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Fix server conformance tests for v0.1.11
- Update test_elicitation_sep1330_enums tool to test all 5 enum variants - Add DNS rebinding protection middleware to ConformanceServer Co-authored-by: stephentoub <2642209+stephentoub@users.noreply.github.com>
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‎tests/ModelContextProtocol.ConformanceServer/Program.cs‎

Lines changed: 85 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -3,12 +3,22 @@
33
using ConformanceServer.Tools;
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using ModelContextProtocol.Protocol;
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using System.Collections.Concurrent;
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using System.Net;
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using System.Text.Json;
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namespace ModelContextProtocol.ConformanceServer;
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1011
public class Program
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{
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// Valid localhost values for DNS rebinding protection
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private static readonly HashSet<string> ValidLocalhostHosts = new(StringComparer.OrdinalIgnoreCase)
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{
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"localhost",
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"127.0.0.1",
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"[::1]",
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"::1"
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};
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public static async Task MainAsync(string[] args, ILoggerProvider? loggerProvider = null, CancellationToken cancellationToken = default)
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{
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var builder = WebApplication.CreateBuilder(args);
@@ -92,13 +102,88 @@ public static async Task MainAsync(string[] args, ILoggerProvider? loggerProvide
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var app = builder.Build();
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// DNS rebinding protection middleware
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// Rejects requests with non-localhost Host/Origin headers for localhost servers
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// See: https://github.com/modelcontextprotocol/typescript-sdk/security/advisories/GHSA-w48q-cv73-mx4w
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app.Use(async (context, next) =>
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{
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// Check if this is a localhost server
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var localEndpoint = context.Connection.LocalIpAddress;
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bool isLocalhostServer = localEndpoint == null ||
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IPAddress.IsLoopback(localEndpoint) ||
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localEndpoint.Equals(IPAddress.IPv6Loopback);
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if (isLocalhostServer)
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{
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// Validate Host header
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var host = context.Request.Host.Host;
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if (!IsValidLocalhostHost(host))
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{
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context.Response.StatusCode = StatusCodes.Status403Forbidden;
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await context.Response.WriteAsync("Forbidden: Invalid Host header for localhost server");
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return;
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}
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// Validate Origin header if present
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if (context.Request.Headers.TryGetValue("Origin", out var originValues))
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{
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var origin = originValues.FirstOrDefault();
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if (!string.IsNullOrEmpty(origin) && Uri.TryCreate(origin, UriKind.Absolute, out var originUri))
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{
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if (!IsValidLocalhostHost(originUri.Host))
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{
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context.Response.StatusCode = StatusCodes.Status403Forbidden;
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await context.Response.WriteAsync("Forbidden: Invalid Origin header for localhost server");
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return;
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}
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}
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}
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}
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await next();
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});
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app.MapMcp();
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app.MapGet("/health", () => TypedResults.Ok("Healthy"));
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await app.RunAsync(cancellationToken);
100151
}
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/// <summary>
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/// Checks if the host is a valid localhost value.
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/// Valid values: localhost, 127.0.0.1, [::1], ::1 (with optional port)
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/// </summary>
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private static bool IsValidLocalhostHost(string host)
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{
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if (string.IsNullOrEmpty(host))
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{
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return false;
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}
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// Remove port if present (e.g., "localhost:3001" -> "localhost")
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var hostWithoutPort = host;
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if (host.StartsWith('['))
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{
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// IPv6 address with brackets, e.g., "[::1]:3001"
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var bracketEnd = host.IndexOf(']');
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if (bracketEnd > 0)
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{
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hostWithoutPort = host[..(bracketEnd + 1)];
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}
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}
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else
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{
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var colonIndex = host.LastIndexOf(':');
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if (colonIndex > 0)
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{
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hostWithoutPort = host[..colonIndex];
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}
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}
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return ValidLocalhostHosts.Contains(hostWithoutPort);
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}
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102187
public static async Task Main(string[] args)
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{
104189
await MainAsync(args);

‎tests/ModelContextProtocol.ConformanceServer/Tools/ConformanceTools.cs‎

Lines changed: 44 additions & 9 deletions
Original file line numberDiff line numberDiff line change
@@ -328,23 +328,59 @@ public static async Task<string> ElicitationSep1330Enums(
328328
{
329329
try
330330
{
331+
#pragma warning disable MCP9001 // LegacyTitledEnumSchema is deprecated but required for conformance testing
331332
var schema = new ElicitRequestParams.RequestSchema
332333
{
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Properties =
334335
{
335-
["color"] = new ElicitRequestParams.UntitledSingleSelectEnumSchema()
336+
// 1. Untitled single-select: { type: "string", enum: ["option1", "option2", "option3"] }
337+
["untitledSingle"] = new ElicitRequestParams.UntitledSingleSelectEnumSchema()
336338
{
337-
Description = "Choose a color",
338-
Enum = ["red", "green", "blue"]
339+
Description = "Untitled single-select enum",
340+
Enum = ["option1", "option2", "option3"]
339341
},
340-
["size"] = new ElicitRequestParams.UntitledSingleSelectEnumSchema()
342+
// 2. Titled single-select: { type: "string", oneOf: [{ const: "value1", title: "First Option" }, ...] }
343+
["titledSingle"] = new ElicitRequestParams.TitledSingleSelectEnumSchema()
341344
{
342-
Description = "Choose a size",
343-
Enum = ["small", "medium", "large"],
344-
Default = "medium"
345+
Description = "Titled single-select enum",
346+
OneOf = [
347+
new ElicitRequestParams.EnumSchemaOption { Const = "value1", Title = "First Option" },
348+
new ElicitRequestParams.EnumSchemaOption { Const = "value2", Title = "Second Option" },
349+
new ElicitRequestParams.EnumSchemaOption { Const = "value3", Title = "Third Option" }
350+
]
351+
},
352+
// 3. Legacy titled (deprecated): { type: "string", enum: ["opt1", "opt2", "opt3"], enumNames: ["Option One", "Option Two", "Option Three"] }
353+
["legacyEnum"] = new ElicitRequestParams.LegacyTitledEnumSchema()
354+
{
355+
Description = "Legacy titled enum (deprecated)",
356+
Enum = ["opt1", "opt2", "opt3"],
357+
EnumNames = ["Option One", "Option Two", "Option Three"]
358+
},
359+
// 4. Untitled multi-select: { type: "array", items: { type: "string", enum: ["option1", "option2", "option3"] } }
360+
["untitledMulti"] = new ElicitRequestParams.UntitledMultiSelectEnumSchema()
361+
{
362+
Description = "Untitled multi-select enum",
363+
Items = new ElicitRequestParams.UntitledEnumItemsSchema
364+
{
365+
Enum = ["option1", "option2", "option3"]
366+
}
367+
},
368+
// 5. Titled multi-select: { type: "array", items: { anyOf: [{ const: "value1", title: "First Choice" }, ...] } }
369+
["titledMulti"] = new ElicitRequestParams.TitledMultiSelectEnumSchema()
370+
{
371+
Description = "Titled multi-select enum",
372+
Items = new ElicitRequestParams.TitledEnumItemsSchema
373+
{
374+
AnyOf = [
375+
new ElicitRequestParams.EnumSchemaOption { Const = "value1", Title = "First Choice" },
376+
new ElicitRequestParams.EnumSchemaOption { Const = "value2", Title = "Second Choice" },
377+
new ElicitRequestParams.EnumSchemaOption { Const = "value3", Title = "Third Choice" }
378+
]
379+
}
345380
}
346381
}
347382
};
383+
#pragma warning restore MCP9001
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349385
var result = await server.ElicitAsync(new ElicitRequestParams
350386
{
@@ -354,8 +390,7 @@ public static async Task<string> ElicitationSep1330Enums(
354390

355391
if (result.Action == "accept" && result.Content != null)
356392
{
357-
return $"Accepted with values: color={result.Content["color"].GetString()}, " +
358-
$"size={result.Content["size"].GetString()}";
393+
return $"Elicitation completed: action={result.Action}, content={result.Content}";
359394
}
360395
else
361396
{

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