ElggInstaller.php

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<?php

use Elgg\Application;
use Elgg\Config;
use Elgg\Database;
use Elgg\Database\DbConfig;
use Elgg\Exceptions\ConfigurationException;
use Elgg\Exceptions\Configuration\InstallationException;
use Elgg\Exceptions\Configuration\RegistrationException;
use Elgg\Exceptions\DatabaseException;
use Elgg\Exceptions\LoginException;
use Elgg\Exceptions\PluginException;
use Elgg\Http\Request;
use Elgg\Project\Paths;
use Elgg\Router\RewriteTester;

class ElggInstaller {
    
    public const MARIADB_MINIMAL_VERSION = '10.3';
    public const MYSQL_MINIMAL_VERSION = '5.7';
    public const PHP_MINIMAL_VERSION = '8.0.0';
    
    private $steps = [
        'welcome',
        'requirements',
        'database',
        'settings',
        'admin',
        'complete',
    ];

    private $has_completed = [
        'config' => false,
        'database' => false,
        'settings' => false,
        'admin' => false,
    ];

    private $is_action = false;

    private $autoLogin = true;

    private $app;

    public function run() {
        $app = $this->getApp();

        $this->is_action = $app->internal_services->request->getMethod() === 'POST';

        $step = $this->getCurrentStep();

        $this->determineInstallStatus();

        $response = $this->checkInstallCompletion($step);
        if ($response) {
            return $response;
        }

        // check if this is an install being resumed
        $response = $this->resumeInstall($step);
        if ($response) {
            return $response;
        }

        $this->finishBootstrapping($step);

        $params = $app->internal_services->request->request->all();

        $method = 'run' . ucwords($step);

        return $this->$method($params);
    }

    protected function getApp() {
        if ($this->app) {
            return $this->app;
        }

        try {
            $config = new Config();
            $config->installer_running = true;
            $config->dbencoding = 'utf8mb4';
            $config->boot_cache_ttl = 0;
            $config->system_cache_enabled = false;
            $config->simplecache_enabled = false;
            $config->debug = \Psr\Log\LogLevel::WARNING;
            $config->cacheroot = Paths::sanitize(sys_get_temp_dir()) . 'elgginstaller/caches/';
            $config->assetroot = Paths::sanitize(sys_get_temp_dir()) . 'elgginstaller/assets/';

            $app = Application::factory([
                'config' => $config,
                'handle_exceptions' => false,
                'handle_shutdown' => false,
            ]);

            // Don't set global $CONFIG, because loading the settings file may require it to write to
            // it, and it can have array sets (e.g. cookie config) that fail when using a proxy for
            // the config service.
            //$app->setGlobalConfig();

            Application::setInstance($app);
            $app->loadCore();
            $this->app = $app;

            $app->internal_services->boot->getCache()->disable();
            $app->internal_services->plugins->getCache()->disable();
            $app->internal_services->sessionCache->disable();
            $app->internal_services->dataCache->disable();
            $app->internal_services->autoloadManager->getCache()->disable();

            $current_step = $this->getCurrentStep();
            $index_admin = array_search('admin', $this->getSteps());
            $index_complete = array_search('complete', $this->getSteps());
            $index_step = array_search($current_step, $this->getSteps());
            
            // For the admin creation action and the complete step we use the Elgg core session handling.
            // Otherwise, use default php session handling
            $use_elgg_session = ($index_step == $index_admin) || ($index_step == $index_complete);
            if (!$use_elgg_session) {
                $session = \ElggSession::fromFiles($app->internal_services->config);
                $session->setName('Elgg_install');
                $app->internal_services->set('session', $session);
            }

            $app->internal_services->views->setViewtype('installation');
            $app->internal_services->views->registerViewtypeFallback('installation');
            $app->internal_services->views->registerPluginViews(Paths::elgg());
            $app->internal_services->translator->registerTranslations(Paths::elgg() . 'install/languages/', true);

            return $this->app;
        } catch (ConfigurationException $ex) {
            throw new InstallationException($ex->getMessage());
        }
    }

    public function setAutoLogin($flag) {
        $this->autoLogin = (bool) $flag;
    }

    public function batchInstall(array $params, $create_htaccess = false) {
        $app = $this->getApp();

        $defaults = [
            'dbhost' => 'localhost',
            'dbport' => '3306',
            'dbprefix' => 'elgg_',
            'language' => 'en',
            'siteaccess' => ACCESS_PUBLIC,
        ];
        $params = array_merge($defaults, $params);

        $required_params = [
            'dbuser',
            'dbpassword',
            'dbname',
            'sitename',
            'wwwroot',
            'dataroot',
            'displayname',
            'email',
            'username',
            'password',
        ];
        foreach ($required_params as $key) {
            if (empty($params[$key])) {
                throw new InstallationException(elgg_echo('install:error:requiredfield', [$key]));
            }
        }

        // password is passed in once
        $params['password1'] = $params['password'];
        $params['password2'] = $params['password'];

        if ($create_htaccess) {
            $rewrite_tester = new RewriteTester();
            if (!$rewrite_tester->createHtaccess($params['wwwroot'])) {
                throw new InstallationException(elgg_echo('install:error:htaccess'));
            }
        }
        
        if (!\Elgg\Http\Urls::isValidMultiByteUrl($params['wwwroot'])) {
            throw new InstallationException(elgg_echo('install:error:wwwroot', [$params['wwwroot']]));
        }

        // sanitize dataroot path
        $params['dataroot'] = Paths::sanitize($params['dataroot']);

        $this->determineInstallStatus();

        if (!$this->has_completed['config']) {
            if (!$this->createSettingsFile($params)) {
                throw new InstallationException(elgg_echo('install:error:settings'));
            }
        }

        $this->loadSettingsFile();

        // Make sure settings file matches parameters
        $config = $app->internal_services->config;
        $config_keys = [
            // param key => config key
            'dbhost' => 'dbhost',
            'dbport' => 'dbport',
            'dbuser' => 'dbuser',
            'dbpassword' => 'dbpass',
            'dbname' => 'dbname',
            'dataroot' => 'dataroot',
            'dbprefix' => 'dbprefix',
        ];
        foreach ($config_keys as $params_key => $config_key) {
            if ($params[$params_key] !== $config->$config_key) {
                throw new InstallationException(elgg_echo('install:error:settings_mismatch', [$config_key, $params[$params_key], $config->$config_key]));
            }
        }

        if (!$this->connectToDatabase()) {
            throw new InstallationException(elgg_echo('install:error:databasesettings'));
        }

        if (!$this->has_completed['database']) {
            if (!$this->installDatabase()) {
                throw new InstallationException(elgg_echo('install:error:cannotloadtables'));
            }
        }

        // load remaining core libraries
        $this->finishBootstrapping('settings');

        if (!$this->saveSiteSettings($params)) {
            throw new InstallationException(elgg_echo('install:error:savesitesettings'));
        }

        if (!$this->createAdminAccount($params)) {
            throw new InstallationException(elgg_echo('install:admin:cannot_create'));
        }
    }

    protected function render($step, $vars = []) {
        $vars['next_step'] = $this->getNextStep($step);

        $title = elgg_echo("install:{$step}");
        $body = elgg_view("install/pages/{$step}", $vars);

        $output = elgg_view_page(
            $title,
            $body,
            'default',
            [
                'step' => $step,
                'steps' => $this->getSteps(),
            ]
        );

        return new \Elgg\Http\OkResponse($output);
    }

    protected function runWelcome($vars) {
        return $this->render('welcome');
    }

    protected function runRequirements($vars) {

        $report = [];

        // check PHP parameters and libraries
        $this->checkPHP($report);

        // check URL rewriting
        $this->checkRewriteRules($report);

        // check for existence of settings file
        if ($this->checkSettingsFile($report) !== true) {
            // no file, so check permissions on engine directory
            $this->isInstallDirWritable($report);
        }

        // check the database later
        $report['database'] = [
            [
                'severity' => 'notice',
                'message' => elgg_echo('install:check:database'),
            ]
        ];

        // any failures?
        $numFailures = $this->countNumConditions($report, 'error');

        // any warnings
        $numWarnings = $this->countNumConditions($report, 'warning');


        $params = [
            'report' => $report,
            'num_failures' => $numFailures,
            'num_warnings' => $numWarnings,
        ];

        return $this->render('requirements', $params);
    }

    protected function runDatabase($submissionVars) {

        $app = $this->getApp();

        $formVars = [
            'dbuser' => [
                'type' => 'text',
                'value' => '',
                'required' => true,
            ],
            'dbpassword' => [
                'type' => 'password',
                'value' => '',
                'required' => false,
            ],
            'dbname' => [
                'type' => 'text',
                'value' => '',
                'required' => true,
            ],
            'dbhost' => [
                'type' => 'text',
                'value' => 'localhost',
                'required' => true,
            ],
            'dbport' => [
                'type' => 'number',
                'value' => 3306,
                'required' => true,
                'min' => 0,
                'max' => 65535,
            ],
            'dbprefix' => [
                'type' => 'text',
                'value' => 'elgg_',
                'required' => false,
            ],
            'dataroot' => [
                'type' => 'text',
                'value' => '',
                'required' => true,
            ],
            'wwwroot' => [
                'type' => 'url',
                'value' => $app->internal_services->config->wwwroot,
                'required' => true,
            ],
            'timezone' => [
                'type' => 'dropdown',
                'value' => 'UTC',
                'options' => \DateTimeZone::listIdentifiers(),
                'required' => true
            ]
        ];

        if ($this->checkSettingsFile()) {
            // user manually created settings file so we fake out action test
            $this->is_action = true;
        }

        if ($this->is_action) {
            $getResponse = function () use ($app, $submissionVars, $formVars) {
                // only create settings file if it doesn't exist
                if (!$this->checkSettingsFile()) {
                    if (!$this->validateDatabaseVars($submissionVars, $formVars)) {
                        // error so we break out of action and serve same page
                        return;
                    }

                    if (!$this->createSettingsFile($submissionVars)) {
                        return;
                    }
                }

                // check db version and connect
                if (!$this->connectToDatabase()) {
                    return;
                }

                if (!$this->installDatabase()) {
                    return;
                }

                $app->internal_services->system_messages->addSuccessMessage(elgg_echo('install:success:database'));

                return $this->continueToNextStep('database');
            };

            $response = $getResponse();
            if ($response) {
                return $response;
            }
        }

        $formVars = $this->makeFormSticky($formVars, $submissionVars);

        $params = ['variables' => $formVars,];

        if ($this->checkSettingsFile()) {
            // settings file exists and we're here so failed to create database
            $params['failure'] = true;
        }

        return $this->render('database', $params);
    }

    protected function runSettings($submissionVars) {

        $app = $this->getApp();

        $formVars = [
            'sitename' => [
                'type' => 'text',
                'value' => 'My New Community',
                'required' => true,
            ],
            'siteemail' => [
                'type' => 'email',
                'value' => '',
                'required' => false,
            ],
            'siteaccess' => [
                'type' => 'access',
                'value' => ACCESS_PUBLIC,
                'required' => true,
            ],
        ];

        if ($this->is_action) {
            $getResponse = function () use ($app, $submissionVars, $formVars) {

                if (!$this->validateSettingsVars($submissionVars, $formVars)) {
                    return;
                }

                if (!$this->saveSiteSettings($submissionVars)) {
                    return;
                }

                $app->internal_services->system_messages->addSuccessMessage(elgg_echo('install:success:settings'));

                return $this->continueToNextStep('settings');
            };

            $response = $getResponse();
            if ($response) {
                return $response;
            }
        }

        $formVars = $this->makeFormSticky($formVars, $submissionVars);

        return $this->render('settings', ['variables' => $formVars]);
    }

    protected function runAdmin($submissionVars) {
        $app = $this->getApp();

        $formVars = [
            'displayname' => [
                'type' => 'text',
                'value' => '',
                'required' => true,
            ],
            'email' => [
                'type' => 'email',
                'value' => '',
                'required' => true,
            ],
            'username' => [
                'type' => 'text',
                'value' => '',
                'required' => true,
            ],
            'password1' => [
                'type' => 'password',
                'value' => '',
                'required' => true,
                'pattern' => '.{6,}',
            ],
            'password2' => [
                'type' => 'password',
                'value' => '',
                'required' => true,
            ],
        ];

        if ($this->is_action) {
            $getResponse = function () use ($app, $submissionVars, $formVars) {
                if (!$this->validateAdminVars($submissionVars, $formVars)) {
                    return;
                }

                if (!$this->createAdminAccount($submissionVars, $this->autoLogin)) {
                    return;
                }

                $app->internal_services->system_messages->addSuccessMessage(elgg_echo('install:success:admin'));

                return $this->continueToNextStep('admin');
            };

            $response = $getResponse();
            if ($response) {
                return $response;
            }
        }

        // Bit of a hack to get the password help to show right number of characters
        // We burn the value into the stored translation.
        $app = $this->getApp();
        $lang = $app->internal_services->translator->getCurrentLanguage();
        $translations = $app->internal_services->translator->getLoadedTranslations();
        $app->internal_services->translator->addTranslation($lang, [
            'install:admin:help:password1' => sprintf(
                $translations[$lang]['install:admin:help:password1'],
                $app->internal_services->config->min_password_length
            ),
        ]);

        $formVars = $this->makeFormSticky($formVars, $submissionVars);

        return $this->render('admin', ['variables' => $formVars]);
    }

    protected function runComplete() {

        // nudge to check out settings
        $link = elgg_view_url(elgg_normalize_url('admin/site_settings'), elgg_echo('install:complete:admin_notice:link_text'));
        $notice = elgg_format_element('p', [], elgg_echo('install:complete:admin_notice', [$link]));

        $custom_index_link = elgg_view_url(elgg_normalize_url('admin/plugin_settings/custom_index'), elgg_echo('admin:plugin_settings'));
        $notice .= elgg_format_element('p', [], elgg_echo('install:complete:admin_notice:custom_index', [$custom_index_link]));

        elgg_add_admin_notice('fresh_install', $notice);

        $result = $this->render('complete');

        elgg_delete_directory(Paths::sanitize(sys_get_temp_dir()) . 'elgginstaller/');

        return $result;
    }

    protected function getSteps() {
        return $this->steps;
    }

    protected function getCurrentStep() {
        $step = get_input('step', 'welcome');
        
        if (!in_array($step, $this->getSteps())) {
            $step = 'welcome';
        }
        
        return $step;
    }

    protected function continueToNextStep($currentStep) {
        $this->is_action = false;

        return new \Elgg\Http\RedirectResponse($this->getNextStepUrl($currentStep));
    }

    protected function getNextStep($currentStep) {
        $index = 1 + array_search($currentStep, $this->steps);
        
        return $this->steps[$index] ?? null;
    }

    protected function getNextStepUrl($currentStep) {
        $app = $this->getApp();
        $nextStep = $this->getNextStep($currentStep);

        return $app->internal_services->config->wwwroot . "install.php?step={$nextStep}";
    }

    protected function determineInstallStatus() {
        $app = $this->getApp();

        $path = Config::resolvePath();
        if (!is_file($path) || !is_readable($path)) {
            return;
        }

        $this->loadSettingsFile();

        $this->has_completed['config'] = true;

        // must be able to connect to database to jump install steps
        $dbSettingsPass = $this->checkDatabaseSettings(
            $app->internal_services->config->dbuser,
            $app->internal_services->config->dbpass,
            $app->internal_services->config->dbname,
            $app->internal_services->config->dbhost,
            $app->internal_services->config->dbport
        );

        if (!$dbSettingsPass) {
            return;
        }

        $db = $app->internal_services->db;

        try {
            // check that the config table has been created
            $result = $db->getConnection('read')->executeQuery('SHOW TABLES');
            if (empty($result)) {
                return;
            }
            
            foreach ($result->fetchAllAssociative() as $table) {
                if (in_array("{$db->prefix}config", $table)) {
                    $this->has_completed['database'] = true;
                }
            }
            
            if ($this->has_completed['database'] === false) {
                return;
            }

            // check that the config table has entries
            $qb = \Elgg\Database\Select::fromTable('config');
            $qb->select('COUNT(*) AS total');

            $result = $db->getDataRow($qb);
            if (!empty($result) && $result->total > 0) {
                $this->has_completed['settings'] = true;
            } else {
                return;
            }

            // check that the users entity table has an entry
            $qb = \Elgg\Database\Select::fromTable('entities', 'e');
            $qb->select('COUNT(*) AS total')
                ->where($qb->compare('type', '=', 'user', ELGG_VALUE_STRING));

            $result = $db->getDataRow($qb);
            if (!empty($result) && $result->total > 0) {
                $this->has_completed['admin'] = true;
            } else {
                return;
            }
        } catch (DatabaseException $ex) {
            throw new InstallationException('Elgg can not connect to the database: ' . $ex->getMessage(), $ex->getCode(), $ex);
        }
    }

    protected function checkInstallCompletion($step) {
        if ($step === 'complete') {
            return;
        }
        
        if (!in_array(false, $this->has_completed)) {
            // install complete but someone is trying to view an install page
            return new \Elgg\Http\RedirectResponse('/');
        }
    }

    protected function resumeInstall($step) {
        // only do a resume from the first step
        if ($step !== 'welcome') {
            return null;
        }

        if ($this->has_completed['database'] === false) {
            return null;
        }

        if ($this->has_completed['settings'] === false) {
            return new \Elgg\Http\RedirectResponse('install.php?step=settings');
        }

        if ($this->has_completed['admin'] === false) {
            return new \Elgg\Http\RedirectResponse('install.php?step=admin');
        }

        // everything appears to be set up
        return new \Elgg\Http\RedirectResponse('install.php?step=complete');
    }

    protected function finishBootstrapping($step) {

        $app = $this->getApp();

        $index_db = array_search('database', $this->getSteps());
        $index_step = array_search($step, $this->getSteps());

        if ($index_step > $index_db) {
            // once the database has been created, load rest of engine

            // dummy site needed to boot
            $app->internal_services->config->site = new \ElggSite();

            $app->bootCore();
        }
    }

    protected function loadSettingsFile() {
        try {
            $app = $this->getApp();

            $config = Config::factory();
            $app->internal_services->set('config', $config);

            // in case the DB instance is already captured in services, we re-inject its settings.
            $app->internal_services->db->resetConnections(DbConfig::fromElggConfig($config));
        } catch (\Exception $e) {
            throw new InstallationException(elgg_echo('InstallationException:CannotLoadSettings'), 0, $e);
        }
    }

    protected function makeFormSticky($formVars, $submissionVars) {
        foreach ($submissionVars as $field => $value) {
            $formVars[$field]['value'] = $value;
        }

        return $formVars;
    }

    /* Requirement checks support methods */

    protected function isInstallDirWritable(&$report) {
        if (!is_writable(Paths::projectConfig())) {
            $report['settings'] = [
                [
                    'severity' => 'error',
                    'message' => elgg_echo('install:check:installdir', [Paths::PATH_TO_CONFIG]),
                ]
            ];

            return false;
        }

        return true;
    }

    protected function checkSettingsFile(&$report = []) {
        if (!is_file(Config::resolvePath())) {
            return false;
        }

        if (!is_readable(Config::resolvePath())) {
            $report['settings'] = [
                [
                    'severity' => 'error',
                    'message' => elgg_echo('install:check:readsettings'),
                ]
            ];
        }

        return true;
    }

    protected function checkPHP(&$report) {
        $phpReport = [];

        if (version_compare(PHP_VERSION, self::PHP_MINIMAL_VERSION, '<')) {
            $phpReport[] = [
                'severity' => 'error',
                'message' => elgg_echo('install:check:php:version', [self::PHP_MINIMAL_VERSION, PHP_VERSION]),
            ];
        }

        $this->checkPhpExtensions($phpReport);

        $this->checkPhpDirectives($phpReport);

        if (count($phpReport) == 0) {
            $phpReport[] = [
                'severity' => 'success',
                'message' => elgg_echo('install:check:php:success'),
            ];
        }

        $report['php'] = $phpReport;
    }

    protected function checkPhpExtensions(&$phpReport) {
        $extensions = get_loaded_extensions();
        $requiredExtensions = [
            'pdo_mysql',
            'json',
            'xml',
            'gd',
        ];
        foreach ($requiredExtensions as $extension) {
            if (!in_array($extension, $extensions)) {
                $phpReport[] = [
                    'severity' => 'error',
                    'message' => elgg_echo('install:check:php:extension', [$extension]),
                ];
            }
        }

        $recommendedExtensions = [
            'mbstring',
        ];
        foreach ($recommendedExtensions as $extension) {
            if (!in_array($extension, $extensions)) {
                $phpReport[] = [
                    'severity' => 'warning',
                    'message' => elgg_echo('install:check:php:extension:recommend', [$extension]),
                ];
            }
        }
    }

    protected function checkPhpDirectives(&$phpReport) {
        if (ini_get('open_basedir')) {
            $phpReport[] = [
                'severity' => 'warning',
                'message' => elgg_echo('install:check:php:open_basedir'),
            ];
        }

        if (ini_get('safe_mode')) {
            $phpReport[] = [
                'severity' => 'warning',
                'message' => elgg_echo('install:check:php:safe_mode'),
            ];
        }

        if (ini_get('arg_separator.output') !== '&') {
            $separator = htmlspecialchars(ini_get('arg_separator.output'));
            $phpReport[] = [
                'severity' => 'error',
                'message' => elgg_echo('install:check:php:arg_separator', [$separator]),
            ];
        }

        if (ini_get('register_globals')) {
            $phpReport[] = [
                'severity' => 'error',
                'message' => elgg_echo('install:check:php:register_globals'),
            ];
        }

        if (ini_get('session.auto_start')) {
            $phpReport[] = [
                'severity' => 'error',
                'message' => elgg_echo('install:check:php:session.auto_start'),
            ];
        }
    }

    protected function checkRewriteRules(&$report) {
        $app = $this->getApp();

        $tester = new RewriteTester();
        $url = $app->internal_services->config->wwwroot;
        $url .= Request::REWRITE_TEST_TOKEN . '?' . http_build_query([
            Request::REWRITE_TEST_TOKEN => '1',
        ]);
        $report['rewrite'] = [$tester->run($url)];
    }

    protected function countNumConditions($report, $condition) {
        $count = 0;
        foreach ($report as $checks) {
            foreach ($checks as $check) {
                if ($check['severity'] === $condition) {
                    $count++;
                }
            }
        }

        return $count;
    }

    protected function validateDatabaseVars($submissionVars, $formVars) {

        $app = $this->getApp();

        foreach ($formVars as $field => $info) {
            if ($info['required'] === true && !$submissionVars[$field]) {
                $name = elgg_echo("install:database:label:{$field}");
                $app->internal_services->system_messages->addErrorMessage(elgg_echo('install:error:requiredfield', [$name]));

                return false;
            }
        }

        if (!empty($submissionVars['wwwroot']) && !\Elgg\Http\Urls::isValidMultiByteUrl($submissionVars['wwwroot'])) {
            $save_value = $this->sanitizeInputValue($submissionVars['wwwroot']);
            $app->internal_services->system_messages->addErrorMessage(elgg_echo('install:error:wwwroot', [$save_value]));

            return false;
        }

        // check that data root is absolute path
        if (stripos(PHP_OS, 'win') === 0) {
            if (strpos($submissionVars['dataroot'], ':') !== 1) {
                $save_value = $this->sanitizeInputValue($submissionVars['dataroot']);
                $app->internal_services->system_messages->addErrorMessage(elgg_echo('install:error:relative_path', [$save_value]));

                return false;
            }
        } else {
            if (!str_starts_with($submissionVars['dataroot'], '/')) {
                $save_value = $this->sanitizeInputValue($submissionVars['dataroot']);
                $app->internal_services->system_messages->addErrorMessage(elgg_echo('install:error:relative_path', [$save_value]));

                return false;
            }
        }

        // check that data root exists
        if (!is_dir($submissionVars['dataroot'])) {
            $save_value = $this->sanitizeInputValue($submissionVars['dataroot']);
            $app->internal_services->system_messages->addErrorMessage(elgg_echo('install:error:datadirectoryexists', [$save_value]));

            return false;
        }

        // check that data root is writable
        if (!is_writable($submissionVars['dataroot'])) {
            $save_value = $this->sanitizeInputValue($submissionVars['dataroot']);
            $app->internal_services->system_messages->addErrorMessage(elgg_echo('install:error:writedatadirectory', [$save_value]));

            return false;
        }

        // check that data root is not subdirectory of Elgg root
        if (stripos($submissionVars['dataroot'], Paths::project()) === 0) {
            $save_value = $this->sanitizeInputValue($submissionVars['dataroot']);
            $app->internal_services->system_messages->addErrorMessage(elgg_echo('install:error:locationdatadirectory', [$save_value]));

            return false;
        }

        // according to postgres documentation: SQL identifiers and key words must
        // begin with a letter (a-z, but also letters with diacritical marks and
        // non-Latin letters) or an underscore (_). Subsequent characters in an
        // identifier or key word can be letters, underscores, digits (0-9), or dollar signs ($).
        // Refs #4994
        if (!empty($submissionVars['dbprefix']) && !preg_match('/^[a-zA-Z_][\w]*$/', $submissionVars['dbprefix'])) {
            $app->internal_services->system_messages->addErrorMessage(elgg_echo('install:error:database_prefix'));

            return false;
        }

        return $this->checkDatabaseSettings(
            $submissionVars['dbuser'],
            $submissionVars['dbpassword'],
            $submissionVars['dbname'],
            $submissionVars['dbhost'],
            $submissionVars['dbport']
        );
    }

    protected function checkDatabaseSettings($user, $password, $dbname, $host, $port) {
        $app = $this->getApp();

        $config = new DbConfig((object) [
            'dbhost' => $host,
            'dbport' => $port,
            'dbuser' => $user,
            'dbpass' => $password,
            'dbname' => $dbname,
            'dbencoding' => 'utf8mb4',
        ]);
        $db = new Database($config, $app->internal_services->queryCache);

        try {
            $db->getConnection('read')->executeQuery('SELECT 1');
        } catch (DatabaseException $e) {
            if (str_starts_with($e->getMessage(), "Elgg couldn't connect")) {
                $app->internal_services->system_messages->addErrorMessage(elgg_echo('install:error:databasesettings'));
            } else {
                $save_value = $this->sanitizeInputValue($dbname);
                $app->internal_services->system_messages->addErrorMessage(elgg_echo('install:error:nodatabase', [$save_value]));
            }

            return false;
        }

        // check MySQL version
        $version = $db->getServerVersion();
        $min_version = $db->isMariaDB() ? self::MARIADB_MINIMAL_VERSION : self::MYSQL_MINIMAL_VERSION;
        
        if (version_compare($version, $min_version, '<')) {
            $app->internal_services->system_messages->addErrorMessage(elgg_echo('install:error:database_version', [$min_version, $version]));

            return false;
        }

        return true;
    }

    protected function createSettingsFile($params) {
        $app = $this->getApp();

        $template = Application::elggDir()->getContents('elgg-config/settings.example.php');
        if (!$template) {
            $app->internal_services->system_messages->addErrorMessage(elgg_echo('install:error:readsettingsphp'));

            return false;
        }

        foreach ($params as $k => $v) {
            // do some sanitization
            switch ($k) {
                case 'dataroot':
                    $v = Paths::sanitize($v);
                    break;
                case 'dbpassword':
                    $v = addslashes($v);
                    break;
            }

            $template = str_replace('{{' . $k . '}}', $v, $template);
        }

        $result = file_put_contents(Config::resolvePath(), $template);
        if ($result === false) {
            $app->internal_services->system_messages->addErrorMessage(elgg_echo('install:error:writesettingphp'));

            return false;
        }

        $config = (object) [
            'dbhost' => elgg_extract('dbhost', $params, 'localhost'),
            'dbport' => elgg_extract('dbport', $params, 3306),
            'dbuser' => elgg_extract('dbuser', $params),
            'dbpass' => elgg_extract('dbpassword', $params),
            'dbname' => elgg_extract('dbname', $params),
            'dbencoding' => elgg_extract('dbencoding', $params, 'utf8mb4'),
            'dbprefix' => elgg_extract('dbprefix', $params, 'elgg_'),
        ];

        $dbConfig = new DbConfig($config);
        $this->getApp()->internal_services->set('dbConfig', $dbConfig);
        $this->getApp()->internal_services->db->resetConnections($dbConfig);

        return true;
    }

    protected function connectToDatabase() {
        try {
            $app = $this->getApp();
            $app->internal_services->db->setupConnections();
        } catch (DatabaseException $e) {
            $app->internal_services->system_messages->addErrorMessage($e->getMessage());

            return false;
        }

        return true;
    }

    protected function installDatabase() {
        try {
            return $this->getApp()->migrate();
        } catch (\Exception $e) {
            return false;
        }
    }

    protected function createDataDirectory(&$submissionVars, $formVars) {
        // did the user have option of Elgg creating the data directory
        if ($formVars['dataroot']['type'] != 'combo') {
            return true;
        }

        // did the user select the option
        if ($submissionVars['dataroot'] != 'dataroot-checkbox') {
            return true;
        }

        $dir = \Elgg\Project\Paths::sanitize($submissionVars['path']) . 'data';
        if (file_exists($dir) || mkdir($dir, 0755)) {
            $submissionVars['dataroot'] = $dir;
            if (!file_exists("{$dir}/.htaccess")) {
                $htaccess = "Order Deny,Allow\nDeny from All\n";
                if (!file_put_contents("$dir/.htaccess", $htaccess)) {
                    return false;
                }
            }

            return true;
        }

        return false;
    }

    protected function validateSettingsVars($submissionVars, $formVars) {
        $app = $this->getApp();

        foreach ($formVars as $field => $info) {
            $submissionVars[$field] = trim($submissionVars[$field]);
            if ($info['required'] === true && $submissionVars[$field] === '') {
                $name = elgg_echo("install:settings:label:{$field}");
                $app->internal_services->system_messages->addErrorMessage(elgg_echo('install:error:requiredfield', [$name]));

                return false;
            }
        }

        // check that email address is email address
        if ($submissionVars['siteemail'] && !elgg_is_valid_email((string) $submissionVars['siteemail'])) {
            $save_value = $this->sanitizeInputValue($submissionVars['siteemail']);
            $app->internal_services->system_messages->addErrorMessage(elgg_echo('install:error:emailaddress', [$save_value]));

            return false;
        }

        return true;
    }

    protected function saveSiteSettings($submissionVars) {
        $app = $this->getApp();

        $site = elgg_get_site_entity();

        if (!$site->guid) {
            $site = new \ElggSite();
            $site->name = strip_tags($submissionVars['sitename']);
            $site->access_id = ACCESS_PUBLIC;
            $site->email = $submissionVars['siteemail'];
            $site->save();
        }

        if ($site->guid !== 1) {
            $app->internal_services->system_messages->addErrorMessage(elgg_echo('install:error:createsite'));

            return false;
        }

        $app->internal_services->config->site = $site;

        $sets = [
            'installed' => time(),
            'simplecache_enabled' => 1,
            'system_cache_enabled' => 1,
            'simplecache_minify_js' => true,
            'simplecache_minify_css' => true,
            'lastcache' => time(),
            'language' => 'en',
            'default_access' => $submissionVars['siteaccess'],
            'allow_registration' => false,
            'require_admin_validation' => false,
            'walled_garden' => false,
            'allow_user_default_access' => '',
            'default_limit' => 10,
        ];

        foreach ($sets as $key => $value) {
            elgg_save_config($key, $value);
        }

        try {
            _elgg_services()->plugins->generateEntities();

            $app->internal_services->reset('plugins');
            
            $plugins = $app->internal_services->plugins->find('any');

            foreach ($plugins as $plugin) {
                $plugin_config = $plugin->getStaticConfig('plugin', []);
                if (!elgg_extract('activate_on_install', $plugin_config, false)) {
                    continue;
                }
                
                try {
                    $plugin->activate();
                } catch (PluginException $e) {
                    // do nothing
                }
            }

            // Wo don't need to run upgrades on new installations
            $app->internal_services->events->unregisterHandler('create:after', 'object', \Elgg\Upgrade\CreateAdminNoticeHandler::class);
            $upgrades = $app->internal_services->upgradeLocator->locate();
            foreach ($upgrades as $upgrade) {
                $upgrade->setCompleted();
            }
        } catch (\Exception $e) {
            $app->internal_services->logger->log(\Psr\Log\LogLevel::ERROR, $e);
        }

        return true;
    }

    protected function validateAdminVars($submissionVars, $formVars) {

        $app = $this->getApp();

        foreach ($formVars as $field => $info) {
            if ($info['required'] === true && !$submissionVars[$field]) {
                $name = elgg_echo("install:admin:label:{$field}");
                $app->internal_services->system_messages->addErrorMessage(elgg_echo('install:error:requiredfield', [$name]));

                return false;
            }
        }

        if ($submissionVars['password1'] !== $submissionVars['password2']) {
            $app->internal_services->system_messages->addErrorMessage(elgg_echo('install:admin:password:mismatch'));

            return false;
        }

        if (trim($submissionVars['password1']) === '') {
            $app->internal_services->system_messages->addErrorMessage(elgg_echo('install:admin:password:empty'));

            return false;
        }

        $minLength = $app->internal_services->configTable->get('min_password_length');
        if (strlen($submissionVars['password1']) < $minLength) {
            $app->internal_services->system_messages->addErrorMessage(elgg_echo('install:admin:password:tooshort'));

            return false;
        }

        // check that email address is email address
        if ($submissionVars['email'] && !elgg_is_valid_email((string) $submissionVars['email'])) {
            $save_value = $this->sanitizeInputValue($submissionVars['email']);
            $app->internal_services->system_messages->addErrorMessage(elgg_echo('install:error:emailaddress', [$save_value]));

            return false;
        }

        return true;
    }

    protected function createAdminAccount($submissionVars, $login = false) {
        $app = $this->getApp();

        try {
            $user = elgg_register_user([
                'username' => $submissionVars['username'],
                'password' => $submissionVars['password1'],
                'name' => $submissionVars['displayname'],
                'email' => $submissionVars['email'],
            ]);
        } catch (RegistrationException $e) {
            $app->internal_services->system_messages->addErrorMessage($e->getMessage());

            return false;
        }

        $ia = $app->internal_services->session_manager->setIgnoreAccess(true);
        if (!$user->makeAdmin()) {
            $app->internal_services->system_messages->addErrorMessage(elgg_echo('install:error:adminaccess'));
        }
        
        $app->internal_services->session_manager->setIgnoreAccess($ia);

        // add validation data to satisfy user validation plugins
        $user->validated = true;
        $user->validated_method = 'admin_user';

        if (!$login) {
            return true;
        }

        try {
            elgg_login($user);
        } catch (LoginException $ex) {
            $app->internal_services->system_messages->addErrorMessage(elgg_echo('install:error:adminlogin'));
            
            return false;
        }

        return true;
    }
    
    protected function sanitizeInputValue($input_value) {
        if (is_array($input_value)) {
            return array_map([$this, __FUNCTION__], $input_value);
        }
        
        if (!is_string($input_value)) {
            return $input_value;
        }
        
        return htmlspecialchars($input_value);
    }
}