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Server support (stdio) (#19)

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* Server support (stdio)
* TestServer project
* Refactored McpClient class to extract shared endpoint logic (with McpServer) to a base class, McpJsonRpcEndpoint.
* Improved xmldoc comments for protocol types, mirroring specification schema comments.
* Update README.MD
This commit is contained in:
Peder Holdgaard Pedersen 2025-02-08 16:21:26 +01:00 • committed by GitHub
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1 changed files with 2668 additions and 659 deletions
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286
src/mcpdotnet/Protocol/Transport/StdioTransport.cs
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@ -1,286 +0,0 @@
using System.Diagnostics;
using System.Text.Json;
using McpDotNet.Configuration;
using McpDotNet.Protocol.Messages;
using McpDotNet.Utils.Json;
using Microsoft.Extensions.Logging;
using McpDotNet.Logging;
namespace McpDotNet.Protocol.Transport;
/// <summary>
/// Implements the MCP transport protocol over standard input/output streams.
/// </summary>
public sealed class StdioTransport : TransportBase
{
private readonly StdioTransportOptions _options;
private readonly McpServerConfig _serverConfig;
private readonly ILogger<StdioTransport> _logger;
private readonly JsonSerializerOptions _jsonOptions;
private Process? _process;
private Task? _readTask;
private CancellationTokenSource? _shutdownCts;
private bool _processStarted;
/// <summary>
/// Initializes a new instance of the StdioTransport class.
/// </summary>
/// <param name="options">Configuration options for the transport.</param>
/// <param name="serverConfig">The server configuration for the transport.</param>
/// <param name="loggerFactory">A logger factory for creating loggers.</param>
public StdioTransport(StdioTransportOptions options, McpServerConfig serverConfig, ILoggerFactory loggerFactory)
{
_options = options;
_serverConfig = serverConfig;
_logger = loggerFactory.CreateLogger<StdioTransport>();
_jsonOptions = new JsonSerializerOptions().ConfigureForMcp(loggerFactory);
}
/// <inheritdoc/>
public override async Task ConnectAsync(CancellationToken cancellationToken = default)
{
if (IsConnected)
{
_logger.TransportAlreadyConnected(_serverConfig.Id, _serverConfig.Name);
throw new McpTransportException("Transport is already connected");
}
try
{
_logger.TransportConnecting(_serverConfig.Id, _serverConfig.Name);
_shutdownCts = new CancellationTokenSource();
var startInfo = new ProcessStartInfo
{
FileName = _options.Command,
UseShellExecute = false,
RedirectStandardInput = true,
RedirectStandardOutput = true,
RedirectStandardError = true,
CreateNoWindow = true,
WorkingDirectory = _options.WorkingDirectory ?? Environment.CurrentDirectory,
};
if (_options.Arguments != null)
{
foreach (var arg in _options.Arguments)
{
startInfo.ArgumentList.Add(arg);
}
}
if (_options.EnvironmentVariables != null)
{
foreach (var (key, value) in _options.EnvironmentVariables)
{
startInfo.Environment[key] = value;
}
}
_logger.CreateProcessForTransport(_serverConfig.Id, _serverConfig.Name, _options.Command,
string.Join(", ", startInfo.ArgumentList), string.Join(", ", startInfo.Environment.Select(kvp => kvp.Key + "=" + kvp.Value)),
startInfo.WorkingDirectory, _options.ShutdownTimeout.ToString());
_process = new Process { StartInfo = startInfo };
// Set up error logging
_process.ErrorDataReceived += (sender, args) =>
{
_logger.TransportError(_serverConfig.Id, _serverConfig.Name, args.Data ?? "(no data)");
};
if (!_process.Start())
{
_logger.TransportProcessStartFailed(_serverConfig.Id, _serverConfig.Name);
throw new McpTransportException("Failed to start MCP server process");
}
_logger.TransportProcessStarted(_serverConfig.Id, _serverConfig.Name, _process.Id);
_processStarted = true;
_process.BeginErrorReadLine();
// Start reading messages in the background
_readTask = Task.Run(async () => await ReadMessagesAsync(_shutdownCts.Token));
_logger.TransportReadingMessages(_serverConfig.Id, _serverConfig.Name);
SetConnected(true);
}
catch (Exception ex)
{
_logger.TransportConnectFailed(_serverConfig.Id, _serverConfig.Name, ex);
await CleanupAsync(cancellationToken);
throw new McpTransportException("Failed to connect transport", ex);
}
}
/// <inheritdoc/>
public override async Task SendMessageAsync(IJsonRpcMessage message, CancellationToken cancellationToken = default)
{
if (!IsConnected || _process?.HasExited == true)
{
_logger.TransportNotConnected(_serverConfig.Id, _serverConfig.Name);
throw new McpTransportException("Transport is not connected");
}
string id = "(no id)";
if (message is IJsonRpcMessageWithId messageWithId)
{
id = messageWithId.Id.ToString();
}
try
{
var json = JsonSerializer.Serialize(message, _jsonOptions);
_logger.TransportSendingMessage(_serverConfig.Id, _serverConfig.Name, id, json);
// Write the message followed by a newline
await _process!.StandardInput.WriteLineAsync(json.AsMemory(), cancellationToken);
await _process.StandardInput.FlushAsync();
_logger.TransportSentMessage(_serverConfig.Id, _serverConfig.Name, id);
}
catch (Exception ex)
{
_logger.TransportSendFailed(_serverConfig.Id, _serverConfig.Name, id, ex);
throw new McpTransportException("Failed to send message", ex);
}
}
/// <inheritdoc/>
public override async ValueTask DisposeAsync()
{
await CleanupAsync(CancellationToken.None);
GC.SuppressFinalize(this);
}
private async Task ReadMessagesAsync(CancellationToken cancellationToken)
{
try
{
_logger.TransportEnteringReadMessagesLoop(_serverConfig.Id, _serverConfig.Name);
using var reader = _process!.StandardOutput;
while (!cancellationToken.IsCancellationRequested && !_process.HasExited)
{
_logger.TransportWaitingForMessage(_serverConfig.Id, _serverConfig.Name);
var line = await reader.ReadLineAsync(cancellationToken);
if (line == null)
{
_logger.TransportEndOfStream(_serverConfig.Id, _serverConfig.Name);
break;
}
if (string.IsNullOrWhiteSpace(line))
{
continue;
}
_logger.TransportReceivedMessage(_serverConfig.Id, _serverConfig.Name, line);
try
{
var message = JsonSerializer.Deserialize<IJsonRpcMessage>(line, _jsonOptions);
if (message != null)
{
string messageId = "(no id)";
if (message is IJsonRpcMessageWithId messageWithId)
{
messageId = messageWithId.Id.ToString();
}
_logger.TransportReceivedMessageParsed(_serverConfig.Id, _serverConfig.Name, messageId);
await WriteMessageAsync(message, cancellationToken);
_logger.TransportMessageWritten(_serverConfig.Id, _serverConfig.Name, messageId);
}
else
{
_logger.TransportMessageParseUnexpectedType(_serverConfig.Id, _serverConfig.Name, line);
}
}
catch (JsonException ex)
{
_logger.TransportMessageParseFailed(_serverConfig.Id, _serverConfig.Name, line, ex);
// Continue reading even if we fail to parse a message
}
}
_logger.TransportExitingReadMessagesLoop(_serverConfig.Id, _serverConfig.Name);
}
catch (OperationCanceledException)
{
_logger.TransportReadMessagesCancelled(_serverConfig.Id, _serverConfig.Name);
// Normal shutdown
}
catch (Exception ex)
{
_logger.TransportReadMessagesFailed(_serverConfig.Id, _serverConfig.Name, ex);
}
finally
{
await CleanupAsync(cancellationToken);
}
}
private async Task CleanupAsync(CancellationToken cancellationToken)
{
_logger.TransportCleaningUp(_serverConfig.Id, _serverConfig.Name);
if (_process != null && _processStarted && !_process.HasExited)
{
try
{
// Try to close stdin to signal the process to exit
_logger.TransportClosingStdin(_serverConfig.Id, _serverConfig.Name);
_process.StandardInput.Close();
// Wait for the process to exit
_logger.TransportWaitingForShutdown(_serverConfig.Id, _serverConfig.Name);
if (!_process.WaitForExit((int)_options.ShutdownTimeout.TotalMilliseconds))
{
// If it doesn't exit gracefully, terminate it
_logger.TransportKillingProcess(_serverConfig.Id, _serverConfig.Name);
_process.Kill(true);
}
}
catch (Exception ex)
{
_logger.TransportShutdownFailed(_serverConfig.Id, _serverConfig.Name, ex);
}
_process.Dispose();
_process = null;
}
_shutdownCts?.Cancel();
_shutdownCts?.Dispose();
_shutdownCts = null;
if (_readTask != null)
{
try
{
_logger.TransportWaitingForReadTask(_serverConfig.Id, _serverConfig.Name);
await _readTask.WaitAsync(TimeSpan.FromSeconds(5), cancellationToken);
}
catch (TimeoutException)
{
_logger.TransportCleanupReadTaskTimeout(_serverConfig.Id, _serverConfig.Name);
// Continue with cleanup
}
catch (OperationCanceledException)
{
_logger.TransportCleanupReadTaskCancelled(_serverConfig.Id, _serverConfig.Name);
// Ignore cancellation
}
catch (Exception ex)
{
_logger.TransportCleanupReadTaskFailed(_serverConfig.Id, _serverConfig.Name, ex);
}
_readTask = null;
_logger.TransportReadTaskCleanedUp(_serverConfig.Id, _serverConfig.Name);
}
SetConnected(false);
_logger.TransportCleanedUp(_serverConfig.Id, _serverConfig.Name);
}
}