.. ==================================================
.. FOR YOUR INFORMATION
.. --------------------------------------------------
.. -*- coding: utf-8 -*- with BOM.

.. include:: ../Includes.txt

.. _Bootstarpping:


=============
Bootstrapping
=============

Bootstrapping basically happens in 3 parts:

    1. Analysis of the environment
    2. Reading the configuration
    3. Firering up the global tool chain: DB, Caching, etc.

Running :code:`typo3/index.php`::

    * require vendor/autoload.php
        * This file is generated by composer to find all classes.
        * It is configurated by different composer.json files.
    * new Frontend\Http\Application
        * bootstrap = Core\Bootstrap\getInstance (calls __construct)
            * getenv TYPO3_CONTEXT ?: REDIRECT_TYPO3_CONTEXT ?: "Production"
            * new Core\ApplicationContext
                * A TYPO3 Application context is something like "Production", "Development",
                * "Production/StagingSystem", and is set using the TYPO3_CONTEXT environment variable.
                * Mainly, you will use $context->isProduction(), $context->isTesting() and
                * $context->isDevelopment() inside your custom code.
            * defineTypo3RequestTypes
                - TYPO3_REQUESTTYPE_FE
                - TYPO3_REQUESTTYPE_BE
                - TYPO3_REQUESTTYPE_CLI
                - TYPO3_REQUESTTYPE_AJAX
                - TYPO3_REQUESTTYPE_INSTALL
        * bootstrap->initializeClassLoader
            registers the classloader as an "early instance"
        * bootstrap->setRequestType
            - TYPO3_REQUESTTYPE: one of the above
        * bootstrap->baseSetup
            * SystemEnvironmentBuilder::run
                * defineBaseConstants
                    - version info
                    - external links
                    - NUL, TAB, LF, CR, SUB, CRLF
                    - security
                    - OS
                    - errors
                * definePaths
                    - TYPO3_mainDir
                    - PATH_thisScript
                    - PATH_site
                    - PATH_typo3
                    - PATH_typo3conf
                * checkMainPathsExist
                    - .../sysext
                * initializeGlobalVariables
                    reset $GLOBALS: error, TYPO3_MISC, T3_VAR, T3_SERVICES
                * initializeGlobalTimeTrackingVariables
                    - variables for time tracking, logging, etc.
                * initializeBasicErrorReporting
                    error_reporting(E_ALL & ~(E_STRICT | E_NOTICE | E_DEPRECATED));
            * GeneralUtility::presetApplicationContext
                sets GeneralUtility::applicationContext
        * bootstrap->checkIfEssentialConfigurationExists
            * new Core\Configuration\ConfigurationManager
                register as "early instance"
                (rather ugly side effect!)
            * check for
                - LocalConfiguration.php (cm->getLocalConfigurationFileLocation)
                - PATH_typo3conf . PackageStates.php
            * or bootstrap->redirectToInstallTool
        * loop bootstrap->registerRequestHandlerImplementation
            - Frontend\Http\RequestHandler
            - Frontend\Http\EidRequestHandler
        * bootstrap->configure
            * startOutputBuffering
              ob_start
            * loadConfigurationAndInitialize
                * populateLocalConfiguration
                * initializeErrorHandling
                * optionally disableCoreCache
                * initializeCachingFramework
                * initializePackageManagement
                * initializeRuntimeActivatedPackagesFromConfiguration
                * defineUserAgentConstant
                * registerExtDirectComponents
                * setCacheHashOptions
                * setDefaultTimezone
                * initializeL10nLocales
                * convertPageNotFoundHandlingToBoolean
                * setMemoryLimit
                * optionally: ensureClassLoadingInformationExists
            * loadTypo3LoadedExtAndExtLocalconf
                * ExtensionManagementUtility::loadExtLocalconf
            * setFinalCachingFrameworkCacheConfiguration
                * CacheManager->setCacheConfigurations:
                    $TYPO3_CONF_VARS.SYS.caching.cacheConfigurations
            * defineLoggingAndExceptionConstants
                This constants are set from variables!!!
                - TYPO3_DLOG: $TYPO3_CONF_VARS.SYS.enable_DLOG
                - TYPO3_ERROR_DLOG: $TYPO3_CONF_VARS.SYS.enable_errorDLOG
                - TYPO3_EXCEPTION_DLOG: $TYPO3_CONF_VARS.SYS.enable_exceptionDLOG
            * unsetReservedGlobalVariables
                * Unsetting reserved global variables:
                * Those are set in "ext:core/ext_tables.php" file or otherwise:
                    - PAGES_TYPES
                    - TCA
                    - TBE_MODULES
                    - TBE_STYLES
                    - BE_USER
                    - TBE_MODULES_EXT
                    - TCA_DESCR
                    - LOCAL_LANG
            * initializeTypo3DbGlobal
                * creates Core\Database\DatabaseConnection
                * configures it in a complex process
                  * This includes:
                    $TYPO3_CONF_VARS.DB.Connections.Default.persistentConnection
                * Set it to $TYPO3_DB
                * $TYPO3_DB->initialize
                  Delegated to DBAL
    * ->run