Use Kestrel for all in-memory HTTP tests

src/ModelContextProtocol.AspNetCore/McpEndpointRouteBuilderExtensions.cs

@@ -1,15 +1,18 @@
 using Microsoft.AspNetCore.Http;
 using Microsoft.AspNetCore.Http.Features;
 using Microsoft.AspNetCore.Routing;
+using Microsoft.AspNetCore.Routing.Patterns;
 using Microsoft.AspNetCore.WebUtilities;
 using Microsoft.Extensions.DependencyInjection;
+using Microsoft.Extensions.Hosting;
 using Microsoft.Extensions.Logging;
 using Microsoft.Extensions.Options;
 using ModelContextProtocol.Protocol.Messages;
 using ModelContextProtocol.Protocol.Transport;
 using ModelContextProtocol.Server;
 using ModelContextProtocol.Utils.Json;
 using System.Collections.Concurrent;
+using System.Diagnostics.CodeAnalysis;
 using System.Security.Cryptography;
 
 namespace Microsoft.AspNetCore.Builder;
@@ -23,53 +26,87 @@ public static class McpEndpointRouteBuilderExtensions
     /// Sets up endpoints for handling MCP HTTP Streaming transport.
     /// </summary>
     /// <param name="endpoints">The web application to attach MCP HTTP endpoints.</param>
-    /// <param name="runSession">Provides an optional asynchronous callback for handling new MCP sessions.</param>
+    /// <param name="pattern">The route pattern prefix to map to.</param>
+    /// <param name="configureOptionsAsync">Configure per-session options.</param>
+    /// <param name="runSessionAsync">Provides an optional asynchronous callback for handling new MCP sessions.</param>
     /// <returns>Returns a builder for configuring additional endpoint conventions like authorization policies.</returns>
-    public static IEndpointConventionBuilder MapMcp(this IEndpointRouteBuilder endpoints, Func<HttpContext, IMcpServer, CancellationToken, Task>? runSession = null)
+    public static IEndpointConventionBuilder MapMcp(
+        this IEndpointRouteBuilder endpoints,
+        [StringSyntax("Route")] string pattern = "",
+        Func<HttpContext, McpServerOptions, CancellationToken, Task>? configureOptionsAsync = null,
+        Func<HttpContext, IMcpServer, CancellationToken, Task>? runSessionAsync = null)
+        => endpoints.MapMcp(RoutePatternFactory.Parse(pattern), configureOptionsAsync, runSessionAsync);
+
+    /// <summary>
+    /// Sets up endpoints for handling MCP HTTP Streaming transport.
+    /// </summary>
+    /// <param name="endpoints">The web application to attach MCP HTTP endpoints.</param>
+    /// <param name="pattern">The route pattern prefix to map to.</param>
+    /// <param name="configureOptionsAsync">Configure per-session options.</param>
+    /// <param name="runSessionAsync">Provides an optional asynchronous callback for handling new MCP sessions.</param>
+    /// <returns>Returns a builder for configuring additional endpoint conventions like authorization policies.</returns>
+    public static IEndpointConventionBuilder MapMcp(this IEndpointRouteBuilder endpoints,
+        RoutePattern pattern,
+        Func<HttpContext, McpServerOptions, CancellationToken, Task>? configureOptionsAsync = null,
+        Func<HttpContext, IMcpServer, CancellationToken, Task>? runSessionAsync = null)
     {
         ConcurrentDictionary<string, SseResponseStreamTransport> _sessions = new(StringComparer.Ordinal);
 
         var loggerFactory = endpoints.ServiceProvider.GetRequiredService<ILoggerFactory>();
-        var mcpServerOptions = endpoints.ServiceProvider.GetRequiredService<IOptions<McpServerOptions>>();
+        var optionsSnapshot = endpoints.ServiceProvider.GetRequiredService<IOptions<McpServerOptions>>();
+        var optionsFactory = endpoints.ServiceProvider.GetRequiredService<IOptionsFactory<McpServerOptions>>();
+        var hostApplicationLifetime = endpoints.ServiceProvider.GetRequiredService<IHostApplicationLifetime>();
 
-        var routeGroup = endpoints.MapGroup("");
+        var routeGroup = endpoints.MapGroup(pattern);
 
         routeGroup.MapGet("/sse", async context =>
         {
-            var response = context.Response;
-            var requestAborted = context.RequestAborted;
+            // If the server is shutting down, we need to cancel all SSE connections immediately without waiting for HostOptions.ShutdownTimeout
+            // which defaults to 30 seconds.
+            using var sseCts = CancellationTokenSource.CreateLinkedTokenSource(context.RequestAborted, hostApplicationLifetime.ApplicationStopping);
+            var cancellationToken = sseCts.Token;
 
+            var response = context.Response;
             response.Headers.ContentType = "text/event-stream";
             response.Headers.CacheControl = "no-cache,no-store";
 
+            // Make sure we disable all response buffering for SSE
+            context.Response.Headers.ContentEncoding = "identity";
+            context.Features.GetRequiredFeature<IHttpResponseBodyFeature>().DisableBuffering();
+
             var sessionId = MakeNewSessionId();
             await using var transport = new SseResponseStreamTransport(response.Body, $"/message?sessionId={sessionId}");
             if (!_sessions.TryAdd(sessionId, transport))
             {
                 throw new Exception($"Unreachable given good entropy! Session with ID '{sessionId}' has already been created.");
             }
 
+            var options = optionsSnapshot.Value;
+            if (configureOptionsAsync is not null)
+            {
+                options = optionsFactory.Create(Options.DefaultName);
+                await configureOptionsAsync.Invoke(context, options, cancellationToken);
+            }
+
             try
             {
-                // Make sure we disable all response buffering for SSE
-                context.Response.Headers.ContentEncoding = "identity";
-                context.Features.GetRequiredFeature<IHttpResponseBodyFeature>().DisableBuffering();
+                var transportTask = transport.RunAsync(cancellationToken);
+                await using var mcpServer = McpServerFactory.Create(transport, options, loggerFactory, endpoints.ServiceProvider);
 
-                var transportTask = transport.RunAsync(cancellationToken: requestAborted);
-                await using var server = McpServerFactory.Create(transport, mcpServerOptions.Value, loggerFactory, endpoints.ServiceProvider);
+                context.Features.Set(mcpServer);
 
                 try
                 {
-                    runSession ??= RunSession;
-                    await runSession(context, server, requestAborted);
+                    runSessionAsync ??= RunSession;
+                    await runSessionAsync(context, mcpServer, cancellationToken);
                 }
                 finally
                 {
                     await transport.DisposeAsync();
                     await transportTask;
                 }
             }
-            catch (OperationCanceledException) when (requestAborted.IsCancellationRequested)
+            catch (OperationCanceledException) when (cancellationToken.IsCancellationRequested)
             {
                 // RequestAborted always triggers when the client disconnects before a complete response body is written,
                 // but this is how SSE connections are typically closed.

src/ModelContextProtocol/Protocol/Transport/SseClientSessionTransport.cs

@@ -151,16 +151,14 @@ private async Task CloseAsync()
     {
         try
         {
-            if (!_connectionCts.IsCancellationRequested)
-            {
-                await _connectionCts.CancelAsync().ConfigureAwait(false);
-                _connectionCts.Dispose();
-            }
+            await _connectionCts.CancelAsync().ConfigureAwait(false);
 
             if (_receiveTask != null)
             {
                 await _receiveTask.ConfigureAwait(false);
             }
+
+            _connectionCts.Dispose();
         }
         finally
         {

tests/ModelContextProtocol.TestSseServer/Program.cs

@@ -1,4 +1,5 @@
-using ModelContextProtocol.Protocol.Types;
+using Microsoft.AspNetCore.Connections;
+using ModelContextProtocol.Protocol.Types;
 using ModelContextProtocol.Server;
 using Serilog;
 using System.Text;
@@ -372,18 +373,34 @@ static CreateMessageRequestParams CreateRequestSamplingParams(string context, st
         };
     }
 
-    public static async Task MainAsync(string[] args, ILoggerProvider? loggerProvider = null, CancellationToken cancellationToken = default)
+    public static async Task MainAsync(string[] args, ILoggerProvider? loggerProvider = null, IConnectionListenerFactory? kestrelTransport = null, CancellationToken cancellationToken = default)
     {
         Console.WriteLine("Starting server...");
 
-        int port = args.Length > 0 &&  uint.TryParse(args[0], out var parsedPort) ? (int)parsedPort : 3001;
-
-        var builder = WebApplication.CreateSlimBuilder(args);
-        builder.WebHost.ConfigureKestrel(options =>
+        var builder = WebApplication.CreateEmptyBuilder(new()
         {
-            options.ListenLocalhost(port);
+            Args = args,
         });
 
+        if (kestrelTransport is null)
+        {
+            int port = args.Length > 0 && uint.TryParse(args[0], out var parsedPort) ? (int)parsedPort : 3001;
+            builder.WebHost.ConfigureKestrel(options =>
+            {
+                options.ListenLocalhost(port);
+            });
+        }
+        else
+        {
+            // Add passed-in transport before calling UseKestrelCore() to avoid the SocketsHttpHandler getting added.
+            builder.Services.AddSingleton(kestrelTransport);
+        }
+
+        builder.WebHost.UseKestrelCore();
+        builder.Services.AddLogging();
+        builder.Services.AddRoutingCore();
+
+        builder.Logging.AddConsole();
         ConfigureSerilog(builder.Logging);
         if (loggerProvider is not null)
         {
@@ -393,6 +410,8 @@ public static async Task MainAsync(string[] args, ILoggerProvider? loggerProvide
         builder.Services.AddMcpServer(ConfigureOptions);
 
         var app = builder.Build();
+        app.UseRouting();
+        app.UseEndpoints(_ => { });
 
         app.MapMcp();
 

tests/ModelContextProtocol.Tests/DockerEverythingServerTests.cs

@@ -0,0 +1,123 @@
+using ModelContextProtocol.Client;
+using ModelContextProtocol.Protocol.Transport;
+using ModelContextProtocol.Protocol.Types;
+using ModelContextProtocol.Tests.Utils;
+
+namespace ModelContextProtocol.Tests;
+
+public class DockerEverythingServerTests(ITestOutputHelper testOutputHelper) : LoggedTest(testOutputHelper)
+{
+    /// <summary>Port number to be grabbed by the next test.</summary>
+    private static int s_nextPort = 3000;
+
+    // If the tests run concurrently against different versions of the runtime, tests can conflict with
+    // each other in the ports set up for interacting with containers. Ensure that such suites running
+    // against different TFMs use different port numbers.
+    private static readonly int s_portOffset = 1000 * (Environment.Version.Major switch
+    {
+        int v when v >= 8 => Environment.Version.Major - 7,
+        _ => 0,
+    });
+
+    private static int CreatePortNumber() => Interlocked.Increment(ref s_nextPort) + s_portOffset;
+
+    public static bool IsDockerAvailable => EverythingSseServerFixture.IsDockerAvailable;
+
+    [Fact(Skip = "docker is not available", SkipUnless = nameof(IsDockerAvailable))]
+    [Trait("Execution", "Manual")]
+    public async Task ConnectAndReceiveMessage_EverythingServerWithSse()
+    {
+        int port = CreatePortNumber();
+
+        await using var fixture = new EverythingSseServerFixture(port);
+        await fixture.StartAsync();
+
+        var defaultOptions = new McpClientOptions
+        {
+            ClientInfo = new() { Name = "IntegrationTestClient", Version = "1.0.0" }
+        };
+
+        var defaultConfig = new McpServerConfig
+        {
+            Id = "everything",
+            Name = "Everything",
+            TransportType = TransportTypes.Sse,
+            TransportOptions = [],
+            Location = $"http://localhost:{port}/sse"
+        };
+
+        // Create client and run tests
+        await using var client = await McpClientFactory.CreateAsync(
+            defaultConfig, 
+            defaultOptions, 
+            loggerFactory: LoggerFactory,
+            cancellationToken: TestContext.Current.CancellationToken);
+        var tools = await client.ListToolsAsync(cancellationToken: TestContext.Current.CancellationToken);
+
+        // assert
+        Assert.NotEmpty(tools);
+    }
+
+    [Fact(Skip = "docker is not available", SkipUnless = nameof(IsDockerAvailable))]
+    [Trait("Execution", "Manual")]
+    public async Task Sampling_Sse_EverythingServer()
+    {
+        int port = CreatePortNumber();
+
+        await using var fixture = new EverythingSseServerFixture(port);
+        await fixture.StartAsync();
+
+        var defaultConfig = new McpServerConfig
+        {
+            Id = "everything",
+            Name = "Everything",
+            TransportType = TransportTypes.Sse,
+            TransportOptions = [],
+            Location = $"http://localhost:{port}/sse"
+        };
+
+        int samplingHandlerCalls = 0;
+        var defaultOptions = new McpClientOptions
+        {
+            Capabilities = new()
+            {
+                Sampling = new()
+                {
+                    SamplingHandler = (_, _, _) =>
+                    {
+                        samplingHandlerCalls++;
+                        return Task.FromResult(new CreateMessageResult
+                        {
+                            Model = "test-model",
+                            Role = "assistant",
+                            Content = new Content
+                            {
+                                Type = "text",
+                                Text = "Test response"
+                            }
+                        });
+                    },
+                },
+            },
+        };
+
+        await using var client = await McpClientFactory.CreateAsync(
+            defaultConfig, 
+            defaultOptions,
+            loggerFactory: LoggerFactory,
+            cancellationToken: TestContext.Current.CancellationToken);
+
+        // Call the server's sampleLLM tool which should trigger our sampling handler
+        var result = await client.CallToolAsync("sampleLLM", new Dictionary<string, object?>
+            {
+                ["prompt"] = "Test prompt",
+                ["maxTokens"] = 100
+            }, cancellationToken: TestContext.Current.CancellationToken);
+
+        // assert
+        Assert.NotNull(result);
+        var textContent = Assert.Single(result.Content);
+        Assert.Equal("text", textContent.Type);
+        Assert.False(string.IsNullOrEmpty(textContent.Text));
+    }
+}

tests/ModelContextProtocol.Tests/Server/MapMcpTests.cs

@@ -0,0 +1,19 @@
+using Microsoft.AspNetCore.Builder;
+using ModelContextProtocol.Tests.Utils;
+
+namespace ModelContextProtocol.Tests.Server;
+
+public class MapMcpTests(ITestOutputHelper testOutputHelper) : KestrelInMemoryTest(testOutputHelper)
+{
+    [Fact]
+    public async Task Allows_Customizing_Route()
+    {
+        await using var app = Builder.Build();
+        app.MapMcp("/mcp");
+        await app.StartAsync(TestContext.Current.CancellationToken);
+
+        using var httpClient = CreateHttpClient();
+        using var response = await httpClient.GetAsync("http://localhost/mcp/sse", HttpCompletionOption.ResponseHeadersRead, TestContext.Current.CancellationToken);
+        response.EnsureSuccessStatusCode();
+    }
+}