You've already forked node-redis
mirror of
https://github.com/redis/node-redis.git
synced 2025-07-31 05:44:24 +03:00
b2d35c5286
RESP3 Support - Some commands responses in RESP3 aren't stable yet and therefore return an "untyped" ReplyUnion. Sentinel TypeMapping Correctly types Multi commands Note: some API changes to be further documented in v4-to-v5.md
93 lines
2.6 KiB
Markdown
93 lines
2.6 KiB
Markdown
# Pub/Sub
|
|
|
|
The Pub/Sub API is implemented by `RedisClient`, `RedisCluster`, and `RedisSentinel`.
|
|
|
|
## Pub/Sub with `RedisClient`
|
|
|
|
### RESP2
|
|
|
|
Using RESP2, Pub/Sub "takes over" the connection (a client with subscriptions will not execute commands), therefore it requires a dedicated connection. You can easily get one by `.duplicate()`ing an existing `RedisClient`:
|
|
|
|
```javascript
|
|
const subscriber = client.duplicate();
|
|
subscriber.on('error', err => console.error(err));
|
|
await subscriber.connect();
|
|
```
|
|
|
|
> When working with either `RedisCluster` or `RedisSentinel`, this is handled automatically for you.
|
|
|
|
### `sharded-channel-moved` event
|
|
|
|
`RedisClient` emits the `sharded-channel-moved` event when the ["cluster slot"](https://redis.io/docs/reference/cluster-spec/#key-distribution-model) of a subscribed [Sharded Pub/Sub](https://redis.io/docs/manual/pubsub/#sharded-pubsub) channel has been moved to another shard.
|
|
|
|
The event listener signature is as follows:
|
|
```typescript
|
|
(
|
|
channel: string,
|
|
listeners: {
|
|
buffers: Set<Listener>;
|
|
strings: Set<Listener>;
|
|
}
|
|
)
|
|
```
|
|
|
|
> When working with `RedisCluster`, this is handled automatically for you.
|
|
|
|
## Subscribing
|
|
|
|
```javascript
|
|
const listener = (message, channel) => console.log(message, channel);
|
|
await client.subscribe('channel', listener);
|
|
await client.pSubscribe('channe*', listener);
|
|
// Use sSubscribe for sharded Pub/Sub:
|
|
await client.sSubscribe('channel', listener);
|
|
```
|
|
|
|
> ⚠️ Subscribing to the same channel more than once will create multiple listeners, each of which will be called when a message is received.
|
|
|
|
## Publishing
|
|
|
|
```javascript
|
|
await client.publish('channel', 'message');
|
|
// Use sPublish for sharded Pub/Sub:
|
|
await client.sPublish('channel', 'message');
|
|
```
|
|
|
|
## Unsubscribing
|
|
|
|
The code below unsubscribes all listeners from all channels.
|
|
|
|
```javascript
|
|
await client.unsubscribe();
|
|
await client.pUnsubscribe();
|
|
// Use sUnsubscribe for sharded Pub/Sub:
|
|
await client.sUnsubscribe();
|
|
```
|
|
|
|
To unsubscribe from specific channels:
|
|
|
|
```javascript
|
|
await client.unsubscribe('channel');
|
|
await client.unsubscribe(['1', '2']);
|
|
```
|
|
|
|
To unsubscribe a specific listener:
|
|
|
|
```javascript
|
|
await client.unsubscribe('channel', listener);
|
|
```
|
|
|
|
## Buffers
|
|
|
|
Publishing and subscribing using `Buffer`s is also supported:
|
|
|
|
```javascript
|
|
await subscriber.subscribe('channel', message => {
|
|
console.log(message); // <Buffer 6d 65 73 73 61 67 65>
|
|
}, true); // true = subscribe in `Buffer` mode.
|
|
|
|
await subscriber.publish(Buffer.from('channel'), Buffer.from('message'));
|
|
```
|
|
|
|
> NOTE: Buffers and strings are supported both for the channel name and the message. You can mix and match these as desired.
|