Reworking database connection checking and adding a test script.

MySQL PDO extension throws an error instead of an exception when trying to query from a connection that has gone away, it fucked everything up. Hopefully the other PDO extensions don't do the same.
Also added the ability to manually check the connection and force reconnect yourself.

autoloader.php

@@ -0,0 +1,21 @@
+<?php
+spl_autoload_register(
+	function ($className)
+	{
+		$ds = DIRECTORY_SEPARATOR;
+		$className = str_replace('js\\tools\\dbhandler', '', $className);
+		$className = str_replace('\\', $ds, $className);
+		$className = trim($className, $ds);
+
+		$path = __DIR__ . $ds . 'src' . $ds . $className . '.php';
+
+		if (!is_readable($path))
+		{
+			return false;
+		}
+
+		require $path;
+		return true;
+	},
+	true
+);

src/Handler.php

@@ -33,13 +33,16 @@ public static function getConnection($name = 'default', array $connectionParamet
 			throw new DbException('Invalid connection name ' . var_export($name, true));
 		}
 
-		/** @var Handler[] */
+		/** @var Handler[] $connections */
 		static $connections = [];
 
 		if (isset($connections[$name]))
 		{
 			// existing connection, check if it is valid and if not - try to reconnect
-			$connections[$name]->checkConnection();
+			if (!$connections[$name]->checkConnection())
+			{
+				$connections[$name]->connect();
+			}
 		}
 		else
 		{
@@ -82,9 +85,10 @@ private function __construct($name, $connectionParameters, $customOptions)
 		$options = array_merge($defaultOptions, $customOptions);
 
 		$this->name = $name;
-		$this->connection = self::connect($connectionParameters, $options);
 		$this->connectionParameters = $connectionParameters;
 		$this->connectionOptions = $options;
+
+		$this->connect();
 	}
 
 	private function __clone()
@@ -286,36 +290,49 @@ public function getLastInsertId()
 		return $this->connection->lastInsertId();
 	}
 
-	private function checkConnection()
+	public function checkConnection()
 	{
 		try
 		{
-			$sum = $this->connection->query('SELECT 1 + 1')->fetchColumn(0);
+			// this throws an error (not an exception) if the connection has gone away;
+			// needs to be suppressed because we want only exceptions
+			$sum = @$this->connection->query('SELECT 1 + 1');
+
+			if ($sum instanceof \PDOStatement)
+			{
+				$sum = $sum->fetchColumn(0);
+			}
+			else
+			{
+				$sum = 0;
+			}
 
 			if (intval($sum) !== 2)
 			{
-				// Invalid result, try reconnecting because something is clearly wrong.
-				$this->connection = self::connect($this->connectionParameters, $this->connectionOptions);
+				// Invalid result, something is clearly wrong.
+				return false;
 			}
 		}
 		catch (\Exception $e)
 		{
-			// Connection may have timed out, try reconnecting.
+			// Connection may have timed out.
 			// There is no single standard SQLSTATE code for "connection timed out", nor is there a built-in way to check this,
 			// so we can only guess that that's what happened.
-			$this->connection = self::connect($this->connectionParameters, $this->connectionOptions);
+			return false;
 		}
+
+		return true;
 	}
 
-	private static function connect($connectionParameters, $connectionOptions)
+	public function connect()
 	{
 		try
 		{
-			return new \PDO(
-				self::buildDNSString($connectionParameters),
-				$connectionParameters['username'],
-				$connectionParameters['password'],
-				$connectionOptions
+			$this->connection = new \PDO(
+				self::buildDNSString($this->connectionParameters),
+				$this->connectionParameters['username'],
+				$this->connectionParameters['password'],
+				$this->connectionOptions
 			);
 		}
 		catch (\PDOException $e)

test.php

@@ -1,28 +1,6 @@
 <?php
-// composer code:
-// require __DIR__ . '/vendor/autoload.php';
-// non-composer code (can run this in console immediately):
-spl_autoload_register(
-	function ($className)
-	{
-		$ds = DIRECTORY_SEPARATOR;
-		$className = str_replace('js\\tools\\dbhandler', '', $className);
-		$className = str_replace('\\', $ds, $className);
-		$className = trim($className, $ds);
-
-		$path = __DIR__ . $ds . 'src' . $ds . $className . '.php';
-
-		if (!is_readable($path))
-		{
-			return false;
-		}
-
-		require $path;
-		return true;
-	},
-	true
-);
-// common code:
+require 'autoloader.php';
+
 use js\tools\dbhandler\exceptions\DbException;
 use js\tools\dbhandler\exceptions\QueryException;
 use js\tools\dbhandler\Handler;

test_mysql_timeout.php

@@ -0,0 +1,46 @@
+<?php
+require 'autoloader.php';
+
+use js\tools\dbhandler\exceptions\DbException;
+use js\tools\dbhandler\Handler;
+
+try
+{
+	// TODO set your own test connection parameters!
+	$handler = Handler::getConnection('test', [
+		'driver' => 'mysql',
+		'username' => 'test',
+		'password' => 'test',
+		'database' => 'test',
+	]);
+	// this is the mysql.ini variable that should be adjusted according to needs
+	// but it works via query as well
+	$handler->exec('SET SESSION wait_timeout = 1');
+
+	echo 'connection timeout set to 1 second, sleeping', PHP_EOL;
+	sleep(3);
+
+	if ($handler->checkConnection())
+	{
+		echo 'connection is good', PHP_EOL;
+	}
+	else
+	{
+		echo 'connection is down, reconnecting', PHP_EOL;
+		$handler->connect();
+	}
+
+	if ($handler->checkConnection())
+	{
+		echo 'connection is now good', PHP_EOL;
+	}
+	else
+	{
+		echo 'connection is still down, failed to reconnect', PHP_EOL;
+	}
+}
+catch (DbException $e)
+{
+	echo $e->getMessage(), PHP_EOL;
+	die();
+}