> ## Documentation Index
> Fetch the complete documentation index at: https://wukong.mintlify.site/llms.txt
> Use this file to discover all available pages before exploring further.

# Command Management

> WuKongIM HarmonyOS SDK command management functionality, including CMD message listening and processing

Command management is responsible for handling CMD (command) messages sent from the server. CMD messages can only be sent from the server to the client for parsing, used to handle various system-level instructions and status synchronization.

<Note>
  CMD messages can only be sent from the server, clients cannot actively send CMD messages
</Note>

## Listen for Command Messages

### Basic Listening

```typescript theme={null}
cmdListener = (cmd: WKCMD) => {
  // Handle CMD messages
};

// Add CMD message listener
WKIM.shared.cmdManager().addCmdListener(this.cmdListener);

// Remove listener when exiting page
WKIM.shared.cmdManager().removeCmdListener(this.cmdListener);
```

### Complete Command Listening Management

```typescript theme={null}
interface CMDMessageEvent {
  cmd: WKCMD;
  timestamp: number;
  processed: boolean;
}

class CMDMessageManager {
  private static cmdListeners: Set<(cmd: WKCMD) => void> = new Set();
  private static cmdEventCallbacks: Array<(event: CMDMessageEvent) => void> = [];
  
  // Add command listener
  static addCmdListener(callback: (cmd: WKCMD) => void): void {
    this.cmdListeners.add(callback);
    
    WKIM.shared.cmdManager().addCmdListener((cmd: WKCMD) => {
      // Call callback
      callback(cmd);
      
      // Send to event callbacks
      const event: CMDMessageEvent = {
        cmd,
        timestamp: Date.now(),
        processed: false
      };
      
      this.cmdEventCallbacks.forEach(cb => cb(event));
      
      // Handle common commands
      this.handleCommonCommands(cmd);
      
      console.log('Received command message:', cmd.cmd);
    });
  }
  
  // Remove command listener
  static removeCmdListener(callback: (cmd: WKCMD) => void): void {
    this.cmdListeners.delete(callback);
    WKIM.shared.cmdManager().removeCmdListener(callback);
  }
  
  // Add command event callback
  static addCmdEventCallback(callback: (event: CMDMessageEvent) => void): void {
    this.cmdEventCallbacks.push(callback);
  }
  
  // Remove command event callback
  static removeCmdEventCallback(callback: (event: CMDMessageEvent) => void): void {
    const index = this.cmdEventCallbacks.indexOf(callback);
    if (index > -1) {
      this.cmdEventCallbacks.splice(index, 1);
    }
  }
  
  // Remove all listeners
  static removeAllListeners(): void {
    this.cmdListeners.forEach(callback => {
      WKIM.shared.cmdManager().removeCmdListener(callback);
    });
    this.cmdListeners.clear();
    this.cmdEventCallbacks = [];
  }
  
  // Handle common commands
  private static handleCommonCommands(cmd: WKCMD): void {
    switch (cmd.cmd) {
      case 'syncConversation':
        this.handleSyncConversation(cmd);
        break;
      case 'syncChannelInfo':
        this.handleSyncChannelInfo(cmd);
        break;
      case 'syncChannelMember':
        this.handleSyncChannelMember(cmd);
        break;
      case 'syncMessageExtra':
        this.handleSyncMessageExtra(cmd);
        break;
      case 'syncMessageReaction':
        this.handleSyncMessageReaction(cmd);
        break;
      case 'userStatusUpdate':
        this.handleUserStatusUpdate(cmd);
        break;
      case 'channelUpdate':
        this.handleChannelUpdate(cmd);
        break;
      case 'memberUpdate':
        this.handleMemberUpdate(cmd);
        break;
      default:
        console.log('Unhandled command:', cmd.cmd);
        break;
    }
  }
  
  // Handle sync conversation command
  private static handleSyncConversation(cmd: WKCMD): void {
    console.log('Handle sync conversation command');
    // Trigger conversation sync logic
    // Can call conversation manager's sync method here
  }
  
  // Handle sync channel info command
  private static handleSyncChannelInfo(cmd: WKCMD): void {
    console.log('Handle sync channel info command');
    if (cmd.paramJsonObject) {
      const channelId = cmd.paramJsonObject['channel_id'] as string;
      const channelType = cmd.paramJsonObject['channel_type'] as number;
      
      if (channelId && channelType !== undefined) {
        // Refresh channel info
        WKIM.shared.channelManager().fetchChannelInfo(channelId, channelType);
      }
    }
  }
  
  // Handle sync channel member command
  private static handleSyncChannelMember(cmd: WKCMD): void {
    console.log('Handle sync channel member command');
    // Trigger channel member sync logic
  }
  
  // Handle sync message extra command
  private static handleSyncMessageExtra(cmd: WKCMD): void {
    console.log('Handle sync message extra command');
    // Trigger message extra sync logic
  }
  
  // Handle sync message reaction command
  private static handleSyncMessageReaction(cmd: WKCMD): void {
    console.log('Handle sync message reaction command');
    // Trigger message reaction sync logic
  }
  
  // Handle user status update command
  private static handleUserStatusUpdate(cmd: WKCMD): void {
    console.log('Handle user status update command');
    if (cmd.paramJsonObject) {
      const uid = cmd.paramJsonObject['uid'] as string;
      const online = cmd.paramJsonObject['online'] as number;
      
      if (uid && online !== undefined) {
        // Update user online status
        console.log(`User ${uid} status update: ${online === 1 ? 'online' : 'offline'}`);
      }
    }
  }
  
  // Handle channel update command
  private static handleChannelUpdate(cmd: WKCMD): void {
    console.log('Handle channel update command');
    // Handle channel info changes
  }
  
  // Handle member update command
  private static handleMemberUpdate(cmd: WKCMD): void {
    console.log('Handle member update command');
    // Handle member info changes
  }
  
  // Dispose
  static dispose(): void {
    this.removeAllListeners();
  }
}
```

## Common Command Types

### System Sync Commands

These commands are used to sync various data states:

```typescript theme={null}
class SystemSyncCommands {
  
  // Sync conversation list
  static readonly SYNC_CONVERSATION = 'syncConversation';
  
  // Sync channel info
  static readonly SYNC_CHANNEL_INFO = 'syncChannelInfo';
  
  // Sync channel member
  static readonly SYNC_CHANNEL_MEMBER = 'syncChannelMember';
  
  // Sync message extra
  static readonly SYNC_MESSAGE_EXTRA = 'syncMessageExtra';
  
  // Sync message reaction
  static readonly SYNC_MESSAGE_REACTION = 'syncMessageReaction';
  
  // Handle system sync commands
  static handleSyncCommand(cmd: WKCMD): void {
    switch (cmd.cmd) {
      case this.SYNC_CONVERSATION:
        this.syncConversations(cmd.paramJsonObject);
        break;
      case this.SYNC_CHANNEL_INFO:
        this.syncChannelInfo(cmd.paramJsonObject);
        break;
      case this.SYNC_CHANNEL_MEMBER:
        this.syncChannelMember(cmd.paramJsonObject);
        break;
      case this.SYNC_MESSAGE_EXTRA:
        this.syncMessageExtra(cmd.paramJsonObject);
        break;
      case this.SYNC_MESSAGE_REACTION:
        this.syncMessageReaction(cmd.paramJsonObject);
        break;
    }
  }
  
  private static syncConversations(param?: Record<string, Object>): void {
    // Implement conversation sync logic
    console.log('Sync conversation data');
  }
  
  private static syncChannelInfo(param?: Record<string, Object>): void {
    // Implement channel info sync logic
    console.log('Sync channel info');
  }
  
  private static syncChannelMember(param?: Record<string, Object>): void {
    // Implement channel member sync logic
    console.log('Sync channel member');
  }
  
  private static syncMessageExtra(param?: Record<string, Object>): void {
    // Implement message extra sync logic
    console.log('Sync message extra');
  }
  
  private static syncMessageReaction(param?: Record<string, Object>): void {
    // Implement message reaction sync logic
    console.log('Sync message reaction');
  }
}
```

### Status Update Commands

These commands are used for real-time status updates:

```typescript theme={null}
class StatusUpdateCommands {
  
  // User online status update
  static readonly USER_STATUS_UPDATE = 'userStatusUpdate';
  
  // Channel status update
  static readonly CHANNEL_UPDATE = 'channelUpdate';
  
  // Member status update
  static readonly MEMBER_UPDATE = 'memberUpdate';
  
  // Message status update
  static readonly MESSAGE_UPDATE = 'messageUpdate';
  
  // Handle status update commands
  static handleStatusCommand(cmd: WKCMD): void {
    switch (cmd.cmd) {
      case this.USER_STATUS_UPDATE:
        this.handleUserStatusUpdate(cmd.paramJsonObject);
        break;
      case this.CHANNEL_UPDATE:
        this.handleChannelUpdate(cmd.paramJsonObject);
        break;
      case this.MEMBER_UPDATE:
        this.handleMemberUpdate(cmd.paramJsonObject);
        break;
      case this.MESSAGE_UPDATE:
        this.handleMessageUpdate(cmd.paramJsonObject);
        break;
    }
  }
  
  private static handleUserStatusUpdate(param?: Record<string, Object>): void {
    if (param) {
      const uid = param['uid'] as string;
      const online = param['online'] as number;
      const lastSeen = param['last_seen'] as number;
      
      console.log('User status update:', uid, 'online:', online, 'last seen:', lastSeen);
      
      // Update local user status
      // Can notify UI update through events
    }
  }
  
  private static handleChannelUpdate(param?: Record<string, Object>): void {
    if (param) {
      const channelId = param['channel_id'] as string;
      const channelType = param['channel_type'] as number;
      
      console.log('Channel update:', channelId, 'type:', channelType);
      
      // Refresh channel info
      if (channelId && channelType !== undefined) {
        WKIM.shared.channelManager().fetchChannelInfo(channelId, channelType);
      }
    }
  }
  
  private static handleMemberUpdate(param?: Record<string, Object>): void {
    if (param) {
      const channelId = param['channel_id'] as string;
      const memberUid = param['member_uid'] as string;
      
      console.log('Member update: channel', channelId, 'member', memberUid);
      
      // Refresh member info
      // Trigger member list update
    }
  }
  
  private static handleMessageUpdate(param?: Record<string, Object>): void {
    if (param) {
      const messageId = param['message_id'] as string;
      const action = param['action'] as string;
      
      console.log('Message update:', messageId, 'action:', action);
      
      // Handle message updates (like recall, edit, etc.)
    }
  }
}
```

## Data Structure Description

### WKCMD Command Object

```typescript theme={null}
export class WKCMD {
  cmd: string = '';                                    // Command ID
  paramJsonObject?: Record<string, Object>;           // Command parameters
}
```

### Field Description

| Field             | Type                    | Description                                                         |
| ----------------- | ----------------------- | ------------------------------------------------------------------- |
| `cmd`             | string                  | Command identifier, used to distinguish different types of commands |
| `paramJsonObject` | Record\<string, Object> | Command parameters, can contain any type of data                    |

### Common Command Parameter Formats

#### Sync Command Parameters

```typescript theme={null}
// Sync conversation command parameters
{
  "version": 123456,
  "last_msg_seqs": "1,2,3,4,5",
  "msg_count": 20
}

// Sync channel info command parameters
{
  "channel_id": "channel123",
  "channel_type": 2,
  "version": 123456
}
```

#### Status Update Command Parameters

```typescript theme={null}
// User status update parameters
{
  "uid": "user123",
  "online": 1,
  "last_seen": 1640995200,
  "device_flag": 1
}

// Channel update parameters
{
  "channel_id": "channel123",
  "channel_type": 2,
  "action": "update",
  "fields": ["name", "avatar"]
}
```

## Next Steps

<CardGroup cols={2}>
  <Card title="Reminder Management" icon="bell" href="/en/sdk/wukongim/harmonyos/reminder">
    Learn about @mentions and custom reminder functionality
  </Card>

  <Card title="Advanced Features" icon="cog" href="/en/sdk/wukongim/harmonyos/advance">
    Explore custom messages and extension features
  </Card>

  <Card title="Channel Member Management" icon="users" href="/en/sdk/wukongim/harmonyos/channel_member">
    Return to channel member management functionality
  </Card>

  <Card title="Data Source Configuration" icon="database" href="/en/sdk/wukongim/harmonyos/datasource">
    Configure data sources and sync logic
  </Card>
</CardGroup>