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250 changes: 244 additions & 6 deletions README.md
Original file line number Diff line number Diff line change
Expand Up @@ -27,24 +27,24 @@ node-redis is a modern, high performance [Redis](https://redis.io) client for No

## Installation

Start a redis-server via docker (or any other method you prefer):
Start a redis via docker:

```bash
docker run -p 6379:6379 -it redis/redis-stack-server:latest
docker run -p 6379:6379 -d redis:8.0-rc1
```

To install node-redis, simply:

```bash
npm install redis
```

> "redis" is the "whole in one" package that includes all the other packages. If you only need a subset of the commands, you can install the individual packages. See the list below.
> "redis" is the "whole in one" package that includes all the other packages. If you only need a subset of the commands,
> you can install the individual packages. See the list below.

## Packages

| Name | Description |
|------------------------------------------------|---------------------------------------------------------------------------------------------|
| ---------------------------------------------- | ------------------------------------------------------------------------------------------- |
| [`redis`](./packages/redis) | The client with all the ["redis-stack"](https://github.com/redis-stack/redis-stack) modules |
| [`@redis/client`](./packages/client) | The base clients (i.e `RedisClient`, `RedisCluster`, etc.) |
| [`@redis/bloom`](./packages/bloom) | [Redis Bloom](https://redis.io/docs/data-types/probabilistic/) commands |
Expand All @@ -53,7 +53,245 @@ npm install redis
| [`@redis/time-series`](./packages/time-series) | [Redis Time-Series](https://redis.io/docs/data-types/timeseries/) commands |
| [`@redis/entraid`](./packages/entraid) | Secure token-based authentication for Redis clients using Microsoft Entra ID |

> Looking for a high-level library to handle object mapping? See [redis-om-node](https://github.com/redis/redis-om-node)!
> Looking for a high-level library to handle object mapping?
> See [redis-om-node](https://github.com/redis/redis-om-node)!


## Usage

### Basic Example

```typescript
import { createClient } from "redis";

const client = await createClient()
.on("error", (err) => console.log("Redis Client Error", err))
.connect();

await client.set("key", "value");
const value = await client.get("key");
client.destroy();
```

The above code connects to localhost on port 6379. To connect to a different host or port, use a connection string in
the format `redis[s]://[[username][:password]@][host][:port][/db-number]`:

```typescript
createClient({
url: "redis://alice:[email protected]:6380",
});
```

You can also use discrete parameters, UNIX sockets, and even TLS to connect. Details can be found in
the [client configuration guide](./docs/client-configuration.md).

To check if the the client is connected and ready to send commands, use `client.isReady` which returns a boolean.
`client.isOpen` is also available. This returns `true` when the client's underlying socket is open, and `false` when it
isn't (for example when the client is still connecting or reconnecting after a network error).

### Redis Commands

There is built-in support for all of the [out-of-the-box Redis commands](https://redis.io/commands). They are exposed
using the raw Redis command names (`HSET`, `HGETALL`, etc.) and a friendlier camel-cased version (`hSet`, `hGetAll`,
etc.):

```typescript
// raw Redis commands
await client.HSET("key", "field", "value");
await client.HGETALL("key");

// friendly JavaScript commands
await client.hSet("key", "field", "value");
await client.hGetAll("key");
```

Modifiers to commands are specified using a JavaScript object:

```typescript
await client.set("key", "value", {
EX: 10,
NX: true,
});
```

Replies will be transformed into useful data structures:

```typescript
await client.hGetAll("key"); // { field1: 'value1', field2: 'value2' }
await client.hVals("key"); // ['value1', 'value2']
```

`Buffer`s are supported as well:

```typescript
await client.hSet("key", "field", Buffer.from("value")); // 'OK'
await client.hGetAll(commandOptions({ returnBuffers: true }), "key"); // { field: <Buffer 76 61 6c 75 65> }
```

### Unsupported Redis Commands

If you want to run commands and/or use arguments that Node Redis doesn't know about (yet!) use `.sendCommand()`:

```typescript
await client.sendCommand(["SET", "key", "value", "NX"]); // 'OK'

await client.sendCommand(["HGETALL", "key"]); // ['key1', 'field1', 'key2', 'field2']
```

### Transactions (Multi/Exec)

Start a [transaction](https://redis.io/topics/transactions) by calling `.multi()`, then chaining your commands. When
you're done, call `.exec()` and you'll get an array back with your results:

```typescript
await client.set("another-key", "another-value");

const [setKeyReply, otherKeyValue] = await client
.multi()
.set("key", "value")
.get("another-key")
.exec(); // ['OK', 'another-value']
```

You can also [watch](https://redis.io/topics/transactions#optimistic-locking-using-check-and-set) keys by calling
`.watch()`. Your transaction will abort if any of the watched keys change.


### Blocking Commands

In v4, `RedisClient` had the ability to create a pool of connections using an "Isolation Pool" on top of the "main"
connection. However, there was no way to use the pool without a "main" connection:

```javascript
const client = await createClient()
.on("error", (err) => console.error(err))
.connect();

await client.ping(client.commandOptions({ isolated: true }));
```

In v5 we've extracted this pool logic into its own class—`RedisClientPool`:

```javascript
const pool = await createClientPool()
.on("error", (err) => console.error(err))
.connect();

await pool.ping();
```


### Pub/Sub

See the [Pub/Sub overview](./docs/pub-sub.md).

### Scan Iterator

[`SCAN`](https://redis.io/commands/scan) results can be looped over
using [async iterators](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Symbol/asyncIterator):

```typescript
for await (const key of client.scanIterator()) {
// use the key!
await client.get(key);
}
```

This works with `HSCAN`, `SSCAN`, and `ZSCAN` too:

```typescript
for await (const { field, value } of client.hScanIterator("hash")) {
}
for await (const member of client.sScanIterator("set")) {
}
for await (const { score, value } of client.zScanIterator("sorted-set")) {
}
```

You can override the default options by providing a configuration object:

```typescript
client.scanIterator({
TYPE: "string", // `SCAN` only
MATCH: "patter*",
COUNT: 100,
});
```

### Disconnecting

The `QUIT` command has been deprecated in Redis 7.2 and should now also be considered deprecated in Node-Redis. Instead
of sending a `QUIT` command to the server, the client can simply close the network connection.

`client.QUIT/quit()` is replaced by `client.close()`. and, to avoid confusion, `client.disconnect()` has been renamed to
`client.destroy()`.

```typescript
client.destroy();
```

### Auto-Pipelining

Node Redis will automatically pipeline requests that are made during the same "tick".

```typescript
client.set("Tm9kZSBSZWRpcw==", "users:1");
client.sAdd("users:1:tokens", "Tm9kZSBSZWRpcw==");
```

Of course, if you don't do something with your Promises you're certain to
get [unhandled Promise exceptions](https://nodejs.org/api/process.html#process_event_unhandledrejection). To take
advantage of auto-pipelining and handle your Promises, use `Promise.all()`.

```typescript
await Promise.all([
client.set("Tm9kZSBSZWRpcw==", "users:1"),
client.sAdd("users:1:tokens", "Tm9kZSBSZWRpcw=="),
]);
```

### Clustering

Check out the [Clustering Guide](./docs/clustering.md) when using Node Redis to connect to a Redis Cluster.

### Events

The Node Redis client class is an Nodejs EventEmitter and it emits an event each time the network status changes:

| Name | When | Listener arguments |
| ----------------------- | ---------------------------------------------------------------------------------- | --------------------------------------------------------- |
| `connect` | Initiating a connection to the server | _No arguments_ |
| `ready` | Client is ready to use | _No arguments_ |
| `end` | Connection has been closed (via `.disconnect()`) | _No arguments_ |
| `error` | An error has occurred—usually a network issue such as "Socket closed unexpectedly" | `(error: Error)` |
| `reconnecting` | Client is trying to reconnect to the server | _No arguments_ |
| `sharded-channel-moved` | See [here](./docs/pub-sub.md#sharded-channel-moved-event) | See [here](./docs/pub-sub.md#sharded-channel-moved-event) |

> :warning: You **MUST** listen to `error` events. If a client doesn't have at least one `error` listener registered and
> an `error` occurs, that error will be thrown and the Node.js process will exit. See the [ > `EventEmitter` docs](https://nodejs.org/api/events.html#events_error_events) for more details.

> The client will not emit [any other events](./docs/v3-to-v4.md#all-the-removed-events) beyond those listed above.

## Supported Redis versions

Node Redis is supported with the following versions of Redis:

| Version | Supported |
| ------- | ------------------ |
| 8.0.z | :heavy_check_mark: |
| 7.0.z | :heavy_check_mark: |
| 6.2.z | :heavy_check_mark: |
| 6.0.z | :heavy_check_mark: |
| 5.0.z | :heavy_check_mark: |
| < 5.0 | :x: |

> Node Redis should work with older versions of Redis, but it is not fully tested and we cannot offer support.

## Migration

- [From V3 to V4](docs/v3-to-v4.md)
- [From V4 to V5](docs/v4-to-v5.md)
- [V5](docs/v5.md)

## Contributing

Expand Down
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