improve discoverer dependency

Author: soyuka

src/Capability/Discovery/CachedDiscoverer.php

@@ -20,14 +20,17 @@
  * This decorator caches the results of file system operations and reflection
  * to improve performance when discovery is called multiple times.
  *
+ * @internal
+ * @final
+ *
  * @author Xentixar <xentixar@gmail.com>
  */
-class CachedDiscoverer
+class CachedDiscoverer implements DiscovererInterface
 {
     private const CACHE_PREFIX = 'mcp_discovery_';
 
     public function __construct(
-        private readonly Discoverer $discoverer,
+        private readonly DiscovererInterface $discoverer,
         private readonly CacheInterface $cache,
         private readonly LoggerInterface $logger,
     ) {

src/Capability/Discovery/Discoverer.php

@@ -42,9 +42,12 @@
  *     resourceTemplates: int,
  * }
  *
+ * @internal
+ * @final
+ *
  * @author Kyrian Obikwelu <koshnawaza@gmail.com>
  */
-class Discoverer
+class Discoverer implements DiscovererInterface
 {
     public function __construct(
         private readonly LoggerInterface $logger = new NullLogger(),

src/Capability/Discovery/DiscovererInterface.php

@@ -0,0 +1,36 @@
+<?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\Capability\Discovery;
+
+/**
+ * Discovers MCP elements (tools, resources, prompts, resource templates) in directories.
+ *
+ * Implementations can use different strategies:
+ * - File system scanning with reflection
+ * - Cached discovery
+ * - Pre-configured discovery
+ *
+ * @internal
+ *
+ * @author Antoine Bluchet <soyuka@gmail.com>
+ */
+interface DiscovererInterface
+{
+    /**
+     * Discover MCP elements in the specified directories and return the discovery state.
+     *
+     * @param string        $basePath    the base path for resolving directories
+     * @param array<string> $directories list of directories (relative to base path) to scan
+     * @param array<string> $excludeDirs list of directories (relative to base path) to exclude from the scan
+     */
+    public function discover(string $basePath, array $directories, array $excludeDirs = []): DiscoveryState;
+}

src/Capability/Registry/Loader/DiscoveryLoader.php

@@ -11,12 +11,8 @@
 
 namespace Mcp\Capability\Registry\Loader;
 
-use Mcp\Capability\Discovery\CachedDiscoverer;
-use Mcp\Capability\Discovery\Discoverer;
-use Mcp\Capability\Discovery\SchemaGeneratorInterface;
+use Mcp\Capability\Discovery\DiscovererInterface;
 use Mcp\Capability\RegistryInterface;
-use Psr\Log\LoggerInterface;
-use Psr\SimpleCache\CacheInterface;
 
 /**
  * @author Antoine Bluchet <soyuka@gmail.com>
@@ -31,22 +27,13 @@ public function __construct(
         private string $basePath,
         private array $scanDirs,
         private array $excludeDirs,
-        private LoggerInterface $logger,
-        private ?CacheInterface $cache = null,
-        private ?SchemaGeneratorInterface $schemaGenerator = null,
+        private DiscovererInterface $discoverer,
     ) {
     }
 
     public function load(RegistryInterface $registry): void
     {
-        // This now encapsulates the discovery process
-        $discoverer = new Discoverer($this->logger, null, $this->schemaGenerator);
-
-        $cachedDiscoverer = $this->cache
-            ? new CachedDiscoverer($discoverer, $this->cache, $this->logger)
-            : $discoverer;
-
-        $discoveryState = $cachedDiscoverer->discover($this->basePath, $this->scanDirs, $this->excludeDirs);
+        $discoveryState = $this->discoverer->discover($this->basePath, $this->scanDirs, $this->excludeDirs);
 
         $registry->setDiscoveryState($discoveryState);
     }

src/Server/Builder.php

@@ -11,6 +11,7 @@
 
 namespace Mcp\Server;
 
+use Mcp\Capability\Discovery\DiscovererInterface;
 use Mcp\Capability\Discovery\SchemaGeneratorInterface;
 use Mcp\Capability\Registry;
 use Mcp\Capability\Registry\Container;
@@ -61,6 +62,8 @@ final class Builder
 
     private ?SchemaGeneratorInterface $schemaGenerator = null;
 
+    private ?DiscovererInterface $discoverer = null;
+
     private ?SessionFactoryInterface $sessionFactory = null;
 
     private ?SessionStoreInterface $sessionStore = null;
@@ -296,6 +299,13 @@ public function setSchemaGenerator(SchemaGeneratorInterface $schemaGenerator): s
         return $this;
     }
 
+    public function setDiscoverer(DiscovererInterface $discoverer): self
+    {
+        $this->discoverer = $discoverer;
+
+        return $this;
+    }
+
     public function setSession(
         SessionStoreInterface $sessionStore,
         SessionFactoryInterface $sessionFactory = new SessionFactory(),
@@ -480,7 +490,8 @@ public function build(): Server
         ];
 
         if (null !== $this->discoveryBasePath) {
-            $loaders[] = new DiscoveryLoader($this->discoveryBasePath, $this->discoveryScanDirs, $this->discoveryExcludeDirs, $logger, $this->discoveryCache, $this->schemaGenerator);
+            $discoverer = $this->discoverer ?? $this->createDiscoverer($logger);
+            $loaders[] = new DiscoveryLoader($this->discoveryBasePath, $this->discoveryScanDirs, $this->discoveryExcludeDirs, $discoverer);
         }
 
         foreach ($loaders as $loader) {
@@ -537,4 +548,15 @@ public function build(): Server
 
         return new Server($protocol, $logger);
     }
+
+    private function createDiscoverer(LoggerInterface $logger): DiscovererInterface
+    {
+        $discoverer = new \Mcp\Capability\Discovery\Discoverer($logger, null, $this->schemaGenerator);
+
+        if (null !== $this->discoveryCache) {
+            return new \Mcp\Capability\Discovery\CachedDiscoverer($discoverer, $this->discoveryCache, $logger);
+        }
+
+        return $discoverer;
+    }
 }