DotNet MCP Server Demo

using System.Text; using System.Text.Json; namespace MCPDemo.Client { public class McpClient { private readonly HttpClient _httpClient; private readonly string _baseUrl; public McpClient(string baseUrl, string username, string password) { _baseUrl = baseUrl; _httpClient = new HttpClient(); // Set up Basic Authentication var credentials = Convert.ToBase64String(Encoding.UTF8.GetBytes($"{username}:{password}")); _httpClient.DefaultRequestHeaders.Authorization = new System.Net.Http.Headers.AuthenticationHeaderValue("Basic", credentials); } public async Task<T?> SendMcpMessageAsync<T>(object message) { var json = JsonSerializer.Serialize(message, new JsonSerializerOptions { PropertyNamingPolicy = JsonNamingPolicy.CamelCase }); var content = new StringContent(json, Encoding.UTF8, "application/json"); var response = await _httpClient.PostAsync($"{_baseUrl}/api/mcp/message", content); response.EnsureSuccessStatusCode(); var responseJson = await response.Content.ReadAsStringAsync(); return JsonSerializer.Deserialize<T>(responseJson, new JsonSerializerOptions { PropertyNamingPolicy = JsonNamingPolicy.CamelCase }); } public async Task<object?> GetToolsAsync() { var response = await _httpClient.GetAsync($"{_baseUrl}/api/mcp/tools"); response.EnsureSuccessStatusCode(); var json = await response.Content.ReadAsStringAsync(); return JsonSerializer.Deserialize<object>(json); } public void Dispose() { _httpClient?.Dispose(); } } // Example usage public class Program { public static async Task Main(string[] args) { var client = new McpClient("http://localhost:5000", "admin", "password123"); try { // Initialize the MCP server var initMessage = new { jsonrpc = "2.0", id = "1", method = "initialize", @params = new { protocolVersion = "2024-11-05", capabilities = new { }, clientInfo = new { name = "C# MCP Client", version = "1.0.0" } } }; Console.WriteLine("Initializing MCP server..."); var initResponse = await client.SendMcpMessageAsync<object>(initMessage); Console.WriteLine($"Init Response: {JsonSerializer.Serialize(initResponse, new JsonSerializerOptions { WriteIndented = true })}"); // Call the echo tool var echoMessage = new { jsonrpc = "2.0", id = "2", method = "tools/call", @params = new { name = "echo", arguments = new { message = "Hello from C# client!" } } }; Console.WriteLine("\nCalling echo tool..."); var echoResponse = await client.SendMcpMessageAsync<object>(echoMessage); Console.WriteLine($"Echo Response: {JsonSerializer.Serialize(echoResponse, new JsonSerializerOptions { WriteIndented = true })}"); // Call the calculator tool var calcMessage = new { jsonrpc = "2.0", id = "3", method = "tools/call", @params = new { name = "calculate", arguments = new { operation = "multiply", a = 6, b = 7 } } }; Console.WriteLine("\nCalling calculator tool..."); var calcResponse = await client.SendMcpMessageAsync<object>(calcMessage); Console.WriteLine($"Calculator Response: {JsonSerializer.Serialize(calcResponse, new JsonSerializerOptions { WriteIndented = true })}"); // Get available tools Console.WriteLine("\nGetting available tools..."); var tools = await client.GetToolsAsync(); Console.WriteLine($"Available Tools: {JsonSerializer.Serialize(tools, new JsonSerializerOptions { WriteIndented = true })}"); } catch (Exception ex) { Console.WriteLine($"Error: {ex.Message}"); } finally { client.Dispose(); } Console.WriteLine("\nPress any key to exit..."); Console.ReadKey(); } } }