send-command

Implementation Reference

• services/DeviceManager.js:96-153 (handler)

  Core handler implementation that sends the command via WebSocket to the NodeMCU device, waits for response with timeout, and handles errors.

  async sendCommand(deviceId, command, params = {}) {
    const ws = this.connections.get(deviceId);
    
    if (!ws || ws.readyState !== 1) { // WebSocket.OPEN = 1
      throw new Error('Device not connected');
    }
  
    return new Promise((resolve, reject) => {
      try {
        // Generate unique command ID
        const commandId = Date.now().toString(36) + Math.random().toString(36).substr(2, 5);
        
        // Create message
        const message = {
          type: 'command',
          commandId,
          command,
          params
        };
  
        // Set up one-time response handler
        const responseHandler = (event) => {
          try {
            const response = JSON.parse(event.data);
            
            if (response.type === 'commandResponse' && response.commandId === commandId) {
              ws.removeEventListener('message', responseHandler);
              resolve(response.data);
            }
          } catch (error) {
            // Ignore non-JSON messages
          }
        };
  
        // Set timeout for command
        const timeout = setTimeout(() => {
          ws.removeEventListener('message', responseHandler);
          reject(new Error('Command timed out'));
        }, 5000);
  
        // Add response handler
        ws.addEventListener('message', responseHandler);
        
        // Send command
        ws.send(JSON.stringify(message));
        
        // Notify listeners
        this._notifyListeners('commandSent', {
          deviceId,
          command,
          params,
          commandId
        });
      } catch (error) {
        reject(error);
      }
    });
  }

• mcp_server_sdk.js:84-118 (handler)

  MCP SDK tool handler for 'send-command', validates inputs, calls DeviceManager.sendCommand, and formats MCP response.

  server.tool(
    "send-command",
    {
      deviceId: z.string().describe("The ID of the device to send the command to"),
      command: z.string().describe("The command to send (restart, update, status, etc.)"),
      params: z.record(z.any()).optional().describe("Optional parameters for the command")
    },
    async ({ deviceId, command, params = {} }) => {
      try {
        if (!deviceId) {
          throw new Error('Device ID is required');
        }
        
        if (!command) {
          throw new Error('Command is required');
        }
        
        const result = await deviceManager.sendCommand(deviceId, command, params);
        
        return {
          content: [{ 
            type: "text", 
            text: JSON.stringify({
              success: true,
              deviceId,
              command,
              result
            }, null, 2)
          }]
        };
      } catch (error) {
        console.error('Error sending command:', error);
        throw new Error(`Failed to send command: ${error.message}`);
      }
    }

• mcp_server.js:27-42 (schema)

  JSON schema definition for the send-command tool parameters.

  "send-command": {
    description: "Send a command to a NodeMCU device",
    parameters: {
      deviceId: {
        type: "string",
        description: "The ID of the device to send the command to"
      },
      command: {
        type: "string",
        description: "The command to send (restart, update, status, etc.)"
      },
      params: {
        type: "object",
        description: "Optional parameters for the command"
      }
    }

• mcp_server.js:148-162 (handler)

  Custom MCP server wrapper handler for send-command tool.

  async sendCommand(deviceId, command, params) {
    if (!deviceId) {
      throw new Error('Device ID is required');
    }
    
    if (!command) {
      throw new Error('Command is required');
    }
    
    try {
      return await deviceManager.sendCommand(deviceId, command, params);
    } catch (error) {
      throw new Error(`Failed to send command: ${error.message}`);
    }
  }

• mcp_server.js:65-65 (registration)

  Tool definitions (including send-command) registered during MCP initialization.

  tools: this.toolDefinitions