leshan-mcp-server/src/handlers/listDevices.js

A standards-compliant MCP server for Leshan LwM2M, exposing Leshan as Model Context Protocol tools.

import { get } from "../utils/leshanClient.js";
import logger from "../utils/loggerConfig.js";

/**
 * List all registered LwM2M devices
 * @returns {Promise<Object>} MCP tool response
 */
export async function listDevices() {
  const operationId = `list-devices-${Date.now()}`;
  
  try {
    logger.info("Listing devices operation started", { operationId });

    const devices = await get("/clients");
    
    if (!Array.isArray(devices)) {
      throw new Error("Invalid response format: expected array of devices");
    }

    const deviceSummary = devices.map(device => ({
      endpoint: device.endpoint,
      registrationId: device.registrationId,
      address: device.address,
      lastUpdate: new Date(device.lastUpdate).toISOString(),
      lifetime: device.lifetime,
      bindingMode: device.bindingMode,
      objectCount: Object.keys(device.availableInstances || {}).length
    }));

    logger.info("Devices listed successfully", {
      operationId,
      deviceCount: devices.length,
      endpoints: devices.map(d => d.endpoint)
    });

    return {
      content: [{
        type: "text",
        text: JSON.stringify({
          success: true,
          operation: "listDevices",
          timestamp: new Date().toISOString(),
          deviceCount: devices.length,
          devices: deviceSummary,
          rawData: devices
        }, null, 2)
      }]
    };

  } catch (error) {
    logger.error("List devices operation failed", {
      operationId,
      error: error.message,
      stack: error.stack
    });

    return {
      content: [{
        type: "text",
        text: JSON.stringify({
          success: false,
          operation: "listDevices",
          error: error.message,
          operationId,
          timestamp: new Date().toISOString()
        }, null, 2)
      }],
      isError: true
    };
  }
}

export default listDevices;