The PUBSUB command is an introspection command that allows to inspect the state of the Pub/Sub subsystem. It is composed of subcommands that are documented separately. The general form is: PUBSUB 是自省命令,能够检测PUB/SUB子系统的状态。它由分别详细描述的子命令组成。通用格式如下: PUBSUB ... args ...

PUBSUB CHANNELS [pattern]

Lists the currently active channels. An active channel is a Pub/Sub channel with one or more subscribers (not including clients subscribed to patterns). 列出当前active channels.活跃是指信道含有一个或多个订阅者(不包括从模式接收订阅的客户端) If no pattern is specified, all the channels are listed, otherwise if pattern is specified only channels matching the specified glob-style pattern are listed. 如果pattern未提供,所有的信道都被列出,否则只列出匹配上指定全局-类型模式的信道被列出.

@return

@array-reply: a list of active channels, optionally matching the specified pattern. @array-reply: 活跃的信道列表,或者符合指定模式的信道

PUBSUB NUMSUB [channel-1 ... channel-N]

Returns the number of subscribers (not counting clients subscribed to patterns) for the specified channels. 列出指定信道的订阅者个数(不包括订阅模式的客户端订阅者) @return

@array-reply: a list of channels and number of subscribers for every channel. The format is channel, count, channel, count, …, so the list is flat. The order in which the channels are listed is the same as the order of the channels specified in the command call. @array-reply: 信道的列表和每个列表中订阅者的个数. 格式为 信道,个数,信道,个数,… 简单的列表.

Note that it is valid to call this command without channels. In this case it will just return an empty list. 注意,不给定任何频道而直接调用这个命令也是可以的, 在这种情况下,命令只返回一个空列表.

PUBSUB NUMPAT

Returns the number of subscriptions to patterns (that are performed using the PSUBSCRIBE command). Note that this is not just the count of clients subscribed to patterns but the total number of patterns all the clients are subscribed to. 返回订阅模式的数量(使用命令PSUBSCRIBE实现).注意, 这个命令返回的不是订阅模式的客户端的数量, 而是客户端订阅的所有模式的数量总和。

@return

@integer-reply: the number of patterns all the clients are subscribed to. @integer-reply: 客户端订阅的所有模式的数量总和.