csharp-sdk/tests/ModelContextProtocol.Tests/Utils/TestServerTransport.cs
Stephen Toub caca2ae61d
Overhaul tool handling (#89)
* Overhaul tool handling

- Renames [McpTool{Type}] to [McpServerTool{Type}], in order to distinguish representations of tools on the server from tools on the client.
- Enables [McpServerTool] methods to have arguments injected from DI, as well as a specific set of types from the implementation directly, like IMcpServer.
- Renames WithTools to WithToolsFromAssembly.
- All of the WithToolsXx methods now publish each individual McpServerTool into DI; other code can do so as well. The options setup code gathers all of the tools from DI and combines them into a collection which is then stored in McpServerOptions and used to construct the server.
- The server tools specified via DI as well as manually-provided handlers, using CallToolHandler as a fallback in case the requested tool doesn't exist in the tools collection, and ListToolsHandler augments the information for whatever tools exist.
- The tools are stored in McpServerOptions in a new McpServerToolCollection type, which is a thread-safe container that exposes add/removal notification. Adding/removing tools triggers a change notification that in turn sends a notification to the client about a tools update.
- The ServerOptions are exposed from the server instance.
- Removed cursor-based APIs from McpClientExtensions.
- Changed McpClientExtensions APIs to return `Task<IList<...>` rather than `IAsyncEnumerable<...>`.

I'm sure this will need to evolve further before we're "done", but it's a significant improvement from where we are now. One area I'm not super happy with is the notifying collection; that might work ok for a stdio server, where you can grab the created collection from the server's options and mutate it, but I don't know how well that's going to work for sse servers.

* Make McpServerTool{Collection} extensible

* Fix README.md example

* Add notifications test

* Address feedback
2025-03-25 15:32:46 -04:00

83 lines
2.6 KiB
C#

using System.Threading.Channels;
using ModelContextProtocol.Protocol.Messages;
using ModelContextProtocol.Protocol.Transport;
using ModelContextProtocol.Protocol.Types;
namespace ModelContextProtocol.Tests.Utils;
public class TestServerTransport : IServerTransport
{
private readonly Channel<IJsonRpcMessage> _messageChannel;
private bool _isStarted;
public bool IsConnected => _isStarted;
public ChannelReader<IJsonRpcMessage> MessageReader => _messageChannel;
public List<IJsonRpcMessage> SentMessages { get; } = [];
public Action<IJsonRpcMessage>? OnMessageSent { get; set; }
public TestServerTransport()
{
_messageChannel = Channel.CreateUnbounded<IJsonRpcMessage>(new UnboundedChannelOptions
{
SingleReader = true,
SingleWriter = true,
});
}
public ValueTask DisposeAsync() => ValueTask.CompletedTask;
public async Task SendMessageAsync(IJsonRpcMessage message, CancellationToken cancellationToken = default)
{
SentMessages.Add(message);
if (message is JsonRpcRequest request)
{
if (request.Method == "roots/list")
await ListRoots(request, cancellationToken);
else if (request.Method == "sampling/createMessage")
await Sampling(request, cancellationToken);
else
await WriteMessageAsync(request, cancellationToken);
}
else if (message is JsonRpcNotification notification)
{
await WriteMessageAsync(notification, cancellationToken);
}
OnMessageSent?.Invoke(message);
}
public Task StartListeningAsync(CancellationToken cancellationToken = default)
{
_isStarted = true;
return Task.CompletedTask;
}
private async Task ListRoots(JsonRpcRequest request, CancellationToken cancellationToken)
{
await WriteMessageAsync(new JsonRpcResponse
{
Id = request.Id,
Result = new ModelContextProtocol.Protocol.Types.ListRootsResult
{
Roots = []
}
}, cancellationToken);
}
private async Task Sampling(JsonRpcRequest request, CancellationToken cancellationToken)
{
await WriteMessageAsync(new JsonRpcResponse
{
Id = request.Id,
Result = new CreateMessageResult { Content = new(), Model = "model", Role = "role" }
}, cancellationToken);
}
protected async Task WriteMessageAsync(IJsonRpcMessage message, CancellationToken cancellationToken = default)
{
await _messageChannel.Writer.WriteAsync(message, cancellationToken);
}
}