Initial commit

src/mcpdotnet/Protocol/Transport/TransportBase.cs

@@ -0,0 +1,77 @@
+// Protocol/Transport/IMcpTransport.cs
+namespace McpDotNet.Protocol.Transport;
+
+using System.Text.Json;
+using System.Threading.Channels;
+using global::McpDotNet.Protocol.Messages;
+using McpDotNet.Utils.Json;
+
+// Protocol/Transport/TransportBase.cs
+
+/// <summary>
+/// Base class for implementing MCP transports with common functionality.
+/// </summary>
+public abstract class TransportBase : IMcpTransport
+{
+    private readonly Channel<IJsonRpcMessage> _messageChannel;
+    private bool _isConnected;
+    private readonly JsonSerializerOptions _jsonOptions = new JsonSerializerOptions().ConfigureForMcp();
+
+    protected TransportBase()
+    {
+        // Unbounded channel to prevent blocking on writes
+        _messageChannel = Channel.CreateUnbounded<IJsonRpcMessage>(new UnboundedChannelOptions
+        {
+            SingleReader = true,
+            SingleWriter = true,
+        });
+    }
+
+    /// <inheritdoc/>
+    public bool IsConnected => _isConnected;
+
+    /// <inheritdoc/>
+    public ChannelReader<IJsonRpcMessage> MessageReader => _messageChannel.Reader;
+
+    /// <inheritdoc/>
+    public abstract Task ConnectAsync(CancellationToken cancellationToken = default);
+
+    /// <inheritdoc/>
+    public abstract Task SendMessageAsync(IJsonRpcMessage message, CancellationToken cancellationToken = default);
+
+    /// <inheritdoc/>
+    public abstract ValueTask DisposeAsync();
+
+    /// <summary>
+    /// Writes a message to the message channel.
+    /// </summary>
+    /// <param name="message">The message to write.</param>
+    /// <param name="cancellationToken">Token to cancel the operation.</param>
+    protected async Task WriteMessageAsync(IJsonRpcMessage message, CancellationToken cancellationToken = default)
+    {
+        if (!_isConnected)
+        {
+            throw new McpTransportException("Transport is not connected");
+        }
+
+        await _messageChannel.Writer.WriteAsync(message, cancellationToken);
+    }
+
+    /// <summary>
+    /// Sets the connected state of the transport.
+    /// </summary>
+    /// <param name="isConnected">Whether the transport is connected.</param>
+    protected void SetConnected(bool isConnected)
+    {
+        if (_isConnected == isConnected)
+        {
+            return;
+        }
+
+        _isConnected = isConnected;
+        if (!isConnected)
+        {
+            _messageChannel.Writer.Complete();
+        }
+    }
+}