Add ModelContextProtocol.Core package (#428)

src/ModelContextProtocol.Core/Server/DelegatingMcpServerResource.cs

@@ -0,0 +1,34 @@
+using ModelContextProtocol.Protocol;
+
+namespace ModelContextProtocol.Server;
+
+/// <summary>Provides an <see cref="McpServerResource"/> that delegates all operations to an inner <see cref="McpServerResource"/>.</summary>
+/// <remarks>
+/// This is recommended as a base type when building resources that can be chained around an underlying <see cref="McpServerResource"/>.
+/// The default implementation simply passes each call to the inner resource instance.
+/// </remarks>
+public abstract class DelegatingMcpServerResource : McpServerResource
+{
+    private readonly McpServerResource _innerResource;
+
+    /// <summary>Initializes a new instance of the <see cref="DelegatingMcpServerResource"/> class around the specified <paramref name="innerResource"/>.</summary>
+    /// <param name="innerResource">The inner resource wrapped by this delegating resource.</param>
+    protected DelegatingMcpServerResource(McpServerResource innerResource)
+    {
+        Throw.IfNull(innerResource);
+        _innerResource = innerResource;
+    }
+
+    /// <inheritdoc />
+    public override Resource? ProtocolResource => _innerResource.ProtocolResource;
+
+    /// <inheritdoc />
+    public override ResourceTemplate ProtocolResourceTemplate => _innerResource.ProtocolResourceTemplate;
+
+    /// <inheritdoc />
+    public override ValueTask<ReadResourceResult?> ReadAsync(RequestContext<ReadResourceRequestParams> request, CancellationToken cancellationToken = default) => 
+        _innerResource.ReadAsync(request, cancellationToken);
+
+    /// <inheritdoc />
+    public override string ToString() => _innerResource.ToString();
+}