flutter_mcp_server 0.1.2

flutter_mcp_server: ^0.1.2 copied to clipboard

example/lib/main.dart

import 'package:flutter/material.dart';
import 'dart:async';

import 'package:flutter/services.dart';
import 'package:flutter_mcp_server/flutter_mcp_server.dart';

void main() {
  runApp(const MyApp());
}

class MyApp extends StatefulWidget {
  const MyApp({Key? key}) : super(key: key);

  @override
  State<MyApp> createState() => _MyAppState();
}

class _MyAppState extends State<MyApp> {
  String _platformVersion = 'Unknown';
  bool _serverRunning = false;
  String _statusMessage = 'Server not running';
  List<String> _logs = [];

  McpServer? _server;

  @override
  void initState() {
    super.initState();
    initPlatformState();
  }

  // Platform messages are asynchronous, so we initialize in an async method.
  Future<void> initPlatformState() async {
    String platformVersion;
    // Platform messages may fail, so we use a try/catch PlatformException.
    // We also handle the message potentially returning null.
    try {
      platformVersion =
          await FlutterMcpServer.getPlatformVersion() ?? 'Unknown platform version';
    } on PlatformException {
      platformVersion = 'Failed to get platform version.';
    }

    // If the widget was removed from the tree while the asynchronous platform
    // message was in flight, we want to discard the reply rather than calling
    // setState to update our non-existent appearance.
    if (!mounted) return;

    setState(() {
      _platformVersion = platformVersion;
    });
  }

  void _startServer() {
    // Create MCP server
    _server = FlutterMcpServer.createServer(
      name: 'Example MCP Server',
      version: '1.0.0',
      capabilities: ServerCapabilities(
        tools: true,
        resources: true,
        prompts: true,
      ),
    );

    // Add a simple calculator tool
    _server!.addTool(
      name: 'calculator',
      description: 'Perform basic calculations',
      inputSchema: {
        'type': 'object',
        'properties': {
          'operation': {
            'type': 'string',
            'enum': ['add', 'subtract', 'multiply', 'divide'],
          },
          'a': {'type': 'number'},
          'b': {'type': 'number'},
        },
        'required': ['operation', 'a', 'b'],
      },
      handler: (arguments) async {
        final operation = arguments['operation'] as String;
        final a = arguments['a'] as num;
        final b = arguments['b'] as num;

        _addLog('Calculator tool called: $operation $a $b');

        double result;
        switch (operation) {
          case 'add':
            result = (a + b).toDouble();
            break;
          case 'subtract':
            result = (a - b).toDouble();
            break;
          case 'multiply':
            result = (a * b).toDouble();
            break;
          case 'divide':
            if (b == 0) {
              return CallToolResult(
                content: [TextContent(text: 'Division by zero error')],
                isError: true,
              );
            }
            result = (a / b).toDouble();
            break;
          default:
            return CallToolResult(
              content: [TextContent(text: 'Unknown operation: $operation')],
              isError: true,
            );
        }

        return CallToolResult(
          content: [TextContent(text: result.toString())],
        );
      },
    );

    // Add a time resource
    _server!.addResource(
      uri: 'time://current',
      name: 'Current Time',
      description: 'Get the current date and time',
      mimeType: 'text/plain',
      handler: (uri, params) async {
        _addLog('Time resource accessed: $uri');
        final now = DateTime.now().toString();

        return ReadResourceResult(
          contents: [
            ResourceContent(
              resource: Resource(
                uri: uri.toString(),
                name: 'Current Time',
                mimeType: 'text/plain',
              ),
            ),
          ],
        );
      },
    );

    // Add a greeting prompt
    _server!.addPrompt(
      name: 'greeting',
      description: 'Generate a customized greeting',
      arguments: [
        PromptArgument(
          name: 'name',
          description: 'Name to greet',
          required: true,
        ),
        PromptArgument(
          name: 'language',
          description: 'Language for greeting',
          required: false,
        ),
      ],
      handler: (arguments) async {
        final name = arguments?['name'] as String? ?? 'User';
        final language = arguments?['language'] as String? ?? 'English';

        _addLog('Greeting prompt called: $name in $language');

        String greeting;
        switch (language.toLowerCase()) {
          case 'spanish':
            greeting = '¡Hola, $name!';
            break;
          case 'french':
            greeting = 'Bonjour, $name!';
            break;
          case 'german':
            greeting = 'Guten Tag, $name!';
            break;
          default:
            greeting = 'Hello, $name!';
        }

        return GetPromptResult(
          description: 'A greeting in $language',
          messages: [
            Message(
              role: MessageRole.user,
              content: TextContent(text: greeting),
            ),
          ],
        );
      },
    );

    // Connect to transport
    final transport = FlutterMcpServer.createStdioTransport();
    _server!.connect(transport).then((_) {
      _addLog('Server connected to stdio transport');
      setState(() {
        _serverRunning = true;
        _statusMessage = 'Server running on stdio transport';
      });
    }).catchError((e) {
      _addLog('Error connecting server: $e');
      setState(() {
        _statusMessage = 'Error: $e';
      });
    });
  }

  void _stopServer() {
    if (_server != null) {
      _server!.disconnect().then((_) {
        _addLog('Server disconnected');
        setState(() {
          _serverRunning = false;
          _statusMessage = 'Server stopped';
          _server = null;
        });
      }).catchError((e) {
        _addLog('Error disconnecting server: $e');
      });
    }
  }

  void _addLog(String message) {
    setState(() {
      _logs.add('${DateTime.now().toString()}: $message');
    });
  }

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      home: Scaffold(
        appBar: AppBar(
          title: const Text('Flutter MCP Server Example'),
        ),
        body: Column(
          children: [
            Padding(
              padding: const EdgeInsets.all(16.0),
              child: Text('Running on: $_platformVersion'),
            ),
            Padding(
              padding: const EdgeInsets.all(16.0),
              child: Row(
                mainAxisAlignment: MainAxisAlignment.center,
                children: [
                  ElevatedButton(
                    onPressed: _serverRunning ? null : _startServer,
                    child: const Text('Start Server'),
                  ),
                  const SizedBox(width: 16),
                  ElevatedButton(
                    onPressed: _serverRunning ? _stopServer : null,
                    child: const Text('Stop Server'),
                  ),
                ],
              ),
            ),
            Padding(
              padding: const EdgeInsets.all(16.0),
              child: Text(
                _statusMessage,
                style: TextStyle(
                  fontWeight: FontWeight.bold,
                  color: _serverRunning ? Colors.green : Colors.red,
                ),
              ),
            ),
            Expanded(
              child: Padding(
                padding: const EdgeInsets.all(16.0),
                child: Column(
                  crossAxisAlignment: CrossAxisAlignment.start,
                  children: [
                    const Text(
                      'Server Logs:',
                      style: TextStyle(fontWeight: FontWeight.bold),
                    ),
                    const SizedBox(height: 8),
                    Expanded(
                      child: Container(
                        decoration: BoxDecoration(
                          border: Border.all(color: Colors.grey),
                          borderRadius: BorderRadius.circular(8),
                        ),
                        padding: const EdgeInsets.all(8),
                        child: ListView.builder(
                          itemCount: _logs.length,
                          itemBuilder: (context, index) {
                            return Text(_logs[index]);
                          },
                        ),
                      ),
                    ),
                  ],
                ),
              ),
            ),
          ],
        ),
      ),
    );
  }
}