19 files changed, 2106 insertions, 0 deletions
diff --git a/phpBB/install/exception/cannot_build_container_exception.php b/phpBB/install/exception/cannot_build_container_exception.php
new file mode 100644
index 0000000000..11be507bc9
--- /dev/null
+++ b/phpBB/install/exception/cannot_build_container_exception.php
@@ -0,0 +1,22 @@
+<?php
+/**
+ *
+ * This file is part of the phpBB Forum Software package.
+ *
+ * @copyright (c) phpBB Limited <https://www.phpbb.com>
+ * @license GNU General Public License, version 2 (GPL-2.0)
+ *
+ * For full copyright and license information, please see
+ * the docs/CREDITS.txt file.
+ *
+ */
+
+namespace phpbb\install\exception;
+
+/**
+ * This exception should be thrown when
+ */
+class cannot_build_container_exception extends installer_exception
+{
+
+}
diff --git a/phpBB/install/exception/invalid_dbms_exception.php b/phpBB/install/exception/invalid_dbms_exception.php
new file mode 100644
index 0000000000..ccb35bc237
--- /dev/null
+++ b/phpBB/install/exception/invalid_dbms_exception.php
@@ -0,0 +1,22 @@
+<?php
+/**
+ *
+ * This file is part of the phpBB Forum Software package.
+ *
+ * @copyright (c) phpBB Limited <https://www.phpbb.com>
+ * @license GNU General Public License, version 2 (GPL-2.0)
+ *
+ * For full copyright and license information, please see
+ * the docs/CREDITS.txt file.
+ *
+ */
+
+namespace phpbb\install\exception;
+
+/**
+ * This exception should be thrown when
+ */
+class invalid_dbms_exception extends installer_exception
+{
+
+}
diff --git a/phpBB/install/exception/user_interaction_required_exception.php b/phpBB/install/exception/user_interaction_required_exception.php
new file mode 100644
index 0000000000..0aaae648cf
--- /dev/null
+++ b/phpBB/install/exception/user_interaction_required_exception.php
@@ -0,0 +1,22 @@
+<?php
+/**
+ *
+ * This file is part of the phpBB Forum Software package.
+ *
+ * @copyright (c) phpBB Limited <https://www.phpbb.com>
+ * @license GNU General Public License, version 2 (GPL-2.0)
+ *
+ * For full copyright and license information, please see
+ * the docs/CREDITS.txt file.
+ *
+ */
+
+namespace phpbb\install\exception;
+
+/**
+ * This exception should be thrown when user interaction is inevitable
+ */
+class user_interaction_required_exception extends installer_exception
+{
+
+}
diff --git a/phpBB/install/helper/config.php b/phpBB/install/helper/config.php
new file mode 100644
index 0000000000..b759df737e
--- /dev/null
+++ b/phpBB/install/helper/config.php
@@ -0,0 +1,259 @@
+<?php
+/**
+ *
+ * This file is part of the phpBB Forum Software package.
+ *
+ * @copyright (c) phpBB Limited <https://www.phpbb.com>
+ * @license GNU General Public License, version 2 (GPL-2.0)
+ *
+ * For full copyright and license information, please see
+ * the docs/CREDITS.txt file.
+ *
+ */
+
+namespace phpbb\install\helper;
+
+/**
+ * Stores common settings and installation status
+ */
+class config
+{
+	/**
+	 * @var \phpbb\filesystem\filesystem_interface
+	 */
+	protected $filesystem;
+
+	/**
+	 * Array which contains config settings for the installer
+	 *
+	 * The array will also store all the user input, as well as any
+	 * data that is passed to other tasks by a task.
+	 *
+	 * @var array
+	 */
+	protected $installer_config;
+
+	/**
+	 * @var string
+	 */
+	protected $install_config_file;
+
+	/**
+	 * @var \phpbb\php\ini
+	 */
+	protected $php_ini;
+
+	/**
+	 * @var string
+	 */
+	protected $phpbb_root_path;
+
+	/**
+	 * Array containing progress information
+	 *
+	 * @var array
+	 */
+	protected $progress_data;
+
+	/**
+	 * Array containing system information
+	 *
+	 * The array contains run time and memory limitations.
+	 *
+	 * @var array
+	 */
+	protected $system_data;
+
+	/**
+	 * Constructor
+	 */
+	public function __construct(\phpbb\filesystem\filesystem_interface $filesystem, \phpbb\php\ini $php_ini, $phpbb_root_path)
+	{
+		$this->filesystem		= $filesystem;
+		$this->php_ini			= $php_ini;
+		$this->phpbb_root_path	= $phpbb_root_path;
+
+		// Set up data arrays
+		$this->installer_config	= array();
+		$this->system_data		= array();
+		$this->progress_data	= array(
+			'last_task_module_index'	=> 0,
+			'last_task_module_name'		=> '', // Stores the service name of the latest finished module
+			'last_task_index'			=> 0,
+			'last_task_name'			=> '', // Stores the service name of the latest finished task
+		);
+
+		$this->install_config_file = $this->phpbb_root_path . 'store/install_config.php';
+
+		$this->setup_system_data();
+	}
+
+	/**
+	 * Returns data for a specified parameter
+	 *
+	 * @param	string	$param_name	Name of the parameter to return
+	 * @param	mixed	$default	Default value to return when the specified data
+	 * 								does not exist.
+	 *
+	 * @return 	mixed	value of the specified parameter or the default value if the data
+	 * 					cannot be recovered.
+	 */
+	public function get($param_name, $default = false)
+	{
+		return (isset($this->installer_config[$param_name])) ? $this->installer_config[$param_name] : $default;
+	}
+
+	/**
+	 * Sets a parameter in installer_config
+	 *
+	 * @param	string	$param_name	Name of the parameter
+	 * @param	mixed	$value		Values to set the parameter
+	 *
+	 * @return null
+	 */
+	public function set($param_name, $value)
+	{
+		$this->installer_config = array_merge($this->installer_config, array(
+			$param_name => $value,
+		));
+	}
+
+	/**
+	 * Returns system parameter
+	 *
+	 * @param string	$param_name	Name of the parameter
+	 *
+	 * @return mixed	Returns system parameter if it is defined, false otherwise
+	 */
+	public function system_get($param_name)
+	{
+		return (isset($this->system_data[$param_name])) ? $this->system_data[$param_name] : false;
+	}
+
+	/**
+	 * Returns remaining time until the run time limit
+	 *
+	 * @return int	Remaining time until the run time limit in seconds
+	 */
+	public function get_time_remaining()
+	{
+		return ($this->system_data['start_time'] + $this->system_data['max_execution_time']) - time();
+	}
+
+	/**
+	 * Returns remaining memory available for PHP
+	 *
+	 * @return int	Remaining memory until reaching the limit
+	 */
+	public function get_memory_remaining()
+	{
+		if (function_exists('memory_get_usage'))
+		{
+			return ($this->system_data['memory_limit'] - memory_get_usage());
+		}
+
+		// If we cannot get the information then just return a positive number (and cross fingers)
+		return 1;
+	}
+
+	/**
+	 * Saves the latest executed task
+	 *
+	 * @param string	$task_service_name	Name of the installer task service
+	 * @param int		$task_index			Index of the task in the task list array
+	 *
+	 * @return null
+	 */
+	public function set_finished_task($task_service_name, $task_index)
+	{
+		$this->progress_data['last_task_name']	= $task_service_name;
+		$this->progress_data['last_task_index']	= $task_index;
+	}
+
+	/**
+	 * Set active module
+	 *
+	 * @param string	$module_service_name	Name of the installer module service
+	 * @param int		$module_index			Index of the module in the module list array
+	 *
+	 * @return null
+	 */
+	public function set_active_module($module_service_name, $module_index)
+	{
+		$this->progress_data['last_task_module_name']	= $module_service_name;
+		$this->progress_data['last_task_module_index']	= $module_index;
+	}
+
+	/**
+	 * Getter for progress data
+	 *
+	 * @return array
+	 */
+	public function get_progress_data()
+	{
+		return $this->progress_data;
+	}
+
+	/**
+	 * Recovers install configuration from file
+	 *
+	 * @return null
+	 */
+	public function load_config()
+	{
+		if (!$this->filesystem->exists($this->install_config_file))
+		{
+			return;
+		}
+
+		$file_content = @file_get_contents($this->install_config_file);
+		$serialized_data = trim(substr($file_content, 8));
+		$unserialized_data = unserialize($serialized_data);
+
+		$this->installer_config = $unserialized_data['installer_config'];
+		$this->progress_data = $unserialized_data['progress_data'];
+	}
+
+	/**
+	 * Dumps install configuration to disk
+	 *
+	 * @return null
+	 */
+	public function save_config()
+	{
+		// Create array to save
+		$save_array = array(
+			'installer_config'	=> $this->installer_config,
+			'progress_data'		=> $this->progress_data,
+		);
+
+		// Create file content
+		$file_content = '<?php // ';
+		$file_content .= serialize($save_array);
+		$file_content .= "\n";
+
+		// Dump file_content to disk
+		$fp = fopen($this->install_config_file, 'w');
+		fwrite($fp, $file_content);
+		fclose($fp);
+	}
+
+	/**
+	 * Filling up system_data array
+	 *
+	 * @return null
+	 */
+	protected function setup_system_data()
+	{
+		// Query maximum runtime from php.ini
+		$execution_time = $this->php_ini->get_int('max_execution_time');
+		$execution_time = min(15, $execution_time / 2);
+		$this->system_data['max_execution_time'] = $execution_time;
+
+		// Set start time
+		$this->system_data['start_time'] = time();
+
+		// Get memory limit
+		$this->system_data['memory_limit'] = $this->php_ini->get_bytes('memory_limit');
+	}
+}
diff --git a/phpBB/install/helper/container_factory.php b/phpBB/install/helper/container_factory.php
new file mode 100644
index 0000000000..255f8f428e
--- /dev/null
+++ b/phpBB/install/helper/container_factory.php
@@ -0,0 +1,149 @@
+<?php
+/**
+ *
+ * This file is part of the phpBB Forum Software package.
+ *
+ * @copyright (c) phpBB Limited <https://www.phpbb.com>
+ * @license GNU General Public License, version 2 (GPL-2.0)
+ *
+ * For full copyright and license information, please see
+ * the docs/CREDITS.txt file.
+ *
+ */
+
+namespace phpbb\install\helper;
+
+use phpbb\install\exception\cannot_build_container_exception;
+
+class container_factory
+{
+	/**
+	 * @var string
+	 */
+	protected $phpbb_root_path;
+
+	/**
+	 * @var string
+	 */
+	protected $php_ext;
+
+	/**
+	 * @var \phpbb\request\request
+	 */
+	protected $request;
+
+	/**
+	 * The full phpBB container
+	 *
+	 * @var \Symfony\Component\DependencyInjection\ContainerInterface
+	 */
+	protected $container;
+
+	/**
+	 * Constructor
+	 *
+	 * @param \phpbb\request\request	$request			Request interface
+	 * @param string					$phpbb_root_path	Path to phpBB's root
+	 * @param string					$php_ext			Extension of PHP files
+	 */
+	public function __construct(\phpbb\request\request $request, $phpbb_root_path, $php_ext)
+	{
+		$this->request			= $request;
+		$this->phpbb_root_path	= $phpbb_root_path;
+		$this->php_ext			= $php_ext;
+		$this->container		= null;
+	}
+
+	/**
+	 * Container getter
+	 *
+	 * @param null|string	$service_name	Name of the service to return
+	 *
+	 * @return \Symfony\Component\DependencyInjection\ContainerInterface|Object	phpBB's dependency injection container
+	 * 																			or the service specified in $service_name
+	 *
+	 * @throws \phpbb\install\exception\cannot_build_container_exception							When container cannot be built
+	 * @throws \Symfony\Component\DependencyInjection\Exception\InvalidArgumentException			If the service is not defined
+	 * @throws \Symfony\Component\DependencyInjection\Exception\ServiceCircularReferenceException	When a circular reference is detected
+	 * @throws \Symfony\Component\DependencyInjection\Exception\ServiceNotFoundException			When the service is not defined
+	 */
+	public function get($service_name = null)
+	{
+		// Check if container was built, if not try to build it
+		if ($this->container === null)
+		{
+			// Check whether container can be built
+			// We need config.php for that so let's check if it has been set up yet
+			if (filesize($this->phpbb_root_path . 'config.' . $this->php_ext))
+			{
+				$this->build_container();
+			}
+			else
+			{
+				throw new cannot_build_container_exception();
+			}
+		}
+
+		return ($service_name === null) ? $this->container : $this->container->get($service_name);
+	}
+
+	/**
+	 * Returns the specified parameter from the container
+	 *
+	 * @param string	$param_name
+	 *
+	 * @return mixed
+	 */
+	public function get_parameter($param_name)
+	{
+		return $this->container->getParameter($param_name);
+	}
+
+	/**
+	 * Build dependency injection container
+	 */
+	protected function build_container()
+	{
+		// If the container has been already built just return.
+		// Although this should never happen
+		if ($this->container instanceof \Symfony\Component\DependencyInjection\ContainerInterface)
+		{
+			return;
+		}
+
+		$phpbb_config_php_file = new \phpbb\config_php_file($this->phpbb_root_path, $this->php_ext);
+		$phpbb_container_builder = new \phpbb\di\container_builder($this->phpbb_root_path, $this->php_ext);
+
+		// For BC with functions that we need during install
+		global $phpbb_container;
+
+		$disable_super_globals = $this->request->super_globals_disabled();
+
+		// This is needed because container_builder::get_env_parameters() uses $_SERVER
+		if ($disable_super_globals)
+		{
+			$this->request->enable_super_globals();
+		}
+
+		$this->container = $phpbb_container = $phpbb_container_builder
+			->with_config($phpbb_config_php_file)
+			->without_cache()
+			->without_compiled_container()
+			->get_container();
+
+		// Setting request is required for the compatibility globals as those are generated from
+		// this container
+		$this->container->register('request')->setSynthetic(true);
+		$this->container->set('request', $this->request);
+		$this->container->compile();
+
+		// Restore super globals to previous state
+		if ($disable_super_globals)
+		{
+			$this->request->disable_super_globals();
+		}
+
+		// Get compatibilty globals
+		require ($this->phpbb_root_path . 'includes/compatibility_globals.' . $this->php_ext);
+	}
+}
diff --git a/phpBB/install/helper/database.php b/phpBB/install/helper/database.php
new file mode 100644
index 0000000000..d728c8b93b
--- /dev/null
+++ b/phpBB/install/helper/database.php
@@ -0,0 +1,459 @@
+<?php
+/**
+ *
+ * This file is part of the phpBB Forum Software package.
+ *
+ * @copyright (c) phpBB Limited <https://www.phpbb.com>
+ * @license GNU General Public License, version 2 (GPL-2.0)
+ *
+ * For full copyright and license information, please see
+ * the docs/CREDITS.txt file.
+ *
+ */
+
+namespace phpbb\install\helper;
+
+use phpbb\install\exception\invalid_dbms_exception;
+
+/**
+ * Database related general functionality for installer
+ */
+class database
+{
+	/**
+	 * @var \phpbb\filesystem\filesystem_interface
+	 */
+	protected $filesystem;
+
+	/**
+	 * @var string
+	 */
+	protected $phpbb_root_path;
+
+	/**
+	 * @var array
+	 */
+	protected $supported_dbms;
+
+	/**
+	 * Constructor
+	 *
+	 * @param \phpbb\filesystem\filesystem_interface	$filesystem			Filesystem interface
+	 * @param string									$phpbb_root_path	Path to phpBB's root
+	 */
+	public function __construct(\phpbb\filesystem\filesystem_interface $filesystem, $phpbb_root_path)
+	{
+		$this->filesystem = $filesystem;
+
+		// DBMS supported by phpBB
+		$this->supported_dbms = array(
+			// Note: php 5.5 alpha 2 deprecated mysql.
+			// Keep mysqli before mysql in this list.
+			'mysqli'	=> array(
+				'LABEL'			=> 'MySQL with MySQLi Extension',
+				'SCHEMA'		=> 'mysql_41',
+				'MODULE'		=> 'mysqli',
+				'DELIM'			=> ';',
+				'DRIVER'		=> 'phpbb\db\driver\mysqli',
+				'AVAILABLE'		=> true,
+				'2.0.x'			=> true,
+			),
+			'mysql'		=> array(
+				'LABEL'			=> 'MySQL',
+				'SCHEMA'		=> 'mysql',
+				'MODULE'		=> 'mysql',
+				'DELIM'			=> ';',
+				'DRIVER'		=> 'phpbb\db\driver\mysql',
+				'AVAILABLE'		=> true,
+				'2.0.x'			=> true,
+			),
+			'mssql'		=> array(
+				'LABEL'			=> 'MS SQL Server 2000+',
+				'SCHEMA'		=> 'mssql',
+				'MODULE'		=> 'mssql',
+				'DELIM'			=> 'GO',
+				'DRIVER'		=> 'phpbb\db\driver\mssql',
+				'AVAILABLE'		=> true,
+				'2.0.x'			=> true,
+			),
+			'mssql_odbc'=>	array(
+				'LABEL'			=> 'MS SQL Server [ ODBC ]',
+				'SCHEMA'		=> 'mssql',
+				'MODULE'		=> 'odbc',
+				'DELIM'			=> 'GO',
+				'DRIVER'		=> 'phpbb\db\driver\mssql_odbc',
+				'AVAILABLE'		=> true,
+				'2.0.x'			=> true,
+			),
+			'mssqlnative'		=> array(
+				'LABEL'			=> 'MS SQL Server 2005+ [ Native ]',
+				'SCHEMA'		=> 'mssql',
+				'MODULE'		=> 'sqlsrv',
+				'DELIM'			=> 'GO',
+				'DRIVER'		=> 'phpbb\db\driver\mssqlnative',
+				'AVAILABLE'		=> true,
+				'2.0.x'			=> false,
+			),
+			'oracle'	=>	array(
+				'LABEL'			=> 'Oracle',
+				'SCHEMA'		=> 'oracle',
+				'MODULE'		=> 'oci8',
+				'DELIM'			=> '/',
+				'DRIVER'		=> 'phpbb\db\driver\oracle',
+				'AVAILABLE'		=> true,
+				'2.0.x'			=> false,
+			),
+			'postgres' => array(
+				'LABEL'			=> 'PostgreSQL 8.3+',
+				'SCHEMA'		=> 'postgres',
+				'MODULE'		=> 'pgsql',
+				'DELIM'			=> ';',
+				'DRIVER'		=> 'phpbb\db\driver\postgres',
+				'AVAILABLE'		=> true,
+				'2.0.x'			=> true,
+			),
+			'sqlite'		=> array(
+				'LABEL'			=> 'SQLite',
+				'SCHEMA'		=> 'sqlite',
+				'MODULE'		=> 'sqlite',
+				'DELIM'			=> ';',
+				'DRIVER'		=> 'phpbb\db\driver\sqlite',
+				'AVAILABLE'		=> true,
+				'2.0.x'			=> false,
+			),
+			'sqlite3'		=> array(
+				'LABEL'			=> 'SQLite3',
+				'SCHEMA'		=> 'sqlite',
+				'MODULE'		=> 'sqlite3',
+				'DELIM'			=> ';',
+				'DRIVER'		=> 'phpbb\db\driver\sqlite3',
+				'AVAILABLE'		=> true,
+				'2.0.x'			=> false,
+			),
+		);
+	}
+
+	/**
+	 * Returns an array of available DBMS supported by phpBB
+	 *
+	 * If a DBMS is specified it will only return data for that DBMS
+	 * and will load its extension if necessary.
+	 *
+	 * @param	mixed	$dbms				name of the DBMS that's info is required or false for all DBMS info
+	 * @param	bool	$return_unavailable	set it to true if you expect unavailable but supported DBMS
+	 * 										returned as well
+	 * @param	bool	$only_20x_options	set it to true if you only want to recover 2.0.x options
+	 *
+	 * @return	array	Array of available and supported DBMS
+	 */
+	public function get_available_dbms($dbms = false, $return_unavailable = false, $only_20x_options = false)
+	{
+		$available_dbms = $this->supported_dbms;
+
+		if ($dbms)
+		{
+			if (isset($this->supported_dbms[$dbms]))
+			{
+				$available_dbms = array($dbms => $this->supported_dbms[$dbms]);
+			}
+			else
+			{
+				return array();
+			}
+		}
+
+		$any_dbms_available = false;
+		foreach ($available_dbms as $db_name => $db_array)
+		{
+			if ($only_20x_options && !$db_array['2.0.x'])
+			{
+				if ($return_unavailable)
+				{
+					$available_dbms[$db_name]['AVAILABLE'] = false;
+				}
+				else
+				{
+					unset($available_dbms[$db_name]);
+				}
+
+				continue;
+			}
+
+			$dll = $db_array['MODULE'];
+			if (!@extension_loaded($dll))
+			{
+				if ($return_unavailable)
+				{
+					$available_dbms[$db_name]['AVAILABLE'] = false;
+				}
+				else
+				{
+					unset($available_dbms[$db_name]);
+				}
+
+				continue;
+			}
+
+			$any_dbms_available = true;
+		}
+
+		if ($return_unavailable)
+		{
+			$available_dbms['ANY_DB_SUPPORT'] = $any_dbms_available;
+		}
+
+		return $available_dbms;
+	}
+
+	/**
+	 * Removes "/* style" as well as "# style" comments from $input.
+	 *
+	 * @param string $sql_query	Input string
+	 *
+	 * @return string Input string with comments removed
+	 */
+	public function remove_comments($sql_query)
+	{
+		// Remove /* */ comments (http://ostermiller.org/findcomment.html)
+		$sql_query = preg_replace('#/\*(.|[\r\n])*?\*/#', "\n", $sql_query);
+
+		// Remove # style comments
+		$sql_query = preg_replace('/\n{2,}/', "\n", preg_replace('/^#.*$/m', "\n", $sql_query));
+
+		return $sql_query;
+	}
+
+	/**
+	 * split_sql_file() will split an uploaded sql file into single sql statements.
+	 *
+	 * Note: expects trim() to have already been run on $sql.
+	 *
+	 * @param	string	$sql		SQL statements
+	 * @param	string	$delimiter	Delimiter between sql statements
+	 *
+	 * @return array Array of sql statements
+	 */
+	public function split_sql_file($sql, $delimiter)
+	{
+		$sql = str_replace("\r" , '', $sql);
+		$data = preg_split('/' . preg_quote($delimiter, '/') . '$/m', $sql);
+
+		$data = array_map('trim', $data);
+
+		// The empty case
+		$end_data = end($data);
+
+		if (empty($end_data))
+		{
+			unset($data[key($data)]);
+		}
+
+		return $data;
+	}
+
+	/**
+	 * Validates table prefix
+	 *
+	 * @param string	$dbms			The selected dbms
+	 * @param string	$table_prefix	The table prefix to validate
+	 *
+	 * @return bool|array	true if table prefix is valid, array of errors otherwise
+	 *
+	 * @throws \phpbb\install\exception\invalid_dbms_exception When $dbms is not a valid
+	 */
+	public function validate_table_prefix($dbms, $table_prefix)
+	{
+		$errors = array();
+
+		if (!preg_match('#^[a-zA-Z][a-zA-Z0-9_]*$#', $table_prefix))
+		{
+			$errors[] = array(
+				'title' => 'INST_ERR_DB_INVALID_PREFIX',
+			);
+		}
+
+		// Do dbms specific checks
+		$dbms_info = $this->get_available_dbms($dbms);
+		switch ($dbms_info[$dbms]['SCHEMA'])
+		{
+			case 'mysql':
+			case 'mysql_41':
+				$prefix_length = 36;
+			break;
+			case 'mssql':
+				$prefix_length = 90;
+			break;
+			case 'oracle':
+				$prefix_length = 6;
+			break;
+			case 'postgres':
+				$prefix_length = 36;
+			break;
+			case 'sqlite':
+				$prefix_length = 200;
+			break;
+			default:
+				throw new invalid_dbms_exception();
+			break;
+		}
+
+		// Check the prefix length to ensure that index names are not too long
+		if (strlen($table_prefix) > $prefix_length)
+		{
+			$errors[] = array(
+				'title' => array('INST_ERR_PREFIX_TOO_LONG', $prefix_length),
+			);
+		}
+
+		return (empty($errors)) ? true : $errors;
+	}
+
+	/**
+	 * Check if the user provided database parameters are correct
+	 *
+	 * This function checks the database connection data and also checks for
+	 * any other problems that could cause an error during the installation
+	 * such as if there is any database table names conflicting.
+	 *
+	 * Note: The function assumes that $table_prefix has been already validated
+	 * with validate_table_prefix().
+	 *
+	 * @param string	$dbms			Selected database type
+	 * @param string	$dbhost			Database host address
+	 * @param int		$dbport			Database port number
+	 * @param string	$dbuser			Database username
+	 * @param string	$dbpass			Database password
+	 * @param string	$dbname			Database name
+	 * @param string	$table_prefix	Database table prefix
+	 *
+	 * @return array|bool	Returns true if test is successful, array of errors otherwise
+	 */
+	public function check_database_connection($dbms, $dbhost, $dbport, $dbuser, $dbpass, $dbname, $table_prefix)
+	{
+		$dbms_info = $this->get_available_dbms($dbms);
+		$dbms_info = $dbms_info[$dbms];
+		$errors = array();
+
+		// Instantiate it and set return on error true
+		/** @var \phpbb\db\driver\driver_interface $db */
+		$db = new $dbms_info['DRIVER'];
+		$db->sql_return_on_error(true);
+
+		// Check that we actually have a database name before going any further
+		if (!in_array($dbms_info['SCHEMA'], array('sqlite', 'oracle')) && $dbname === '')
+		{
+			$errors[] = array(
+				'title' => 'INST_ERR_DB_NO_NAME',
+			);
+		}
+
+		// Make sure we don't have a daft user who thinks having the SQLite database in the forum directory is a good idea
+		if ($dbms_info['SCHEMA'] === 'sqlite'
+			&& stripos($this->filesystem->realpath($dbhost), $this->filesystem->realpath($this->phpbb_root_path) === 0))
+		{
+			$errors[] = array(
+				'title' =>'INST_ERR_DB_FORUM_PATH',
+			);
+		}
+
+		// Try to connect to db
+		if (is_array($db->sql_connect($dbhost, $dbuser, $dbpass, $dbname, $dbport, false, true)))
+		{
+			$db_error = $db->sql_error();
+			$errors[] = array(
+				'title' => 'INST_ERR_DB_CONNECT',
+				'description' => ($db_error['message']) ? utf8_convert_message($db_error['message']) : 'INST_ERR_DB_NO_ERROR',
+			);
+		}
+		else
+		{
+			// Check if there is any table name collisions
+			$temp_prefix = strtolower($table_prefix);
+			$table_ary = array(
+				$temp_prefix . 'attachments',
+				$temp_prefix . 'config',
+				$temp_prefix . 'sessions',
+				$temp_prefix . 'topics',
+				$temp_prefix . 'users',
+			);
+
+			$db_tools_factory = new \phpbb\db\tools\factory();
+			$db_tools = $db_tools_factory->get($db);
+			$tables = $db_tools->sql_list_tables();
+			$tables = array_map('strtolower', $tables);
+			$table_intersect = array_intersect($tables, $table_ary);
+
+			if (sizeof($table_intersect))
+			{
+				$errors[] = array(
+					'title' => 'INST_ERR_PREFIX',
+				);
+			}
+
+			// Check if database version is supported
+			switch ($dbms)
+			{
+				case 'mysqli':
+					if (version_compare(mysqli_get_server_info($db->get_db_connect_id()), '4.1.3', '<'))
+					{
+						$errors[] = array(
+							'title' => 'INST_ERR_DB_NO_MYSQLI',
+						);
+					}
+				break;
+				case 'sqlite':
+					if (version_compare(sqlite_libversion(), '2.8.2', '<'))
+					{
+						$errors[] = array(
+							'title' => 'INST_ERR_DB_NO_SQLITE',
+						);
+					}
+				break;
+				case 'sqlite3':
+					$version = \SQLite3::version();
+					if (version_compare($version['versionString'], '3.6.15', '<'))
+					{
+						$errors[] = array(
+							'title' => 'INST_ERR_DB_NO_SQLITE3',
+						);
+					}
+				break;
+				case 'oracle':
+					$sql = "SELECT *
+						FROM NLS_DATABASE_PARAMETERS
+						WHERE PARAMETER = 'NLS_RDBMS_VERSION'
+							OR PARAMETER = 'NLS_CHARACTERSET'";
+					$result = $db->sql_query($sql);
+
+					while ($row = $db->sql_fetchrow($result))
+					{
+						$stats[$row['parameter']] = $row['value'];
+					}
+					$db->sql_freeresult($result);
+
+					if (version_compare($stats['NLS_RDBMS_VERSION'], '9.2', '<') && $stats['NLS_CHARACTERSET'] !== 'UTF8')
+					{
+						$errors[] = array(
+							'title' => 'INST_ERR_DB_NO_ORACLE',
+						);
+					}
+				break;
+				case 'postgres':
+					$sql = "SHOW server_encoding;";
+					$result = $db->sql_query($sql);
+					$row = $db->sql_fetchrow($result);
+					$db->sql_freeresult($result);
+
+					if ($row['server_encoding'] !== 'UNICODE' && $row['server_encoding'] !== 'UTF8')
+					{
+						$errors[] = array(
+							'title' => 'INST_ERR_DB_NO_POSTGRES',
+						);
+					}
+				break;
+			}
+		}
+
+		return (empty($errors)) ? true : $errors;
+	}
+}
diff --git a/phpBB/install/helper/iohandler/ajax_iohandler.php b/phpBB/install/helper/iohandler/ajax_iohandler.php
new file mode 100644
index 0000000000..44a185139e
--- /dev/null
+++ b/phpBB/install/helper/iohandler/ajax_iohandler.php
@@ -0,0 +1,202 @@
+<?php
+/**
+ *
+ * This file is part of the phpBB Forum Software package.
+ *
+ * @copyright (c) phpBB Limited <https://www.phpbb.com>
+ * @license GNU General Public License, version 2 (GPL-2.0)
+ *
+ * For full copyright and license information, please see
+ * the docs/CREDITS.txt file.
+ *
+ */
+
+namespace phpbb\install\helper\iohandler;
+
+/**
+ * Input-Output handler for the AJAX frontend
+ */
+class ajax_iohandler extends iohandler_base
+{
+	/**
+	 * @var \phpbb\request\request_interface
+	 */
+	protected $request;
+
+	/**
+	 * @var \phpbb\template\template
+	 */
+	protected $template;
+
+	/**
+	 * @var string
+	 */
+	protected $form;
+
+	/**
+	 * Constructor
+	 *
+	 * @param \phpbb\request\request_interface	$request	HTTP request interface
+	 * @param \phpbb\template\template			$template	Template engine
+	 */
+	public function __construct(\phpbb\request\request_interface $request, \phpbb\template\template $template)
+	{
+		$this->request	= $request;
+		$this->template	= $template;
+		$this->form		= '';
+
+		parent::__construct();
+	}
+
+	/**
+	 * {@inheritdoc}
+	 */
+	public function get_input($name, $default, $multibyte = false)
+	{
+		return $this->request->variable($name, $default, $multibyte);
+	}
+
+	/**
+	 * {@inheritdoc}
+	 */
+	public function get_server_variable($name, $default = '')
+	{
+		return $this->request->server($name, $default);
+	}
+
+	/**
+	 * {@inheritdoc}
+	 */
+	public function get_header_variable($name, $default = '')
+	{
+		return $this->request->header($name, $default);
+	}
+
+	/**
+	 * {@inheritdoc}
+	 */
+	public function is_secure()
+	{
+		return $this->request->is_secure();
+	}
+
+	/**
+	 * {@inheritdoc}
+	 */
+	public function add_user_form_group($title, $form)
+	{
+		//
+		// This code is pretty ugly... but works
+		//
+
+		$this->template->assign_block_vars('options', array(
+			'LEGEND'	=> $this->language->lang($title),
+			'S_LEGEND'	=> true,
+		));
+
+		foreach ($form as $input_name => $input_options)
+		{
+			if (!isset($input_options['type']))
+			{
+				continue;
+			}
+
+			$tpl_ary = array();
+
+			$tpl_ary['TYPE'] = $input_options['type'];
+			$tpl_ary['TITLE'] = $this->language->lang($input_options['label']);
+			$tpl_ary['KEY'] = $input_name;
+			$tpl_ary['S_EXPLAIN'] = false;
+
+			if (isset($input_options['default']))
+			{
+				$default = $input_options['default'];
+				$default = preg_replace_callback('#\{L_([A-Z0-9\-_]*)\}#s', array($this, 'lang_replace_callback'), $default);
+				$tpl_ary['DEFAULT'] = $default;
+			}
+
+			if (isset($input_options['description']))
+			{
+				$tpl_ary['TITLE_EXPLAIN'] = $this->language->lang($input_options['description']);
+				$tpl_ary['S_EXPLAIN'] = true;
+			}
+
+			if (in_array($input_options['type'], array('select', 'radio')))
+			{
+				for ($i = 0, $total = sizeof($input_options['options']); $i < $total; $i++)
+				{
+					if (isset($input_options['options'][$i]['label']))
+					{
+						$input_options['options'][$i]['label'] = $this->language->lang($input_options['options'][$i]['label']);
+					}
+				}
+
+				$tpl_ary['OPTIONS'] = $input_options['options'];
+			}
+
+			$this->template->assign_block_vars('options', $tpl_ary);
+		}
+
+		$this->template->set_filenames(array(
+			'form_install' => 'installer_form.html',
+		));
+
+		$this->form = $this->template->assign_display('form_install');
+	}
+
+	/**
+	 * {@inheritdoc}
+	 */
+	public function send_response()
+	{
+		$json_data_array = $this->prepare_json_array();
+		$json_data = json_encode($json_data_array);
+
+		// Try to push content to the browser
+		print (str_pad(' ', 4096) . "\n");
+		print ($json_data . "\n\n");
+		flush();
+	}
+
+	/**
+	 * Prepares iohandler's data to be sent out to the client.
+	 *
+	 * @return array
+	 */
+	protected function prepare_json_array()
+	{
+		$json_array = array(
+			'errors' => $this->errors,
+			'warnings' => $this->warnings,
+			'logs' => $this->logs,
+		);
+
+		if (!empty($this->form))
+		{
+			$json_array['form'] = $this->form;
+			$this->form = '';
+		}
+
+		$this->errors = array();
+		$this->warnings = array();
+		$this->logs = array();
+
+		return $json_array;
+	}
+
+	/**
+	 * Callback function for language replacing
+	 *
+	 * @param array	$matches
+	 * @return string
+	 */
+	public function lang_replace_callback($matches)
+	{
+		if (!empty($matches[1]))
+		{
+			return $this->language->lang($matches[1]);
+		}
+
+		return '';
+	}
+}
diff --git a/phpBB/install/helper/iohandler/exception/iohandler_not_implemented_exception.php b/phpBB/install/helper/iohandler/exception/iohandler_not_implemented_exception.php
new file mode 100644
index 0000000000..f2ddeda6f7
--- /dev/null
+++ b/phpBB/install/helper/iohandler/exception/iohandler_not_implemented_exception.php
@@ -0,0 +1,19 @@
+<?php
+/**
+ *
+ * This file is part of the phpBB Forum Software package.
+ *
+ * @copyright (c) phpBB Limited <https://www.phpbb.com>
+ * @license GNU General Public License, version 2 (GPL-2.0)
+ *
+ * For full copyright and license information, please see
+ * the docs/CREDITS.txt file.
+ *
+ */
+
+namespace phpbb\install\helper\iohandler\exception;
+
+class iohandler_not_implemented_exception extends \Exception
+{
+
+}
diff --git a/phpBB/install/helper/iohandler/factory.php b/phpBB/install/helper/iohandler/factory.php
new file mode 100644
index 0000000000..0b59e5ec63
--- /dev/null
+++ b/phpBB/install/helper/iohandler/factory.php
@@ -0,0 +1,72 @@
+<?php
+/**
+ *
+ * This file is part of the phpBB Forum Software package.
+ *
+ * @copyright (c) phpBB Limited <https://www.phpbb.com>
+ * @license GNU General Public License, version 2 (GPL-2.0)
+ *
+ * For full copyright and license information, please see
+ * the docs/CREDITS.txt file.
+ *
+ */
+
+namespace phpbb\install\helper\iohandler;
+
+use phpbb\install\helper\iohandler\exception\iohandler_not_implemented_exception;
+
+/**
+ * Input-output handler factory
+ */
+class factory
+{
+	/**
+	 * @var \Symfony\Component\DependencyInjection\ContainerInterface
+	 */
+	protected $container;
+
+	/**
+	 * @var string
+	 */
+	protected $environment;
+
+	/**
+	 * Constructor
+	 *
+	 * @param \Symfony\Component\DependencyInjection\ContainerInterface $container Dependency injection container
+	 */
+	public function __construct(\Symfony\Component\DependencyInjection\ContainerInterface $container)
+	{
+		$this->container	= $container;
+		$this->environment	= null;
+	}
+
+	/**
+	 * @param string	$environment	The name of the input-output handler to use
+	 */
+	public function set_environment($environment)
+	{
+		$this->environment = $environment;
+	}
+
+	/**
+	 * Factory getter for iohandler
+	 *
+	 * @return \phpbb\install\helper\iohandler\iohandler_interface
+	 *
+	 * @throws \phpbb\install\helper\iohandler\exception\iohandler_not_implemented_exception
+	 * 		When the specified iohandler_interface does not exists
+	 */
+	public function get()
+	{
+		switch ($this->environment)
+		{
+			case 'ajax':
+				return $this->container->get('installer.helper.iohandler_ajax');
+			break;
+			default:
+				throw new iohandler_not_implemented_exception();
+			break;
+		}
+	}
+}
diff --git a/phpBB/install/helper/iohandler/iohandler_base.php b/phpBB/install/helper/iohandler/iohandler_base.php
new file mode 100644
index 0000000000..0d5467d202
--- /dev/null
+++ b/phpBB/install/helper/iohandler/iohandler_base.php
@@ -0,0 +1,121 @@
+<?php
+/**
+ *
+ * This file is part of the phpBB Forum Software package.
+ *
+ * @copyright (c) phpBB Limited <https://www.phpbb.com>
+ * @license GNU General Public License, version 2 (GPL-2.0)
+ *
+ * For full copyright and license information, please see
+ * the docs/CREDITS.txt file.
+ *
+ */
+
+namespace phpbb\install\helper\iohandler;
+
+/**
+ * Base class for installer input-output handlers
+ */
+abstract class iohandler_base implements iohandler_interface
+{
+	/**
+	 * Array of errors
+	 *
+	 * Errors should be added, when the installation cannot continue without
+	 * user interaction. If the aim is to notify the user about something, please
+	 * use a warning instead.
+	 *
+	 * @var array
+	 */
+	protected $errors;
+
+	/**
+	 * Array of warnings
+	 *
+	 * @var array
+	 */
+	protected $warnings;
+
+	/**
+	 * Array of logs
+	 *
+	 * @var array
+	 */
+	protected $logs;
+
+	/**
+	 * @var \phpbb\language\language
+	 */
+	protected $language;
+
+	/**
+	 * Constructor
+	 */
+	public function __construct()
+	{
+		$this->errors	= array();
+		$this->warnings	= array();
+		$this->logs		= array();
+	}
+
+	/**
+	 * Set language service
+	 *
+	 * @param \phpbb\language\language $language
+	 *
+	 * @return null
+	 */
+	public function set_language(\phpbb\language\language $language)
+	{
+		$this->language = $language;
+	}
+
+	/**
+	 * {@inheritdoc}
+	 */
+	public function add_error_message($error_title, $error_description = false)
+	{
+		$this->errors[] = $this->translate_message($error_title, $error_description);
+	}
+
+	/**
+	 * {@inheritdoc}
+	 */
+	public function add_warning_message($warning_title, $warning_description = false)
+	{
+		$this->warnings[] = $this->translate_message($warning_title, $warning_description);
+	}
+
+	/**
+	 * {@inheritdoc}
+	 */
+	public function add_log_message($log_title, $log_description = false)
+	{
+		$this->logs[] = $this->translate_message($log_title, $log_description);
+	}
+
+	/**
+	 * Localize message.
+	 *
+	 * Note: When an array is passed into the parameters below, it will be
+	 * resolved as printf($param[0], $param[1], ...).
+	 *
+	 * @param array|string		$title			Title of the message
+	 * @param array|string|bool	$description	Description of the message
+	 *
+	 * @return array	Localized message in an array
+	 */
+	protected function translate_message($title, $description)
+	{
+		$message_array = array();
+
+		$message_array['title'] = call_user_func_array(array($this->language, 'lang'), (array) $title);
+
+		if ($description !== false)
+		{
+			$message_array['description'] = call_user_func_array(array($this->language, 'lang'), (array) $description);
+		}
+
+		return $message_array;
+	}
+}
diff --git a/phpBB/install/helper/iohandler/iohandler_interface.php b/phpBB/install/helper/iohandler/iohandler_interface.php
new file mode 100644
index 0000000000..cea5610586
--- /dev/null
+++ b/phpBB/install/helper/iohandler/iohandler_interface.php
@@ -0,0 +1,119 @@
+<?php
+/**
+ *
+ * This file is part of the phpBB Forum Software package.
+ *
+ * @copyright (c) phpBB Limited <https://www.phpbb.com>
+ * @license GNU General Public License, version 2 (GPL-2.0)
+ *
+ * For full copyright and license information, please see
+ * the docs/CREDITS.txt file.
+ *
+ */
+
+namespace phpbb\install\helper\iohandler;
+
+/**
+ * Input-Output handler interface for the installer
+ */
+interface iohandler_interface
+{
+	/**
+	 * Renders or returns response message
+	 */
+	public function send_response();
+
+	/**
+	 * Returns input variable
+	 *
+	 * @param string	$name		Name of the input variable to obtain
+	 * @param mixed		$default	A default value that is returned if the variable was not set.
+	 * 								This function will always return a value of the same type as the default.
+	 * @param bool		$multibyte	If $default is a string this paramater has to be true if the variable may contain any UTF-8 characters
+	 *								Default is false, causing all bytes outside the ASCII range (0-127) to be replaced with question marks
+	 *
+	 * @return mixed	Value of the input variable
+	 */
+	public function get_input($name, $default, $multibyte = false);
+
+	/**
+	 * Returns server variable
+	 *
+	 * This function should work the same as request_interterface::server().
+	 *
+	 * @param string	$name		Name of the server variable
+	 * @param mixed		$default	Default value to return when the requested variable does not exist
+	 *
+	 * @return mixed	Value of the server variable
+	 */
+	public function get_server_variable($name, $default = '');
+
+	/**
+	 * Wrapper function for request_interterface::header()
+	 *
+	 * @param string	$name		Name of the request header variable
+	 * @param mixed		$default	Default value to return when the requested variable does not exist
+	 *
+	 * @return mixed
+	 */
+	public function get_header_variable($name, $default = '');
+
+	/**
+	 * Returns true if the connection is encrypted
+	 *
+	 * @return bool
+	 */
+	public function is_secure();
+
+	/**
+	 * Adds an error message to the rendering queue
+	 *
+	 * Note: When an array is passed into the parameters below, it will be
+	 * resolved as printf($param[0], $param[1], ...).
+	 *
+	 * @param string|array		$error_title		Title of the error message.
+	 * @param string|bool|array	$error_description	Description of the error (and possibly guidelines to resolve it),
+	 * 												or false if the error description is not available.
+	 *
+	 * @return null
+	 */
+	public function add_error_message($error_title, $error_description = false);
+
+	/**
+	 * Adds a warning message to the rendering queue
+	 *
+	 * Note: When an array is passed into the parameters below, it will be
+	 * resolved as printf($param[0], $param[1], ...).
+	 *
+	 * @param string|array		$warning_title			Title of the error message
+	 * @param string|bool|array	$warning_description	Description of the error (and possibly guidelines to resolve it),
+	 * 													or false if the error description is not available
+	 *
+	 * @return null
+	 */
+	public function add_warning_message($warning_title, $warning_description = false);
+
+	/**
+	 * Adds a log message to the rendering queue
+	 *
+	 * Note: When an array is passed into the parameters below, it will be
+	 * resolved as printf($param[0], $param[1], ...).
+	 *
+	 * @param string|array		$log_title			Title of the error message
+	 * @param string|bool|array	$log_description	Description of the error (and possibly guidelines to resolve it),
+	 * 												or false if the error description is not available
+	 *
+	 * @return null
+	 */
+	public function add_log_message($log_title, $log_description = false);
+
+	/**
+	 * Adds a requested data group to the rendering queue
+	 *
+	 * @param string	$title	Language variable with the title of the form
+	 * @param array		$form	An array describing the required data (options etc)
+	 *
+	 * @return null
+	 */
+	public function add_user_form_group($title, $form);
+}
diff --git a/phpBB/install/helper/navigation/install_navigation.php b/phpBB/install/helper/navigation/install_navigation.php
new file mode 100644
index 0000000000..3e29e55038
--- /dev/null
+++ b/phpBB/install/helper/navigation/install_navigation.php
@@ -0,0 +1,28 @@
+<?php
+/**
+ *
+ * This file is part of the phpBB Forum Software package.
+ *
+ * @copyright (c) phpBB Limited <https://www.phpbb.com>
+ * @license GNU General Public License, version 2 (GPL-2.0)
+ *
+ * For full copyright and license information, please see
+ * the docs/CREDITS.txt file.
+ *
+ */
+
+namespace phpbb\install\helper\navigation;
+
+class install_navigation implements navigation_interface
+{
+	public function get()
+	{
+		return array(
+			'install'	=> array(
+				'label'	=> 'INSTALL',
+				'route'	=> 'phpbb_installer_install',
+				'order'	=> 0,
+			),
+		);
+	}
+}
diff --git a/phpBB/install/helper/navigation/navigation_interface.php b/phpBB/install/helper/navigation/navigation_interface.php
new file mode 100644
index 0000000000..eebdbe923f
--- /dev/null
+++ b/phpBB/install/helper/navigation/navigation_interface.php
@@ -0,0 +1,43 @@
+<?php
+/**
+ *
+ * This file is part of the phpBB Forum Software package.
+ *
+ * @copyright (c) phpBB Limited <https://www.phpbb.com>
+ * @license GNU General Public License, version 2 (GPL-2.0)
+ *
+ * For full copyright and license information, please see
+ * the docs/CREDITS.txt file.
+ *
+ */
+
+namespace phpbb\install\helper\navigation;
+
+/**
+ * Interface for installer's navigation defining services
+ */
+interface navigation_interface
+{
+	/**
+	 * Returns an array with the navigation items
+	 *
+	 * The returned array should have the following format:
+	 * <code>
+	 * array(
+	 * 	'parent_nav_name' => array(
+	 * 		'nav_name' => array(
+	 * 			'label' => 'MY_MENU',
+	 * 			'route' => 'phpbb_route_name',
+	 * 		)
+	 * 	)
+	 * )
+	 * </code>
+	 *
+	 * Navigation item setting options:
+	 * 	- label: The language variable name
+	 * 	- route: Name of the route which it is belongs to
+	 *
+	 * @return array
+	 */
+	public function get();
+}
diff --git a/phpBB/install/helper/navigation/navigation_provider.php b/phpBB/install/helper/navigation/navigation_provider.php
new file mode 100644
index 0000000000..ddb2509348
--- /dev/null
+++ b/phpBB/install/helper/navigation/navigation_provider.php
@@ -0,0 +1,92 @@
+<?php
+/**
+ *
+ * This file is part of the phpBB Forum Software package.
+ *
+ * @copyright (c) phpBB Limited <https://www.phpbb.com>
+ * @license GNU General Public License, version 2 (GPL-2.0)
+ *
+ * For full copyright and license information, please see
+ * the docs/CREDITS.txt file.
+ *
+ */
+
+namespace phpbb\install\helper\navigation;
+
+/**
+ * Installers navigation provider
+ */
+class navigation_provider
+{
+	/**
+	 * @var array
+	 */
+	private $menu_collection;
+
+	/**
+	 * Constructor
+	 *
+	 * @param \phpbb\di\service_collection                              $plugins
+	 */
+	public function __construct(\phpbb\di\service_collection $plugins)
+	{
+		$this->menu_collection	= array();
+
+		foreach ($plugins as $plugin => $plugin_instance)
+		{
+			$this->register($plugin_instance);
+		}
+	}
+
+	/**
+	 * Returns navigation array
+	 *
+	 * @return array
+	 */
+	public function get()
+	{
+		return $this->menu_collection;
+	}
+
+	/**
+	 * Registers a navigation provider's navigation items
+	 *
+	 * @param navigation_interface	$navigation
+	 */
+	public function register(navigation_interface $navigation)
+	{
+		$nav_arry = $navigation->get();
+		$this->merge($nav_arry, $this->menu_collection);
+	}
+
+	/**
+	 * Recursive array merge
+	 *
+	 * This function is necessary to be able to replace the options of
+	 * already set navigation items.
+	 *
+	 * @param array	$array_to_merge
+	 * @param array	$array_to_merge_into
+	 */
+	private function merge(&$array_to_merge, &$array_to_merge_into)
+	{
+		foreach ($array_to_merge as $key => $value)
+		{
+			if (isset($array_to_merge_into[$key]))
+			{
+				if (is_array($array_to_merge_into[$key]) && is_array($value))
+				{
+					$this->merge($value, $array_to_merge_into[$key]);
+				}
+				else
+				{
+					$array_to_merge_into[$key] = $value;
+				}
+			}
+			else
+			{
+				$array_to_merge_into[$key] = $value;
+			}
+		}
+	}
+}
diff --git a/phpBB/install/installer.php b/phpBB/install/installer.php
new file mode 100644
index 0000000000..5a2fcc4d85
--- /dev/null
+++ b/phpBB/install/installer.php
@@ -0,0 +1,146 @@
+<?php
+/**
+ *
+ * This file is part of the phpBB Forum Software package.
+ *
+ * @copyright (c) phpBB Limited <https://www.phpbb.com>
+ * @license GNU General Public License, version 2 (GPL-2.0)
+ *
+ * For full copyright and license information, please see
+ * the docs/CREDITS.txt file.
+ *
+ */
+
+namespace phpbb\install;
+
+class installer
+{
+	/**
+	 * @var \Symfony\Component\DependencyInjection\ContainerInterface
+	 */
+	protected $container;
+
+	/**
+	 * @var \phpbb\install\helper\config
+	 */
+	protected $install_config;
+
+	/**
+	 * @var array
+	 */
+	protected $installer_modules;
+
+	/**
+	 * Constructor
+	 *
+	 * @param \phpbb\install\helper\config	$config		Installer config handler
+	 * @param \Symfony\Component\DependencyInjection\ContainerInterface	$container	Dependency injection container
+	 */
+	public function __construct(\phpbb\install\helper\config $config, \Symfony\Component\DependencyInjection\ContainerInterface $container)
+	{
+		$this->install_config		= $config;
+		$this->container			= $container;
+		$this->installer_modules	= array();
+	}
+
+	/**
+	 * Sets modules to execute
+	 *
+	 * Note: The installer will run modules in the order they are set in
+	 * the array.
+	 *
+	 * @param array	$modules	Array of module service names
+	 */
+	public function set_modules($modules)
+	{
+		$modules = (array) $modules;
+
+		$this->installer_modules = $modules;
+	}
+
+	/**
+	 * Run phpBB installer
+	 *
+	 * @return null
+	 */
+	public function run()
+	{
+		// Load install progress
+		$this->install_config->load_config();
+
+		// Recover install progress
+		$module_index = $this->recover_progress();
+
+		$install_finished = false;
+
+		try
+		{
+			// Run until there are available resources
+			while ($this->install_config->get_time_remaining() > 0 && $this->install_config->get_memory_remaining() > 0)
+			{
+				// Check if module exists, if not the install is completed
+				if (!isset($this->installer_modules[$module_index]))
+				{
+					$install_finished = true;
+					break;
+				}
+
+				// Log progress
+				$module_service_name = $this->installer_modules[$module_index];
+				$this->install_config->set_active_module($module_service_name, $module_index);
+
+				// Get module from container
+				/** @var \phpbb\install\module_interface $module */
+				$module = $this->container->get($module_service_name);
+
+				$module_index++;
+
+				// Check if module should be executed
+				if (!$module->is_essential() && !$module->check_requirements())
+				{
+					continue;
+				}
+
+				$module->run();
+
+				// Clear task progress
+				$this->install_config->set_finished_task('', 0);
+			}
+
+			if ($install_finished)
+			{
+				die ("install finished");
+			}
+			else
+			{
+				die ("install memory or time limit reached");
+			}
+		}
+		catch (\phpbb\install\exception\user_interaction_required_exception $e)
+		{
+			// @todo handle exception
+		}
+
+		// Save install progress
+		$this->install_config->save_config();
+	}
+
+	/**
+	 * Recover install progress
+	 *
+	 * @return int	Index of the next installer module to execute
+	 */
+	protected function recover_progress()
+	{
+		$progress_array = $this->install_config->get_progress_data();
+		$module_service = $progress_array['last_task_module_name'];
+		$module_index = $progress_array['last_task_module_index'];
+
+		if ($this->installer_modules[$module_index] === $module_service)
+		{
+			return $module_index;
+		}
+
+		return 0;
+	}
+}
diff --git a/phpBB/install/module_base.php b/phpBB/install/module_base.php
new file mode 100644
index 0000000000..defccaefef
--- /dev/null
+++ b/phpBB/install/module_base.php
@@ -0,0 +1,175 @@
+<?php
+/**
+ *
+ * This file is part of the phpBB Forum Software package.
+ *
+ * @copyright (c) phpBB Limited <https://www.phpbb.com>
+ * @license GNU General Public License, version 2 (GPL-2.0)
+ *
+ * For full copyright and license information, please see
+ * the docs/CREDITS.txt file.
+ *
+ */
+
+namespace phpbb\install;
+
+/**
+ * Base class for installer module
+ */
+abstract class module_base implements module_interface
+{
+	/**
+	 * @var \Symfony\Component\DependencyInjection\ContainerInterface
+	 */
+	protected $container;
+
+	/**
+	 * @var \phpbb\install\helper\config
+	 */
+	protected $install_config;
+
+	/**
+	 * @var \phpbb\install\helper\iohandler\iohandler_interface
+	 */
+	protected $iohandler;
+
+	/**
+	 * @var bool
+	 */
+	protected $is_essential;
+
+	/**
+	 * Array of tasks for installer module
+	 *
+	 * @var array
+	 */
+	protected $task_collection;
+
+	/**
+	 * Installer module constructor
+	 *
+	 * @param array	$tasks		array of installer tasks for installer module
+	 * @param bool	$essential	flag that indicates if module is essential or not
+	 */
+	public function __construct(array $tasks, $essential = true)
+	{
+		$this->task_collection	= $tasks;
+		$this->is_essential		= $essential;
+	}
+
+	/**
+	 * Dependency getter
+	 *
+	 * @param \Symfony\Component\DependencyInjection\ContainerInterface	$container
+	 * @param \phpbb\install\helper\config								$config
+	 * @param \phpbb\install\helper\iohandler\iohandler_interface		$iohandler
+	 *
+	 * @return null
+	 */
+	public function setup(\Symfony\Component\DependencyInjection\ContainerInterface $container, \phpbb\install\helper\config $config, \phpbb\install\helper\iohandler\iohandler_interface $iohandler)
+	{
+		$this->container		= $container;
+		$this->install_config	= $config;
+		$this->iohandler		= $iohandler;
+	}
+
+	/**
+	 * {@inheritdoc}
+	 */
+	public function is_essential()
+	{
+		return $this->is_essential;
+	}
+
+	/**
+	 * {@inheritdoc}
+	 *
+	 * Overwrite this method if your task is non-essential!
+	 */
+	public function check_requirements()
+	{
+		return true;
+	}
+
+	/**
+	 * {@inheritdoc}
+	 */
+	public function run()
+	{
+		// Recover install progress
+		$task_index = $this->recover_progress();
+
+		// Run until there are available resources
+		while ($this->install_config->get_time_remaining() > 0 && $this->install_config->get_memory_remaining() > 0)
+		{
+			// Check if task exists
+			if (!isset($this->task_collection[$task_index]))
+			{
+				break;
+			}
+
+			// Recover task to be executed
+			/** @var \phpbb\install\task_interface $task */
+			$task = $this->container->get($this->task_collection[$task_index]);
+
+			// Iterate to the next task
+			$task_index++;
+
+			// Check if we can run the task
+			if (!$task->is_essential() && !$task->check_requirements())
+			{
+				continue;
+			}
+
+			$task->run();
+
+			// Increment progress
+			if ($this->get_task_count() !== 0)
+			{
+				//$this->iohandler->increment_progress();
+			}
+
+			$this->iohandler->send_response();
+
+			// Log install progress
+			$current_task_index = $task_index - 1;
+			$this->install_config->set_finished_task($this->task_collection[$current_task_index], $current_task_index);
+		}
+	}
+
+	/**
+	 * Returns the next task's index
+	 *
+	 * @return int	index of the array element of the next task
+	 */
+	protected function recover_progress()
+	{
+		$progress_array = $this->install_config->get_progress_data();
+		$last_finished_task_name = $progress_array['last_task_name'];
+		$last_finished_task_index = $progress_array['last_task_index'];
+
+		// Check if the data is relevant to this module
+		if (isset($this->task_collection[$last_finished_task_index]))
+		{
+			if ($this->task_collection[$last_finished_task_index] === $last_finished_task_name)
+			{
+				// Return the task index of the next task
+				return $last_finished_task_index + 1;
+			}
+		}
+
+		// As of now if the progress has not been resolved we assume that it is because
+		// the task progress belongs to the previous module,
+		// so just default to the first task
+		// @todo make module aware of it's service name that way this can be improved
+		return 0;
+	}
+
+	/**
+	 * {@inheritdoc}
+	 */
+	public function get_task_count()
+	{
+		return sizeof($this->task_collection);
+	}
+}
diff --git a/phpBB/install/module_interface.php b/phpBB/install/module_interface.php
new file mode 100644
index 0000000000..e0ec4e4347
--- /dev/null
+++ b/phpBB/install/module_interface.php
@@ -0,0 +1,56 @@
+<?php
+/**
+ *
+ * This file is part of the phpBB Forum Software package.
+ *
+ * @copyright (c) phpBB Limited <https://www.phpbb.com>
+ * @license GNU General Public License, version 2 (GPL-2.0)
+ *
+ * For full copyright and license information, please see
+ * the docs/CREDITS.txt file.
+ *
+ */
+
+namespace phpbb\install;
+
+/**
+ * Interface for installer modules
+ *
+ * An installer module is a task collection which executes installer tasks.
+ */
+interface module_interface
+{
+	/**
+	 * Checks if the execution of the module is essential to install phpBB or it can be skipped
+	 *
+	 * Note: Please note that all the non-essential modules have to implement check_requirements()
+	 * method.
+	 *
+	 * @return	bool	true if the module is essential, false otherwise
+	 */
+	public function is_essential();
+
+	/**
+	 * Checks requirements for the tasks
+	 *
+	 * Note: Only need to be implemented for non-essential tasks, as essential tasks
+	 * requirements should be checked in the requirements install module.
+	 *
+	 * @return bool	true if the task's requirements are met
+	 */
+	public function check_requirements();
+
+	/**
+	 * Executes the task
+	 *
+	 * @return	null
+	 */
+	public function run();
+
+	/**
+	 * Returns the number of tasks in the module
+	 *
+	 * @return int
+	 */
+	public function get_task_count();
+}
diff --git a/phpBB/install/task_base.php b/phpBB/install/task_base.php
new file mode 100644
index 0000000000..5946be8c52
--- /dev/null
+++ b/phpBB/install/task_base.php
@@ -0,0 +1,53 @@
+<?php
+/**
+ *
+ * This file is part of the phpBB Forum Software package.
+ *
+ * @copyright (c) phpBB Limited <https://www.phpbb.com>
+ * @license GNU General Public License, version 2 (GPL-2.0)
+ *
+ * For full copyright and license information, please see
+ * the docs/CREDITS.txt file.
+ *
+ */
+
+namespace phpbb\install;
+
+/**
+ * Base class for installer task
+ */
+abstract class task_base implements task_interface
+{
+	/**
+	 * @var bool
+	 */
+	protected $is_essential;
+
+	/**
+	 * Constructor
+	 *
+	 * @param bool $essential
+	 */
+	public function __construct($essential = true)
+	{
+		$this->is_essential = $essential;
+	}
+
+	/**
+	 * {@inheritdoc}
+	 */
+	public function is_essential()
+	{
+		return $this->is_essential;
+	}
+
+	/**
+	 * {@inheritdoc}
+	 *
+	 * Overwrite this method if your task is non-essential!
+	 */
+	public function check_requirements()
+	{
+		return true;
+	}
+}
diff --git a/phpBB/install/task_interface.php b/phpBB/install/task_interface.php
new file mode 100644
index 0000000000..9cfc4d19c2
--- /dev/null
+++ b/phpBB/install/task_interface.php
@@ -0,0 +1,47 @@
+<?php
+/**
+ *
+ * This file is part of the phpBB Forum Software package.
+ *
+ * @copyright (c) phpBB Limited <https://www.phpbb.com>
+ * @license GNU General Public License, version 2 (GPL-2.0)
+ *
+ * For full copyright and license information, please see
+ * the docs/CREDITS.txt file.
+ *
+ */
+
+namespace phpbb\install;
+
+/**
+ * Interface for installer tasks
+ */
+interface task_interface
+{
+	/**
+	 * Checks if the task is essential to install phpBB or it can be skipped
+	 *
+	 * Note: Please note that all the non-essential modules have to implement check_requirements()
+	 * method.
+	 *
+	 * @return	bool	true if the task is essential, false otherwise
+	 */
+	public function is_essential();
+
+	/**
+	 * Checks requirements for the tasks
+	 *
+	 * Note: Only need to be implemented for non-essential tasks, as essential tasks
+	 * requirements should be checked in the requirements install module.
+	 *
+	 * @return bool	true if the task's requirements are met
+	 */
+	public function check_requirements();
+
+	/**
+	 * Executes the task
+	 *
+	 * @return null
+	 */
+	public function run();
+}