Feature: #67808 - Introduce Application classes for entry points and equivalent RequestHandlers

See Issue #67808

Description

All entry points are encapsulating all previous initialization code in an Application class depending on the TYPO3_MODE and several context-dependant constraints. Each Application class registers Request Handlers to the TYPO3 Bootstrap to run a certain request type (e.g. eID or TSFE-logic, or AJAX requests in the Backend). Each Application is handed over the Class Loader provided by Composer.

There are four types of Applications provided by the TYPO3 Core:

TYPO3CMSFrontendHttpApplication

All incoming web requests coming to index.php in the main directory, handling all TSFE and eID requests. The Application sets TYPO3_MODE=FE very early. The Application checks if all configuration is given, otherwise redirects to the TYPO3 Install Tool.

TYPO3CMSBackendHttpApplication

All incoming web requests for any regular Backend call inside typo3/*. This handles three types of Request Handlers:

  • The AJAX Request Handler, which is triggered on requests with an "ajaxID" GET Parameter given.
  • The Backend Module Request Handler, which handles all types of modules triggered on requests with an "M" GET Parameter
  • The regular Request handler for typical other backend calls on index.php.

The Application checks if all configuration is given, otherwise redirects to the TYPO3 Install Tool.

TYPO3CMSBackendConsoleApplication

All CLI Requests handled by cli_dispatch.php. Only executes the parts that are necessary for Backend CLI Scripts used with the cliKey syntax. The typical CliRequestHandler is used for handling requests set up by this Application.

TYPO3CMSInstallHttpApplication

The install tool Application only runs with a very limited bootstrap set up with a Failsafe Package Manager not taking the ext_localconf.php scripts of installed extensions into account.