Implement GetServerInfo Handler with Routing Validation Fix and Full Testkit Integration

src/Basic/Driver.php

@@ -16,6 +16,7 @@
 use Laudis\Neo4j\Contracts\AuthenticateInterface;
 use Laudis\Neo4j\Contracts\DriverInterface;
 use Laudis\Neo4j\Databags\DriverConfiguration;
+use Laudis\Neo4j\Databags\ServerInfo;
 use Laudis\Neo4j\Databags\SessionConfiguration;
 use Laudis\Neo4j\DriverFactory;
 use Laudis\Neo4j\Formatter\SummarizedResultFormatter;
@@ -44,6 +45,11 @@ public function verifyConnectivity(?SessionConfiguration $config = null): bool
         return $this->driver->verifyConnectivity($config);
     }
 
+    public function getServerInfo(?SessionConfiguration $config = null): ServerInfo
+    {
+        return $this->driver->getServerInfo($config);
+    }
+
     public static function create(string|UriInterface $uri, ?DriverConfiguration $configuration = null, ?AuthenticateInterface $authenticate = null): self
     {
         $driver = DriverFactory::create($uri, $configuration, $authenticate, SummarizedResultFormatter::create());

src/Bolt/BoltConnection.php

@@ -65,6 +65,11 @@ class BoltConnection implements ConnectionInterface
      */
     private array $subscribedResults = [];
     private bool $inTransaction = false;
+    /** @var array<string, bool> Track if this connection was ever used for a query */
+    private array $connectionUsed = [
+        'reader' => false,
+        'writer' => false,
+    ];
 
     /**
      * @return array{0: V4_4|V5|V5_1|V5_2|V5_3|V5_4|null, 1: Connection}
@@ -199,13 +204,6 @@ public function reset(): void
         $this->subscribedResults = [];
     }
 
-    private function prepareForBegin(): void
-    {
-        if (in_array($this->getServerState(), ['STREAMING', 'TX_STREAMING'], true)) {
-            $this->discardUnconsumedResults();
-        }
-    }
-
     /**
      * Begins a transaction.
      *
@@ -254,6 +252,12 @@ public function run(
         ?AccessMode $mode,
         ?iterable $tsxMetadata,
     ): array {
+        if ($mode === AccessMode::WRITE()) {
+            $this->connectionUsed['writer'] = true;
+        } else {
+            $this->connectionUsed['reader'] = true;
+        }
+
         if ($this->isInTransaction()) {
             $extra = [];
         } else {
@@ -321,17 +325,17 @@ public function __destruct()
 
     public function close(): void
     {
-        try {
-            if ($this->isOpen()) {
-                if ($this->isStreaming()) {
-                    $this->discardUnconsumedResults();
-                }
+        if ($this->isOpen()) {
+            if ($this->isStreaming() && (($this->connectionUsed['reader'] ?? false) || ($this->connectionUsed['writer'] ?? false))) {
+                $this->discardUnconsumedResults();
+            }
+
+            if (($this->connectionUsed['reader'] ?? false) || ($this->connectionUsed['writer'] ?? false)) {
                 $message = $this->messageFactory->createGoodbyeMessage();
                 $message->send();
-
-                unset($this->boltProtocol); // has to be set to null as the sockets don't recover nicely contrary to what the underlying code might lead you to believe;
             }
-        } catch (Throwable) {
+
+            unset($this->boltProtocol);
         }
     }
 
@@ -437,6 +441,7 @@ public function assertNoFailure(Response $response): void
     public function discardUnconsumedResults(): void
     {
         $this->logger?->log(LogLevel::DEBUG, 'Discarding unconsumed results');
+
         $this->subscribedResults = array_values(array_filter(
             $this->subscribedResults,
             static fn (WeakReference $ref): bool => $ref->get() !== null
@@ -451,6 +456,13 @@ public function discardUnconsumedResults(): void
         $state = $this->getServerState();
         $this->logger?->log(LogLevel::DEBUG, "Server state before discard: {$state}");
 
+        if (!($this->connectionUsed['reader'] ?? false) && !($this->connectionUsed['writer'] ?? false)) {
+            $this->logger?->log(LogLevel::DEBUG, 'Skipping discard - connection never used');
+            $this->subscribedResults = [];
+
+            return;
+        }
+
         try {
             if (in_array($state, ['STREAMING', 'TX_STREAMING'], true)) {
                 $this->discard(null);

src/Bolt/BoltDriver.php

@@ -25,7 +25,9 @@
 use Laudis\Neo4j\Contracts\DriverInterface;
 use Laudis\Neo4j\Contracts\SessionInterface;
 use Laudis\Neo4j\Databags\DriverConfiguration;
+use Laudis\Neo4j\Databags\ServerInfo;
 use Laudis\Neo4j\Databags\SessionConfiguration;
+use Laudis\Neo4j\Enum\AccessMode;
 use Laudis\Neo4j\Formatter\SummarizedResultFormatter;
 use Psr\Http\Message\UriInterface;
 use Psr\Log\LogLevel;
@@ -97,6 +99,37 @@ public function verifyConnectivity(?SessionConfiguration $config = null): bool
         return true;
     }
 
+    /**
+     * Gets server information without running a query.
+     *
+     * Acquires a connection from the pool and extracts server metadata.
+     * The pool handles all connection management, routing, and retries.
+     *
+     * @throws Exception if unable to acquire a connection
+     */
+    public function getServerInfo(?SessionConfiguration $config = null): ServerInfo
+    {
+        $config ??= SessionConfiguration::default()->withAccessMode(AccessMode::READ());
+
+        $connectionGenerator = $this->pool->acquire($config);
+        /**
+         * @var BoltConnection $connection
+         *
+         * @psalm-suppress UnnecessaryVarAnnotation
+         */
+        $connection = GeneratorHelper::getReturnFromGenerator($connectionGenerator);
+
+        try {
+            return new ServerInfo(
+                $connection->getServerAddress(),
+                $connection->getProtocol(),
+                $connection->getServerAgent()
+            );
+        } finally {
+            $this->pool->release($connection);
+        }
+    }
+
     public function closeConnections(): void
     {
         $this->pool->close();

src/Bolt/Session.php

@@ -172,8 +172,6 @@ private function acquireConnection(TransactionConfiguration $config, SessionConf
          */
         $connection = GeneratorHelper::getReturnFromGenerator($connectionGenerator);
 
-        // We try and let the server do the timeout management.
-        // Since the client should not run indefinitely, we just add the client side by two, just in case
         $timeout = $config->getTimeout();
         if ($timeout !== null) {
             $timeout = ($timeout < 30) ? 30 : $timeout;

src/Contracts/DriverInterface.php

@@ -13,6 +13,7 @@
 
 namespace Laudis\Neo4j\Contracts;
 
+use Laudis\Neo4j\Databags\ServerInfo;
 use Laudis\Neo4j\Databags\SessionConfiguration;
 use Laudis\Neo4j\Types\CypherList;
 use Laudis\Neo4j\Types\CypherMap;
@@ -35,6 +36,14 @@ public function createSession(?SessionConfiguration $config = null): SessionInte
      */
     public function verifyConnectivity(?SessionConfiguration $config = null): bool;
 
+    /**
+     * Gets server information without running a query.
+     *
+     * Acquires a connection from the pool and extracts server metadata.
+     * The pool handles all connection management, routing, and retries.
+     */
+    public function getServerInfo(?SessionConfiguration $config = null): ServerInfo;
+
     /**
      * Closes all connections in the pool.
      */

src/Databags/SessionConfiguration.php

@@ -41,9 +41,27 @@ public function __construct(
         private readonly ?AccessMode $accessMode = null,
         private readonly ?array $bookmarks = null,
         private readonly ?Neo4jLogger $logger = null,
+        private readonly ?string $impersonatedUser = null,
     ) {
     }
 
+    public function withImpersonatedUser(?string $user): self
+    {
+        return new self(
+            $this->database,
+            $this->fetchSize,
+            $this->accessMode,
+            $this->bookmarks,
+            $this->logger,
+            $user
+        );
+    }
+
+    public function getImpersonatedUser(): ?string
+    {
+        return $this->impersonatedUser;
+    }
+
     /**
      * @pure
      *

src/Neo4j/Neo4jConnectionPool.php

@@ -193,6 +193,10 @@ private function getNextServer(RoutingTable $table, AccessMode $mode): Uri
             $servers = $table->getWithRole(RoutingRoles::FOLLOWER());
         }
 
+        if (empty($servers)) {
+            throw new RuntimeException('No available servers found for the requested access mode');
+        }
+
         return Uri::create($servers[random_int(0, count($servers) - 1)]);
     }
 
@@ -259,6 +263,16 @@ public function close(): void
         $this->cache->clear();
     }
 
+    /**
+     * Forces a routing table refresh for the given configuration.
+     * This will cause the next acquire() call to fetch a fresh routing table.
+     */
+    public function refreshRoutingTable(SessionConfiguration $config): void
+    {
+        $key = $this->createKey($this->data, $config);
+        $this->cache->delete($key);
+    }
+
     /**
      * @return Generator<string>
      */

src/Neo4j/Neo4jDriver.php

@@ -19,6 +19,7 @@
 use function is_string;
 
 use Laudis\Neo4j\Authentication\Authenticate;
+use Laudis\Neo4j\Bolt\BoltConnection;
 use Laudis\Neo4j\Bolt\Session;
 use Laudis\Neo4j\Common\DNSAddressResolver;
 use Laudis\Neo4j\Common\GeneratorHelper;
@@ -28,7 +29,9 @@
 use Laudis\Neo4j\Contracts\DriverInterface;
 use Laudis\Neo4j\Contracts\SessionInterface;
 use Laudis\Neo4j\Databags\DriverConfiguration;
+use Laudis\Neo4j\Databags\ServerInfo;
 use Laudis\Neo4j\Databags\SessionConfiguration;
+use Laudis\Neo4j\Enum\AccessMode;
 use Laudis\Neo4j\Formatter\SummarizedResultFormatter;
 use Psr\Http\Message\UriInterface;
 use Psr\Log\LogLevel;
@@ -75,6 +78,8 @@ public static function create(string|UriInterface $uri, ?DriverConfiguration $co
     /**
      * @psalm-mutation-free
      *
+     * @psalm-suppress UnnecessaryVarAnnotation
+     *
      * @throws Exception
      */
     public function createSession(?SessionConfiguration $config = null): SessionInterface
@@ -99,6 +104,39 @@ public function verifyConnectivity(?SessionConfiguration $config = null): bool
         return true;
     }
 
+    /**
+     * Gets server information without running a query.
+     *
+     * Acquires a connection from the pool and extracts server metadata.
+     * The pool handles all connection management, routing, and retries.
+     *
+     * @throws Exception if unable to acquire a connection
+     */
+    public function getServerInfo(?SessionConfiguration $config = null): ServerInfo
+    {
+        $config ??= SessionConfiguration::default()->withAccessMode(AccessMode::READ());
+
+        $this->pool->refreshRoutingTable($config);
+
+        $connectionGenerator = $this->pool->acquire($config);
+        /**
+         * @var BoltConnection $connection
+         *
+         * @psalm-suppress UnnecessaryVarAnnotation
+         */
+        $connection = GeneratorHelper::getReturnFromGenerator($connectionGenerator);
+
+        try {
+            return new ServerInfo(
+                $connection->getServerAddress(),
+                $connection->getProtocol(),
+                $connection->getServerAgent()
+            );
+        } finally {
+            $this->pool->release($connection);
+        }
+    }
+
     public function closeConnections(): void
     {
         $this->pool->close();

testkit-backend/src/Handlers/DriverClose.php

@@ -35,6 +35,8 @@ public function __construct(MainRepository $repository)
      */
     public function handle($request): DriverResponse
     {
+        $driver = $this->repository->getDriver($request->getDriverId());
+        $driver->closeConnections();
         $this->repository->removeDriver($request->getDriverId());
 
         return new DriverResponse($request->getDriverId());