Initiative Title: PSR-15 Middlewares for TYPO3

The main goal of the first part of the persistence initiative is cleaning up the existing data handling layers in TYPO3 and providing a unified persistence layer for use in all contexts and by extension developers and the core alike.

The PSR-15 middleware specification was released on 22nd of january 2018.

TYPO3 should support PSR-15 middlewares out-of-the box.

Supporting PSR-15 middlewares improves interoperability with independent libraries and would superseed hooks like $GLOBALS['TYPO3_CONF_VARS']['SC_OPTIONS']['tslib/index_ts.php']['preprocessRequest'].

Additionally implementing PSR-7 for request and responses throughout the core enables us to group all request related settings in one place allowing to simulate context dependent requests in another context (for example frontend requests done on CLI or backend).

• Introduce PSR-15 middlewares (done)
• Refactor backend bootstrap/request handler code to middlewares (partly done)
• Refactor frontend bootstrap/request handler code to middlewares (partly done)
• Deprecate GeneralUtility::getIndpEnv vars and replace with request
• Deprecate GeneralUtility::_GET / _POST / _GP and replace with request
• Add request to TSFE via feature flag (and use it in TSFE)
• Add request context object to frontend request
• Extract connectToDb, __construct, initFeUser, initBeUser, AdminPanelInit from TSFE to middlewares
  • FrontendInitializor (done)
  • FrontendUserInitializor
  • BackendUserInitializor
  • AdminPanelInitializor (done)
• ...
   

Epic-Link: https://forge.typo3.org/issues/83894 (note that only the tickets currently in progress or done are listed here)

• Get in touch via Slack: #initiative-psr15
• Take a look at current tickets: Overview / Epic #83894

• https://www.php-fig.org/psr/psr-7/
• https://www.php-fig.org/psr/psr-15/