Add ModelContextProtocol.Core package (#428)

src/ModelContextProtocol.Core/Protocol/ResourceTemplate.cs

@@ -0,0 +1,93 @@
+using System.Text.Json.Serialization;
+
+namespace ModelContextProtocol.Protocol;
+
+/// <summary>
+/// Represents a known resource template that the server is capable of reading.
+/// </summary>
+/// <remarks>
+/// Resource templates provide metadata about resources available on the server,
+/// including how to construct URIs for those resources.
+/// </remarks>
+public class ResourceTemplate
+{
+    /// <summary>
+    /// Gets or sets the URI template (according to RFC 6570) that can be used to construct resource URIs.
+    /// </summary>
+    [JsonPropertyName("uriTemplate")]
+    public required string UriTemplate { get; init; }
+
+    /// <summary>
+    /// Gets or sets a human-readable name for this resource template.
+    /// </summary>
+    [JsonPropertyName("name")]
+    public required string Name { get; init; }
+
+    /// <summary>
+    /// Gets or sets a description of what this resource template represents.
+    /// </summary>
+    /// <remarks>
+    /// <para>
+    /// This description helps clients understand the purpose and content of resources
+    /// that can be generated from this template. It can be used by client applications
+    /// to provide context about available resource types or to display in user interfaces.
+    /// </para>
+    /// <para>
+    /// For AI models, this description can serve as a hint about when and how to use
+    /// the resource template, enhancing the model's ability to generate appropriate URIs.
+    /// </para>
+    /// </remarks>
+    [JsonPropertyName("description")]
+    public string? Description { get; init; }
+
+    /// <summary>
+    /// Gets or sets the MIME type of this resource template, if known.
+    /// </summary>
+    /// <remarks>
+    /// <para>
+    /// Specifies the expected format of resources that can be generated from this template.
+    /// This helps clients understand what type of content to expect when accessing resources
+    /// created using this template.
+    /// </para>
+    /// <para>
+    /// Common MIME types include "text/plain" for plain text, "application/pdf" for PDF documents,
+    /// "image/png" for PNG images, or "application/json" for JSON data.
+    /// </para>
+    /// </remarks>
+    [JsonPropertyName("mimeType")]
+    public string? MimeType { get; init; }
+
+    /// <summary>
+    /// Gets or sets optional annotations for the resource template.
+    /// </summary>
+    /// <remarks>
+    /// These annotations can be used to specify the intended audience (<see cref="Role.User"/>, <see cref="Role.Assistant"/>, or both)
+    /// and the priority level of the resource template. Clients can use this information to filter
+    /// or prioritize resource templates for different roles.
+    /// </remarks>
+    [JsonPropertyName("annotations")]
+    public Annotations? Annotations { get; init; }
+
+    /// <summary>Gets whether <see cref="UriTemplate"/> contains any template expressions.</summary>
+    [JsonIgnore]
+    public bool IsTemplated => UriTemplate.Contains('{');
+
+    /// <summary>Converts the <see cref="ResourceTemplate"/> into a <see cref="Resource"/>.</summary>
+    /// <returns>A <see cref="Resource"/> if <see cref="IsTemplated"/> is <see langword="false"/>; otherwise, <see langword="null"/>.</returns>
+    public Resource? AsResource()
+    {
+        if (IsTemplated)
+        {
+            return null;
+        }
+
+        return new()
+        {
+            Uri = UriTemplate,
+            Name = Name,
+            Description = Description,
+            MimeType = MimeType,
+            Annotations = Annotations,
+        };
+    }
+}