# Lock (/zh-CN/api-reference/rtm/swift/lock)

> For AI agents: see the complete documentation index at [llms.txt](/llms.txt).

临界资源一次只能供一个进程使用，如果不同的进程之间共享了某个临界资源，则各进程需要采取互斥的方式来防止彼此干扰。RTM 提供一整套 Lock 的方案，通过控制分布式系统的不同进程，你可以解决用户在访问共享资源时的竞争问题。

:::info[信息]
客户端 SDK 具备设置、删除、撤销锁的能力，我们建议你根据实际业务需求控制端侧对锁的操作权限。
:::

## setLock [#setlock]

### 接口描述 [#接口描述]

你需要配置锁的名称、过期时间 TTL 等属性，然后调用 `setLock` 方法进行配置。配置成功后，频道中的所有用户会收到 `lockSet` 类型的 `didReceiveLockEvent` 事件通知，详见[事件监听](/zh-CN/api-reference/rtm/swift/configuration#事件监听)。

### 接口方法 [#接口方法]

你可以通过以下方式调用 `setLock` 方法：

```swift
setLock(
    channelName: String,
    channelType: AgoraRtmChannelType,
    lockName: String,
    ttl: Int32
)   async -> (AgoraRtmCommonResponse?, AgoraRtmErrorInfo?)
```

```swift
setLock(
    channelName: String,
    channelType: AgoraRtmChannelType,
    lockName: String,
    ttl: Int32,
    completion completionBlock: AgoraRtmOperationBlock? = nil
)
```

| 参数 | 类型 | 必填 | 默认值 | 描述 |
| --- | --- | --- | --- | --- |
| `channelName` | String | 必填 | - | 频道名称。 |
| `channelType` | `AgoraRtmChannelType` | 必填 | - | 频道类型。详见 [`AgoraRtmChannelType`](/zh-CN/api-reference/rtm/swift/enumv#channeltype)。 |
| `lockName` | String | 必填 | - | 锁的名称。 |
| `ttl` | Int32 | 选填 | `10` | 设置锁的过期时间。单位为秒，取值范围为 [10,300]。当使用这把锁的用户掉线时，如果用户在过期时间之内重新回到频道，则该用户依旧可以使用锁；否则，该用户的锁会被释放，监听了 `didReceiveLockEvent` 事件通知的用户会收到 `lockReleased` 事件。 |
| `completion` | `AgoraRtmOperationBlock` | 选填 | - | [lock-swift-html-0-5-4 details](#table-slot-lock-swift-html-0-5-4) |

<a id="table-slot-lock-swift-html-0-5-4"></a>

**lock-swift-html-0-5-4 details**

调用结果回调：

- 调用成功：在 `response` 参数中返回 `AgoraRtmCommonResponse` 数据，在 `errorInfo` 参数中返回 `nil`。
- 调用失败：在 `response` 参数中返回 `nil`，在 `errorInfo` 参数中返回错误信息。

### 基本用法 [#基本用法]

```swift tab="async-await"
// async-await
let channelName = "exampleChannel"
let channelType: AgoraRtmChannelType = .message
let lockName = "myLock"
// Lock for 1 hour
let ttl: Int32 = 3600

let (response, error) = await rtmClient.setLock(
    channelName: channelName,
    channelType: channelType,
    lockName: lockName,
    ttl: ttl)
if let errorInfo = error {
    // Handle error
    print("Failed to set lock with error: \(errorInfo.reason)")
} else if let setLockResponse = response {
    // Handle success
    print("Lock set successfully.")
} else {
    // Handle unknown error
    print("Unknown error occurred while setting the lock.")
}
```

```swift tab="callback"
// callback
let channelName = "exampleChannel"
let channelType: AgoraRtmChannelType = .message
let lockName = "myLock"
// Lock for 1 hour
let ttl: Int32 = 3600

rtmClient.setLock(
    channelName: channelName,
    channelType: channelType,
    lockName: lockName,
    ttl: ttl
) { (response, error) in
    if let errorInfo = error {
        // Handle error
        print("Failed to set lock with error: \(errorInfo.reason)")
    } else if let setLockResponse = response {
        // Handle success
        print("Lock set successfully.")
    } else {
        // Handle unknown error
        print("Unknown error occurred while setting the lock.")
    }
}
```

## acquireLock [#acquirelock]

### 接口描述 [#接口描述-1]

成功配置 Lock 后，你可以在客户端调用 `acquireLock` 方法获取锁的使用权。成功获取锁后，频道中的其他用户会收到 `lockAcquired` 类型的 `didReceiveLockEvent` 事件通知，详见[事件监听](/zh-CN/api-reference/rtm/swift/configuration#事件监听)。

### 接口方法 [#接口方法-1]

你可以通过以下方式调用 `acquireLock` 方法：

```swift
acquireLock(
    channelName: String,
    channelType: AgoraRtmChannelType,
    lockName: String,
    retry: Bool
)   async -> (AgoraRtmCommonResponse?, AgoraRtmErrorInfo?)
```

```swift
acquireLock(
    channelName: String,
    channelType: AgoraRtmChannelType,
    lockName: String,
    retry: Bool,
    completion completionBlock: AgoraRtmOperationBlock? = nil
)
```

| 参数 | 类型 | 必填 | 默认值 | 描述 |
| --- | --- | --- | --- | --- |
| `channelName` | String | 必填 | - | 频道名称。 |
| `channelType` | `AgoraRtmChannelType` | 必填 | - | 频道类型。详见 [`AgoraRtmChannelType`](/zh-CN/api-reference/rtm/swift/enumv#channeltype)。 |
| `lockName` | String | 必填 | - | 锁的名称。 |
| `retry` | Bool | 必填 | - | 设置在获取锁失败后是否继续尝试，直到成功获取或退出频道为止。 |
| `completion` | `AgoraRtmOperationBlock` | 选填 | - | [lock-swift-html-1-5-4 details](#table-slot-lock-swift-html-1-5-4) |

<a id="table-slot-lock-swift-html-1-5-4"></a>

**lock-swift-html-1-5-4 details**

调用结果回调：

- 调用成功：在 `response` 参数中返回 `AgoraRtmCommonResponse` 数据，在 `errorInfo` 参数中返回 `nil`。
- 调用失败：在 `response` 参数中返回 `nil`，在 `errorInfo` 参数中返回错误信息。

### 基本用法 [#基本用法-1]

```swift tab="async-await"
// async-await
let channelName = "exampleChannel"
let channelType: AgoraRtmChannelType = .message
let lockName = "myLock"
// Whether to retry acquiring the lock if it fails
let retry = true

let (response, error) = await rtmClient.acquireLock(
    channelName: channelName,
    channelType: channelType,
    lockName: lockName,
    retry: retry
)

if let errorInfo = error {
    // Handle error
    print("Failed to acquire lock with error: \(errorInfo.reason)")
} else if let acquireLockResponse = response {
    // Handle success
    print("Lock acquired successfully.")
} else {
    // Handle unknown error
    print("Unknown error occurred while acquiring the lock.")
}
```

```swift tab="callback"
// callback
let channelName = "exampleChannel"
let channelType: AgoraRtmChannelType = .message
let lockName = "myLock"
// Whether to retry acquiring the lock if it fails
let retry = true

rtmClient.acquireLock(
    channelName: channelName,
    channelType: channelType,
    lockName: lockName,
    retry: retry
) { (response, error) in
    if let errorInfo = error {
        // Handle error
        print("Failed to acquire lock with error: \(errorInfo.reason)")
    } else if let acquireLockResponse = response {
        // Handle success
        print("Lock acquired successfully.")
    } else {
        // Handle unknown error
        print("Unknown error occurred while acquiring the lock.")
    }
}
```

## releaseLock [#releaselock]

### 接口描述 [#接口描述-2]

当用户不再需要持有某把锁时，用户可以在客户端调用 `releaseLock` 方法主动释放锁。成功释放后，频道中的其他用户会收到 `lockReleased` 类型的 `didReceiveLockEvent` 事件，详见[事件监听](/zh-CN/api-reference/rtm/swift/configuration#事件监听)。

此时，如果其他用户想要获取该锁，可以在客户端调用 `acquireLock` 方法参与竞争。新参与获取锁的用户和之前设置 `retry` 属性自动尝试获取锁的用户的竞争优先级相同。

### 接口方法 [#接口方法-2]

你可以通过以下方式调用 `releaseLock` 方法：

```swift
releaseLock(
    channelName: String,
    channelType: AgoraRtmChannelType,
    lockName: String
)   async -> (AgoraRtmCommonResponse?, AgoraRtmErrorInfo?)
```

```swift
releaseLock(
    channelName: String,
    channelType: AgoraRtmChannelType,
    lockName: String,
    completion completionBlock: AgoraRtmOperationBlock? = nil
)
```

| 参数 | 类型 | 必填 | 默认值 | 描述 |
| --- | --- | --- | --- | --- |
| `channelName` | String | 必填 | - | 频道名称。 |
| `channelType` | `AgoraRtmChannelType` | 必填 | - | 频道类型。详见 [`AgoraRtmChannelType`](/zh-CN/api-reference/rtm/swift/enumv#channeltype)。 |
| `lockName` | String | 必填 | - | 锁的名称。 |
| `completion` | `AgoraRtmOperationBlock` | 选填 | - | [lock-swift-html-2-4-4 details](#table-slot-lock-swift-html-2-4-4) |

<a id="table-slot-lock-swift-html-2-4-4"></a>

**lock-swift-html-2-4-4 details**

调用结果回调：

- 调用成功：在 `response` 参数中返回 `AgoraRtmCommonResponse` 数据，在 `errorInfo` 参数中返回 `nil`。
- 调用失败：在 `response` 参数中返回 `nil`，在 `errorInfo` 参数中返回错误信息。

### 基本用法 [#基本用法-2]

```swift tab="async-await"
// async-await
let channelName = "exampleChannel"
let channelType: AgoraRtmChannelType = .message
let lockName = "myLock"

let (response, error) = await rtmClient.releaseLock(
    channelName: channelName,
    channelType: channelType,
    lockName: lockName
)

if let errorInfo = error {
    // Handle error
    print("Failed to acquire lock with error: \(errorInfo.reason)")
} else if let acquireLockResponse = response {
    // Handle success
    print("Lock released successfully.")
} else {
    // Handle unknown error
    print("Unknown error occurred while releasing the lock.")
}
```

```swift tab="callback"
// callback
let channelName = "exampleChannel"
let channelType: AgoraRtmChannelType = .message
let lockName = "myLock"

rtmClient.releaseLock(
    channelName: channelName,
    channelType: channelType,
    lockName: lockName
) { (response, error) in
    if let errorInfo = error {
        // Handle error
        print("Failed to acquire lock with error: \(errorInfo.reason)")
    } else if let acquireLockResponse = response {
        // Handle success
        print("Lock released successfully.")
    } else {
        // Handle unknown error
        print("Unknown error occurred while releasing the lock.")
    }
}
```

## revokeLock [#revokelock]

### 接口描述 [#接口描述-3]

当锁被占用时，为保证你的业务不受影响，你可能需要收回该锁，并让其他用户有机会获取该锁。调用 `revokeLock` 收回被占用的锁。成功收回后，频道中的所有用户会收到 `lockReleased` 类型的 `didReceiveLockEvent` 事件，详见[事件监听](/zh-CN/api-reference/rtm/swift/configuration#事件监听)。

此时，如果其他用户想要获取该锁，可以在客户端调用 `acquireLock` 方法参与竞争。新参与获取锁的用户和之前设置 `retry` 属性自动尝试获取锁的用户的竞争优先级相同。

### 接口方法 [#接口方法-3]

你可以通过以下方式调用 `revokeLock` 方法：

```swift
revokeLock(
    channelName: String,
    channelType: AgoraRtmChannelType,
    lockName: String,
    userId: String
)   async -> (AgoraRtmCommonResponse?, AgoraRtmErrorInfo?)
```

```swift
revokeLock(
    channelName: String,
    channelType: AgoraRtmChannelType,
    lockName: String,
    userId: String,
    completion completionBlock: AgoraRtmOperationBlock? = nil
)
```

| 参数 | 类型 | 必填 | 默认值 | 描述 |
| --- | --- | --- | --- | --- |
| `channelName` | String | 必填 | - | 频道名称。 |
| `channelType` | `AgoraRtmChannelType` | 必填 | - | 频道类型。详见 [`AgoraRtmChannelType`](/zh-CN/api-reference/rtm/swift/enumv#channeltype)。 |
| `lockName` | String | 必填 | - | 锁的名称。 |
| `userId` | String | 必填 | - | 拥有锁的用户 ID。 |
| `completion` | `AgoraRtmOperationBlock` | 选填 | - | [lock-swift-html-3-5-4 details](#table-slot-lock-swift-html-3-5-4) |

<a id="table-slot-lock-swift-html-3-5-4"></a>

**lock-swift-html-3-5-4 details**

调用结果回调：

- 调用成功：在 `response` 参数中返回 `AgoraRtmCommonResponse` 数据，在 `errorInfo` 参数中返回 `nil`。
- 调用失败：在 `response` 参数中返回 `nil`，在 `errorInfo` 参数中返回错误信息。

### 基本用法 [#基本用法-3]

```swift tab="async-await"
// async-await
let channelName = "exampleChannel"
let channelType: AgoraRtmChannelType = .message
let lockName = "myLock"
let userId = "user123" // The ID of the user who holds the lock
let (response, error) = await rtmClient.revokeLock(
    channelName: channelName,
    channelType: channelType,
    lockName: lockName,
    userId: userId
)
if let errorInfo = error {
    // Handle error
    print("Failed to revoke lock with error: \(errorInfo.reason)")
} else if let revokeLockResponse = response {
    // Handle success
    print("Lock revoked successfully.")
} else {
    // Handle unknown error
    print("Unknown error occurred while revoking the lock.")
}
```

```swift tab="callback"
// callback
let channelName = "exampleChannel"
let channelType: AgoraRtmChannelType = .message
let lockName = "myLock"
let userId = "user123" // The ID of the user who holds the lock
rtmClient.revokeLock(
    channelName: channelName,
    channelType: channelType,
    lockName: lockName,
    userId: userId
) { (response, error) in
    if let errorInfo = error {
        // Handle error
        print("Failed to revoke lock with error: \(errorInfo.reason)")
    } else if let revokeLockResponse = response {
        // Handle success
        print("Lock revoked successfully.")
    } else {
        // Handle unknown error
        print("Unknown error occurred while revoking the lock.")
    }
}
```

## getLocks [#getlocks]

### 接口描述 [#接口描述-4]

如果你需要查询频道中锁的数量、名称、使用者、过期时间等信息，在客户端调用 `getLocks` 方法。

### 接口方法 [#接口方法-4]

你可以通过以下方式调用 `getLocks` 方法：

```swift
getLocks(
    channelName: String,
    channelType: AgoraRtmChannelType
)   async -> (AgoraRtmGetLocksResponse?, AgoraRtmErrorInfo?)
```

```swift
getLocks(
    channelName: String,
    channelType: AgoraRtmChannelType,
    completion completionBlock: AgoraRtmGetLocksBlock? = nil
)
```

| 参数 | 类型 | 必填 | 默认值 | 描述 |
| --- | --- | --- | --- | --- |
| `channelName` | String | 必填 | - | 频道名称。 |
| `channelType` | `AgoraRtmChannelType` | 必填 | - | 频道类型。详见 [`AgoraRtmChannelType`](/zh-CN/api-reference/rtm/swift/enumv#channeltype)。 |
| `completion` | `AgoraRtmGetLocksBlock` | 选填 | - | [lock-swift-html-4-3-4 details](#table-slot-lock-swift-html-4-3-4) |

<a id="table-slot-lock-swift-html-4-3-4"></a>

**lock-swift-html-4-3-4 details**

调用结果回调：

- 调用成功：在 `response` 参数中返回 `AgoraRtmGetLocksResponse` 数据，在 `errorInfo` 参数中返回 `nil`。
- 调用失败：在 `response` 参数中返回 `nil`，在 `errorInfo` 参数中返回错误信息。

`AgoraRtmGetLocksResponse` 数据类型包含以下属性：

| 属性             | 类型      | 描述         |
| --------------- | ---------------- | ------------ |
| `lockDetailList` | `[AgoraRtmLockDetail]` | 锁详情数组。 |

`AgoraRtmLockDetail` 数据类型包含以下属性：

| 属性       | 类型     | 描述    |
| --------- | ------- | ------ |
| `LockName` | String | Lock 的名称。        |
| `owner`    | String | 拥有锁的用户 ID。    |
| `ttl`      | Int32      | 锁的过期时间。当使用这把锁的用户掉线时，如果用户在过期时间之内重新回到频道，则该用户依旧可以使用锁；否则，该用户的锁会被释放，监听了 `didReceiveLockEvent` 事件通知的用户会收到 `lockReleased` 事件。 |

### 基本用法 [#基本用法-4]

```swift tab="async-await"
// async-await
let channelName = "exampleChannel"
let channelType: AgoraRtmChannelType = .message
let (response, error) = await rtmClient.getLocks(
    channelName: channelName,
    channelType: channelType
)
if let errorInfo = error {
    // Handle error
    print("Failed to get locks with error: \(errorInfo.reason)")
} else if let getLocksResponse = response {
    // Handle success
    print("Locks retrieved successfully.")
    print("Locks: \(getLocksResponse.locks)")
} else {
    // Handle unknown error
    print("Unknown error occurred while retrieving the locks.")
}
```

```swift tab="callback"
// callback
let channelName = "exampleChannel"
let channelType: AgoraRtmChannelType = .message
rtmClient.getLocks(
    channelName: channelName,
    channelType: channelType
) { (response, error) in
    if let errorInfo = error {
        // Handle error
        print("Failed to get locks with error: \(errorInfo.reason)")
    } else if let getLocksResponse = response {
        // Handle success
        print("Locks retrieved successfully.")
        print("Locks: \(getLocksResponse.locks)")
    } else {
        // Handle unknown error
        print("Unknown error occurred while retrieving the locks.")
    }
}
```

## removeLock [#removelock]

### 接口描述 [#接口描述-5]

如果你不再需要频道中的某把锁，你可以调用 `removeLock` 方法删除该锁。成功删除锁后，频道中的所有用户会收到 `lockRemoved` 类型的 `didReceiveLockEvent` 事件通知，详见[事件监听](/zh-CN/api-reference/rtm/swift/configuration#事件监听)。

### 接口方法 [#接口方法-5]

你可以通过以下方式调用 `removeLock` 方法：

```swift
removeLock(
    channelName: String,
    channelType: AgoraRtmChannelType,
    lockName: String
)   async -> (AgoraRtmCommonResponse?, AgoraRtmErrorInfo?)

```

```swift
removeLock(
    channelName: String,
    channelType: AgoraRtmChannelType,
    lockName: String,
    completion completionBlock: AgoraRtmOperationBlock? = nil
)
```

| 参数 | 类型 | 必填 | 默认值 | 描述 |
| --- | --- | --- | --- | --- |
| `channelName` | String | 必填 | - | 频道名称。 |
| `channelType` | `AgoraRtmChannelType` | 必填 | - | 频道类型。详见 [`AgoraRtmChannelType`](/zh-CN/api-reference/rtm/swift/enumv#channeltype)。 |
| `lockName` | String | 必填 | - | 锁的名称。 |
| `completion` | `AgoraRtmOperationBlock` | 选填 | - | [lock-swift-html-5-4-4 details](#table-slot-lock-swift-html-5-4-4) |

<a id="table-slot-lock-swift-html-5-4-4"></a>

**lock-swift-html-5-4-4 details**

调用结果回调：

- 调用成功：在 `response` 参数中返回 `AgoraRtmCommonResponse` 数据，在 `errorInfo` 参数中返回 `nil`。
- 调用失败：在 `response` 参数中返回 `nil`，在 `errorInfo` 参数中返回错误信息。

### 基本用法 [#基本用法-5]

```swift tab="async-await"
// async-await
let channelName = "exampleChannel"
let channelType: AgoraRtmChannelType = .message
let lockName = "myLock"

let (response, error) = await rtmClient.removeLock(
    channelName: channelName,
    channelType: channelType,
    lockName: lockName
)

if let errorInfo = error {
    // Handle error
    print("Failed to remove lock with error: \(errorInfo.reason)")
} else if let removeLockResponse = response {
    // Handle success
    print("Lock removed successfully.")
} else {
    // Handle unknown error
    print("Unknown error occurred while removing the lock.")
}
```

```swift tab="callback"
// callback
let channelName = "exampleChannel"
let channelType: AgoraRtmChannelType = .message
let lockName = "myLock"

rtmClient.removeLock(
    channelName: channelName,
    channelType: channelType,
    lockName: lockName
) { (response, error) in
    if let errorInfo = error {
        // Handle error
        print("Failed to remove lock with error: \(errorInfo.reason)")
    } else if let removeLockResponse = response {
        // Handle success
        print("Lock removed successfully.")
    } else {
        // Handle unknown error
        print("Unknown error occurred while removing the lock.")
    }
}
```