# BITFIELD_RO

> Read bitfield values.

Use `BITFIELD_RO` to read one or more bitfield values without modifying the key.

It is the read-only form of [`BITFIELD`](/redis/commands/bitmap/bitfield) and accepts `GET` operations only, so it is safe to run on replicas and from read-only scripts. Each `GET` names an encoding, `u<bits>` for unsigned or `i<bits>` for signed integers, and a bit offset that can be written as `#<n>` to address the n-th field of that width. The reply holds one integer per `GET`, and any part of a field that lies past the end of the stored string reads as zero.

## Syntax

```redis
BITFIELD_RO <key> [GET <encoding> <offset> [GET <encoding> <offset> ...]]
```

## Arguments

| Argument | Required | Repeatable | Description |
| --- | --- | --- | --- |
| `<key>` | Yes | No | Redis key targeted by the command. |
| `GET <encoding> <offset>` | No | Yes | Read the value at `<offset>` using `<encoding>`, such as `u8` or `i16`. Repeat to read several fields. |

## Response

The reply reports the result of the operation. Error replies have the same shape in RESP2 and RESP3 and are surfaced as exceptions by the SDKs below.

| Protocol | Reply |
| --- | --- |
| RESP2 | Array of integer or null replies, one per subcommand |
| RESP3 | Array of integer or null replies, one per subcommand |

<Note>
  Client libraries often decode bulk strings, maps, sets, and numeric strings into language-native values. The table describes the Redis wire reply.
</Note>

## Examples

TCP examples use the TLS `REDIS_URL` from the Upstash console. REST examples use `UPSTASH_REDIS_REST_URL` and `UPSTASH_REDIS_REST_TOKEN`.

<AccordionGroup>

<Accordion title="Redis CLI" icon="terminal">

```bash
BITFIELD_RO my-key GET u8 0
```

</Accordion>

<Accordion title="@upstash/redis" icon="node-js" iconType="brands">

<Note>
  This command is not supported yet in `@upstash/redis`.
</Note>

</Accordion>

<Accordion title="upstash_redis" icon="python" iconType="brands">

```python
from upstash_redis import Redis

redis = Redis.from_env()
result = redis.bitfield_ro("my-key").get("u8", 0).execute()
print(result)
```

</Accordion>

<Accordion title="ioredis" icon="node-js" iconType="brands">

```ts
import Redis from "ioredis";

const redis = new Redis(process.env.REDIS_URL!);
const result = await redis.bitfield_ro("my-key", "GET", "u8", "0");
console.log(result);
```

</Accordion>

<Accordion title="node-redis" icon="node-js" iconType="brands">

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

const client = await createClient({ url: process.env.REDIS_URL })
  .on("error", console.error)
  .connect();
const result = await client.bitFieldRo("my-key", [{ encoding: "u8", offset: 0 }]);
console.log(result);
```

</Accordion>

<Accordion title="redis-py" icon="python" iconType="brands">

```python
import os
import redis

client = redis.from_url(os.environ["REDIS_URL"])
result = client.bitfield_ro("my-key", "u8", 0)
print(result)
```

</Accordion>

<Accordion title="go-redis" icon="golang" iconType="brands">

```go
package main

import (
    "context"
    "fmt"
    "os"

    "github.com/redis/go-redis/v9"
)

func main() {
    opts, err := redis.ParseURL(os.Getenv("REDIS_URL"))
    if err != nil {
        panic(err)
    }
    client := redis.NewClient(opts)
    result, err := client.BitFieldRO(context.Background(), "my-key", "GET", "u8", 0).Result()
    if err != nil {
        panic(err)
    }
    fmt.Println(result)
}
```

</Accordion>

<Accordion title="jedis" icon="java" iconType="brands">

```java
import java.net.URI;

import redis.clients.jedis.Jedis;

try (Jedis jedis = new Jedis(new URI(System.getenv("REDIS_URL")))) {
  Object result = jedis.bitfieldReadonly("my-key", "GET", "u8", "0");
  System.out.println(result);
}
```

</Accordion>

<Accordion title="redis-rs" icon="rust" iconType="brands">

```rust
fn main() -> redis::RedisResult<()> {
    let url = std::env::var("REDIS_URL").expect("REDIS_URL is not set");
    let client = redis::Client::open(url)?;
    let mut connection = client.get_connection()?;

    let mut command = redis::cmd("BITFIELD_RO");
    command.arg("my-key");
    let result: redis::Value = command.query(&mut connection)?;
    println!("{result:?}");
    Ok(())
}
```

</Accordion>

</AccordionGroup>