除了当我尝试向“新”频道发送消息时,我的 go 客户端收到了两次消息!
这是生成上述命令的代码:
package main
import (
"fmt"
"github.com/go-redis/redis/v7"
"log"
)
type user struct {
name string
rooms []string
endSub chan bool
sub bool
}
func (u *user) connect(rdb *redis.Client) error {
// get all user rooms (from DB) and start subscribe
r, err := rdb.SMembers(fmt.Sprintf("user:%s:rooms", u.name)).Result()
if err != nil {
return err
}
u.rooms = r
if len(u.rooms) == 0 {
return nil
}
u.doSubscribe(rdb)
return nil
}
func (u *user) subscribe(room string, rdb *redis.Client) error {
// check if already subscribed
for i := range u.rooms {
if u.rooms[i] == room {
return nil
}
}
// add room to user
userRooms := fmt.Sprintf("user:%s:rooms", u.name)
if err := rdb.SAdd(userRooms, room).Err(); err != nil {
return err
}
// get all user rooms (from DB) and start subscribe
r, err := rdb.SMembers(userRooms).Result()
if err != nil {
return err
}
u.rooms = r
if u.sub {
u.endSub <- true
}
u.doSubscribe(rdb)
return nil
}
func (u *user) doSubscribe(rdb *redis.Client) {
sub := rdb.Subscribe(u.rooms...)
go func() {
u.sub = true
fmt.Println("starting the listener for user:", u.name, "on rooms:", u.rooms)
for {
select {
case msg, ok := <-sub.Channel():
if !ok {
break
}
fmt.Println(msg.Payload)
case <-u.endSub:
fmt.Println("Stop listening for user:", u.name, "from rooms:", u.rooms)
if err := sub.Unsubscribe(u.rooms...); err != nil {
fmt.Println("error unsubscribing")
return
}
break
}
}
}()
}
func (u *user) unsubscribe(room string, rdb *redis.Client) error {
return nil
}
var rdb *redis.Client
func main() {
rdb = redis.NewClient(&redis.Options{Addr: "localhost:6379"})
u := &user{
name: "Ali",
endSub: make(chan bool),
}
if err := u.connect(rdb); err != nil {
log.Fatal(err)
}
if err := u.subscribe("New", rdb); err != nil {
log.Fatal(err)
}
if err := u.subscribe("Old", rdb); err != nil {
log.Fatal(err)
}
if err := u.subscribe("OldPlusPlus", rdb); err != nil {
log.Fatal(err)
}
select {}
}