qwen-code/packages/chrome-qwen-bridge/native-host/browser-mcp-server.js

#!/usr/bin/env node

/**
 * Browser MCP Server
 * Provides browser tools (read_page, capture_screenshot, etc.) to Qwen CLI
 * Communicates with Native Host via HTTP to get browser data
 */

const http = require('http');
const readline = require('readline');

const BRIDGE_URL = 'http://127.0.0.1:18765';

// MCP Protocol version
const PROTOCOL_VERSION = '2024-11-05';

// Available tools
const TOOLS = [
  {
    name: 'browser_read_page',
    description: 'Read the content of the current browser page. Returns URL, title, text content, links, and images.',
    inputSchema: {
      type: 'object',
      properties: {},
      required: []
    }
  },
  {
    name: 'browser_capture_screenshot',
    description: 'Capture a screenshot of the current browser tab. Returns a base64-encoded PNG image.',
    inputSchema: {
      type: 'object',
      properties: {},
      required: []
    }
  },
  {
    name: 'browser_get_network_logs',
    description: 'Get network request logs from the current browser tab. Useful for debugging API calls.',
    inputSchema: {
      type: 'object',
      properties: {},
      required: []
    }
  },
  {
    name: 'browser_get_console_logs',
    description: 'Get console logs (log, error, warn, info) from the current browser tab.',
    inputSchema: {
      type: 'object',
      properties: {},
      required: []
    }
  }
];

// Send request to Native Host HTTP bridge
async function callBridge(method, params = {}) {
  return new Promise((resolve, reject) => {
    const data = JSON.stringify({ method, params });

    const req = http.request(BRIDGE_URL, {
      method: 'POST',
      headers: {
        'Content-Type': 'application/json',
        'Content-Length': Buffer.byteLength(data)
      }
    }, (res) => {
      let body = '';
      res.on('data', chunk => body += chunk);
      res.on('end', () => {
        try {
          const result = JSON.parse(body);
          if (result.success) {
            resolve(result.data);
          } else {
            reject(new Error(result.error || 'Unknown error'));
          }
        } catch (err) {
          reject(new Error(`Failed to parse response: ${err.message}`));
        }
      });
    });

    req.on('error', (err) => {
      reject(new Error(`Bridge connection failed: ${err.message}. Make sure Chrome extension is running.`));
    });

    req.write(data);
    req.end();
  });
}

// Handle MCP tool calls
async function handleToolCall(name, args) {
  switch (name) {
    case 'browser_read_page': {
      const data = await callBridge('read_page');
      return {
        content: [
          {
            type: 'text',
            text: JSON.stringify({
              url: data.url,
              title: data.title,
              content: data.content?.text || data.content?.markdown || '',
              linksCount: data.links?.length || 0,
              imagesCount: data.images?.length || 0
            }, null, 2)
          }
        ]
      };
    }

    case 'browser_capture_screenshot': {
      const data = await callBridge('capture_screenshot');
      return {
        content: [
          {
            type: 'image',
            data: data.dataUrl?.replace(/^data:image\/png;base64,/, '') || '',
            mimeType: 'image/png'
          }
        ]
      };
    }

    case 'browser_get_network_logs': {
      const data = await callBridge('get_network_logs');
      const logs = data.logs || [];
      const summary = logs.slice(-20).map(log => ({
        method: log.method,
        url: log.params?.request?.url || log.params?.documentURL,
        status: log.params?.response?.status,
        timestamp: log.timestamp
      }));
      return {
        content: [
          {
            type: 'text',
            text: `Network logs (last ${summary.length} entries):\n${JSON.stringify(summary, null, 2)}`
          }
        ]
      };
    }

    case 'browser_get_console_logs': {
      const data = await callBridge('get_console_logs');
      const logs = data.logs || [];
      const formatted = logs.slice(-50).map(log =>
        `[${log.type}] ${log.message}`
      ).join('\n');
      return {
        content: [
          {
            type: 'text',
            text: `Console logs (last ${Math.min(logs.length, 50)} entries):\n${formatted || '(no logs captured)'}`
          }
        ]
      };
    }

    default:
      throw new Error(`Unknown tool: ${name}`);
  }
}

// Send JSON-RPC response
function sendResponse(id, result) {
  const response = {
    jsonrpc: '2.0',
    id,
    result
  };
  console.log(JSON.stringify(response));
}

// Send JSON-RPC error
function sendError(id, code, message) {
  const response = {
    jsonrpc: '2.0',
    id,
    error: { code, message }
  };
  console.log(JSON.stringify(response));
}

// Handle incoming JSON-RPC messages
async function handleMessage(message) {
  const { id, method, params } = message;

  try {
    switch (method) {
      case 'initialize':
        sendResponse(id, {
          protocolVersion: PROTOCOL_VERSION,
          capabilities: {
            tools: {}
          },
          serverInfo: {
            name: 'browser-mcp-server',
            version: '1.0.0'
          }
        });
        break;

      case 'notifications/initialized':
        // No response needed for notifications
        break;

      case 'tools/list':
        sendResponse(id, { tools: TOOLS });
        break;

      case 'tools/call':
        try {
          const result = await handleToolCall(params.name, params.arguments || {});
          sendResponse(id, result);
        } catch (err) {
          sendResponse(id, {
            content: [
              {
                type: 'text',
                text: `Error: ${err.message}`
              }
            ],
            isError: true
          });
        }
        break;

      case 'ping':
        sendResponse(id, {});
        break;

      default:
        if (id !== undefined) {
          sendError(id, -32601, `Method not found: ${method}`);
        }
    }
  } catch (err) {
    if (id !== undefined) {
      sendError(id, -32603, err.message);
    }
  }
}

// Main: Read JSON-RPC messages from stdin
const rl = readline.createInterface({
  input: process.stdin,
  output: process.stdout,
  terminal: false
});

rl.on('line', async (line) => {
  try {
    const message = JSON.parse(line);
    await handleMessage(message);
  } catch (err) {
    // Ignore parse errors
  }
});

rl.on('close', () => {
  process.exit(0);
});

// Handle errors
process.on('uncaughtException', (err) => {
  console.error('Uncaught exception:', err);
});