Add ModelContextProtocol.Core package (#428)

src/ModelContextProtocol.Core/Client/StreamClientTransport.cs

@@ -0,0 +1,55 @@
+using Microsoft.Extensions.Logging;
+using ModelContextProtocol.Client;
+
+namespace ModelContextProtocol.Protocol;
+
+/// <summary>
+/// Provides an <see cref="IClientTransport"/> implemented around a pair of input/output streams.
+/// </summary>
+/// <remarks>
+/// This transport is useful for scenarios where you already have established streams for communication,
+/// such as custom network protocols, pipe connections, or for testing purposes. It works with any
+/// readable and writable streams.
+/// </remarks>
+public sealed class StreamClientTransport : IClientTransport
+{
+    private readonly Stream _serverInput;
+    private readonly Stream _serverOutput;
+    private readonly ILoggerFactory? _loggerFactory;
+
+    /// <summary>
+    /// Initializes a new instance of the <see cref="StreamClientTransport"/> class.
+    /// </summary>
+    /// <param name="serverInput">
+    /// The stream representing the connected server's input. 
+    /// Writes to this stream will be sent to the server.
+    /// </param>
+    /// <param name="serverOutput">
+    /// The stream representing the connected server's output.
+    /// Reads from this stream will receive messages from the server.
+    /// </param>
+    /// <param name="loggerFactory">A logger factory for creating loggers.</param>
+    public StreamClientTransport(
+        Stream serverInput, Stream serverOutput, ILoggerFactory? loggerFactory = null)
+    {
+        Throw.IfNull(serverInput);
+        Throw.IfNull(serverOutput);
+
+        _serverInput = serverInput;
+        _serverOutput = serverOutput;
+        _loggerFactory = loggerFactory;
+    }
+
+    /// <inheritdoc />
+    public string Name => "in-memory-stream";
+
+    /// <inheritdoc />
+    public Task<ITransport> ConnectAsync(CancellationToken cancellationToken = default)
+    {
+        return Task.FromResult<ITransport>(new StreamClientSessionTransport(
+            new StreamWriter(_serverInput),
+            new StreamReader(_serverOutput),
+            "Client (stream)",
+            _loggerFactory));
+    }
+}