[Server] Add request handler for resource templates

src/Server/Handler/JsonRpcHandler.php

@@ -86,6 +86,7 @@ public static function make(
                 new Handler\Request\GetPromptHandler($promptGetter),
                 new Handler\Request\ListResourcesHandler($referenceProvider, $paginationLimit),
                 new Handler\Request\ReadResourceHandler($resourceReader),
+                new Handler\Request\ListResourceTemplatesHandler($referenceProvider, $paginationLimit),
                 new Handler\Request\CallToolHandler($toolCaller, $logger),
                 new Handler\Request\ListToolsHandler($referenceProvider, $paginationLimit),
             ],

src/Server/Handler/Request/ListResourceTemplatesHandler.php

@@ -0,0 +1,53 @@
+<?php
+
+/*
+ * This file is part of the official PHP MCP SDK.
+ *
+ * A collaboration between Symfony and the PHP Foundation.
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Mcp\Server\Handler\Request;
+
+use Mcp\Capability\Registry\ReferenceProviderInterface;
+use Mcp\Exception\InvalidCursorException;
+use Mcp\Schema\JsonRpc\HasMethodInterface;
+use Mcp\Schema\JsonRpc\Response;
+use Mcp\Schema\Request\ListResourceTemplatesRequest;
+use Mcp\Schema\Result\ListResourceTemplatesResult;
+use Mcp\Server\Handler\MethodHandlerInterface;
+use Mcp\Server\Session\SessionInterface;
+
+/**
+ * @author Christopher Hertel <[email protected]>
+ */
+final class ListResourceTemplatesHandler implements MethodHandlerInterface
+{
+    public function __construct(
+        private readonly ReferenceProviderInterface $registry,
+        private readonly int $pageSize = 20,
+    ) {
+    }
+
+    public function supports(HasMethodInterface $message): bool
+    {
+        return $message instanceof ListResourceTemplatesRequest;
+    }
+
+    /**
+     * @throws InvalidCursorException
+     */
+    public function handle(ListResourceTemplatesRequest|HasMethodInterface $message, SessionInterface $session): Response
+    {
+        \assert($message instanceof ListResourceTemplatesRequest);
+
+        $page = $this->registry->getResourceTemplates($this->pageSize, $message->cursor);
+
+        return new Response(
+            $message->getId(),
+            new ListResourceTemplatesResult($page->references, $page->nextCursor),
+        );
+    }
+}

tests/Inspector/InspectorSnapshotTestCase.php

@@ -54,7 +54,7 @@ protected static function provideListMethods(): array
         return [
             'Prompt Listing' => ['method' => 'prompts/list'],
             'Resource Listing' => ['method' => 'resources/list'],
-            // 'Resource Template Listing' => ['method' => 'resources/templates/list'],
+            'Resource Template Listing' => ['method' => 'resources/templates/list'],
             'Tool Listing' => ['method' => 'tools/list'],
         ];
     }

tests/Inspector/snapshots/ManualStdioExampleTest-resources_templates_list.json

@@ -0,0 +1,10 @@
+{
+  "resourceTemplates": [
+    {
+      "name": "get_item_details",
+      "uriTemplate": "item://{itemId}/details",
+      "description": "A manually registered resource template.",
+      "mimeType": "application/json"
+    }
+  ]
+}

tests/Inspector/snapshots/StdioCalculatorExampleTest-resources_templates_list.json

@@ -0,0 +1,3 @@
+{
+  "resourceTemplates": []
+}

tests/Unit/Server/Handler/Request/ListResourceTemplatesHandlerTest.php

@@ -0,0 +1,217 @@
+<?php
+
+/*
+ * This file is part of the official PHP MCP SDK.
+ *
+ * A collaboration between Symfony and the PHP Foundation.
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Mcp\Tests\Unit\Server\Handler\Request;
+
+use Mcp\Capability\Registry;
+use Mcp\Exception\InvalidCursorException;
+use Mcp\Schema\Request\ListResourceTemplatesRequest;
+use Mcp\Schema\ResourceTemplate;
+use Mcp\Schema\Result\ListResourceTemplatesResult;
+use Mcp\Server\Handler\Request\ListResourceTemplatesHandler;
+use Mcp\Server\Session\InMemorySessionStore;
+use Mcp\Server\Session\Session;
+use Mcp\Server\Session\SessionInterface;
+use PHPUnit\Framework\TestCase;
+
+class ListResourceTemplatesHandlerTest extends TestCase
+{
+    private Registry $registry;
+    private ListResourceTemplatesHandler $handler;
+    private SessionInterface $session;
+
+    protected function setUp(): void
+    {
+        $this->registry = new Registry();
+        $this->handler = new ListResourceTemplatesHandler($this->registry, pageSize: 3);
+        $this->session = new Session(new InMemorySessionStore());
+    }
+
+    public function testReturnsFirstPageWhenNoCursorProvided(): void
+    {
+        // Arrange
+        $this->addResourcesToRegistry(5);
+        $request = $this->createListResourcesRequest();
+
+        // Act
+        $response = $this->handler->handle($request, $this->session);
+
+        // Assert
+        /** @var ListResourceTemplatesResult $result */
+        $result = $response->result;
+        $this->assertInstanceOf(ListResourceTemplatesResult::class, $result);
+        $this->assertCount(3, $result->resourceTemplates);
+        $this->assertNotNull($result->nextCursor);
+
+        $this->assertEquals('resource://{test}/resource_0', $result->resourceTemplates[0]->uriTemplate);
+        $this->assertEquals('resource://{test}/resource_1', $result->resourceTemplates[1]->uriTemplate);
+        $this->assertEquals('resource://{test}/resource_2', $result->resourceTemplates[2]->uriTemplate);
+    }
+
+    public function testReturnsSecondPageWithCursor(): void
+    {
+        // Arrange
+        $this->addResourcesToRegistry(10);
+        $firstPageRequest = $this->createListResourcesRequest();
+        $firstPageResponse = $this->handler->handle($firstPageRequest, $this->session);
+
+        /** @var ListResourceTemplatesResult $firstPageResult */
+        $firstPageResult = $firstPageResponse->result;
+        $secondPageRequest = $this->createListResourcesRequest(cursor: $firstPageResult->nextCursor);
+
+        // Act
+        $response = $this->handler->handle($secondPageRequest, $this->session);
+
+        // Assert
+        /** @var ListResourceTemplatesResult $result */
+        $result = $response->result;
+        $this->assertInstanceOf(ListResourceTemplatesResult::class, $result);
+        $this->assertCount(3, $result->resourceTemplates);
+        $this->assertNotNull($result->nextCursor);
+
+        $this->assertEquals('resource://{test}/resource_3', $result->resourceTemplates[0]->uriTemplate);
+        $this->assertEquals('resource://{test}/resource_4', $result->resourceTemplates[1]->uriTemplate);
+        $this->assertEquals('resource://{test}/resource_5', $result->resourceTemplates[2]->uriTemplate);
+    }
+
+    public function testReturnsLastPageWithNullCursor(): void
+    {
+        // Arrange
+        $this->addResourcesToRegistry(5);
+        $firstPageRequest = $this->createListResourcesRequest();
+        $firstPageResponse = $this->handler->handle($firstPageRequest, $this->session);
+
+        /** @var ListResourceTemplatesResult $firstPageResult */
+        $firstPageResult = $firstPageResponse->result;
+        $secondPageRequest = $this->createListResourcesRequest(cursor: $firstPageResult->nextCursor);
+
+        // Act
+        $response = $this->handler->handle($secondPageRequest, $this->session);
+
+        // Assert
+        /** @var ListResourceTemplatesResult $result */
+        $result = $response->result;
+        $this->assertInstanceOf(ListResourceTemplatesResult::class, $result);
+        $this->assertCount(2, $result->resourceTemplates);
+        $this->assertNull($result->nextCursor);
+
+        $this->assertEquals('resource://{test}/resource_3', $result->resourceTemplates[0]->uriTemplate);
+        $this->assertEquals('resource://{test}/resource_4', $result->resourceTemplates[1]->uriTemplate);
+    }
+
+    public function testHandlesEmptyRegistry(): void
+    {
+        // Arrange
+        $request = $this->createListResourcesRequest();
+
+        // Act
+        $response = $this->handler->handle($request, $this->session);
+
+        // Assert
+        /** @var ListResourceTemplatesResult $result */
+        $result = $response->result;
+        $this->assertInstanceOf(ListResourceTemplatesResult::class, $result);
+        $this->assertCount(0, $result->resourceTemplates);
+        $this->assertNull($result->nextCursor);
+    }
+
+    public function testThrowsExceptionForInvalidCursor(): void
+    {
+        // Arrange
+        $this->addResourcesToRegistry(5);
+        $request = $this->createListResourcesRequest(cursor: 'invalid-cursor');
+
+        // Assert
+        $this->expectException(InvalidCursorException::class);
+
+        // Act
+        $this->handler->handle($request, $this->session);
+    }
+
+    public function testThrowsExceptionForCursorBeyondBounds(): void
+    {
+        // Arrange
+        $this->addResourcesToRegistry(5);
+        $outOfBoundsCursor = base64_encode('100');
+        $request = $this->createListResourcesRequest(cursor: $outOfBoundsCursor);
+
+        // Assert
+        $this->expectException(InvalidCursorException::class);
+
+        // Act
+        $this->handler->handle($request, $this->session);
+    }
+
+    public function testHandlesCursorAtExactBoundary(): void
+    {
+        // Arrange
+        $this->addResourcesToRegistry(6);
+        $exactBoundaryCursor = base64_encode('6');
+        $request = $this->createListResourcesRequest(cursor: $exactBoundaryCursor);
+
+        // Act
+        $response = $this->handler->handle($request, $this->session);
+
+        // Assert
+        /** @var ListResourceTemplatesResult $result */
+        $result = $response->result;
+        $this->assertInstanceOf(ListResourceTemplatesResult::class, $result);
+        $this->assertCount(0, $result->resourceTemplates);
+        $this->assertNull($result->nextCursor);
+    }
+
+    public function testMaintainsStableCursorsAcrossCalls(): void
+    {
+        // Arrange
+        $this->addResourcesToRegistry(10);
+
+        // Act
+        $request = $this->createListResourcesRequest();
+        $response1 = $this->handler->handle($request, $this->session);
+        $response2 = $this->handler->handle($request, $this->session);
+
+        // Assert
+        /** @var ListResourceTemplatesResult $result1 */
+        $result1 = $response1->result;
+        /** @var ListResourceTemplatesResult $result2 */
+        $result2 = $response2->result;
+        $this->assertEquals($result1->nextCursor, $result2->nextCursor);
+        $this->assertEquals($result1->resourceTemplates, $result2->resourceTemplates);
+    }
+
+    private function addResourcesToRegistry(int $count): void
+    {
+        for ($i = 0; $i < $count; ++$i) {
+            $resourceTemplate = new ResourceTemplate(
+                uriTemplate: "resource://{test}/resource_$i",
+                name: "resource_$i",
+                description: "Test resource $i"
+            );
+            // Use a simple callable as handler
+            $this->registry->registerResourceTemplate($resourceTemplate, fn () => null);
+        }
+    }
+
+    private function createListResourcesRequest(?string $cursor = null): ListResourceTemplatesRequest
+    {
+        $data = [
+            'jsonrpc' => '2.0',
+            'id' => 'test-request-id',
+            'method' => 'resources/list',
+        ];
+
+        if (null !== $cursor) {
+            $data['params'] = ['cursor' => $cursor];
+        }
+
+        return ListResourceTemplatesRequest::fromArray($data);
+    }
+}