.. include:: ../../Includes.txt

=========================================
Feature: #84581 - Introduce Site Handling
=========================================

See :issue:`84581`

Description
===========

Site Handling has been added to TYPO3.

Its goal is to make managing multiple sites easier to understand and faster to do. Sites bring a variety of new
concepts to TYPO3 which we will explain below.

Take your time and read through the entire document since some concepts rely on each other.


typo3conf/sites folder
----------------------

New sites will live in the folder `typo3conf/sites/`. In the first iteration this folder will contain a file called
`config.yaml` which holds all configuration for a given site.

Note that if you are using a composer based installation, then the file location is `<project-root>/config/sites/<identifier>/config.yaml`

In the future this folder can (and should) be used for more files like Fluid templates, and Backend layouts.


config.yaml
-----------

.. code-block:: yaml

   # the rootPage Id (see below)
   rootPageId: 12
   # my base domain to run this site on. It either accepts a fully qualified URL or "/" to react to any domain name
   base: 'https://www.example.com/'
   # The language array
   languages:
     -
       # the TYPO3 sys_language_uid as you know it since... ever
       languageId: '0'
       # The internal name for this language. Unused for now, but in the future this will affect display in the backend
       title: English
       # optional navigation title which is used in HMENU.special = language
       navigationTitle: ''
       # Language base. Accepts either a fully qualified URL or a path segment like "/en/".
       base: /
       # sets the locale during frontend rendering
       locale: en_US.UTF-8
       # two-letter code for the language according to ISO-639 nomenclature (see https://en.wikipedia.org/wiki/List_of_ISO_639-1_codes)
       iso-639-1: en
       # FE href language
       hreflang: en-US
       # FE text direction
       direction: ltr
       # Language Identifier to use in localLang XLIFF files
       typo3Language: default
       # Flag Identifier
       flag: gb
     -
       languageId: '1'
       title: 'danish'
       navigationTitle: Dansk
       base: /da/
       locale: dk_DK.UTF-8
       iso-639-1: da
       hreflang: dk-DK
       direction: ltr
       typo3Language: default
       flag: dk
       fallbackType: strict
     -
       languageId: '2'
       title: Deutsch
       navigationTitle: ''
       base: 'https://www.beispiel.de'
       locale: de_DE.UTF-8
       iso-639-1: de
       hreflang: de-DE
       direction: ltr
       typo3Language: de
       flag: de
       # Enable content fallback
       fallbackType: fallback
       # Content fallback mode (order is important)
       fallbacks: '2,1,0'
   # Error Handling Array (order is important here)
   # Error Handlers will check the given status code, but the special value "0" will react to any error not configured
   # elsewhere in this configuration.
   errorHandling:
     -
       # HTTP Status Code to react to
       errorCode: '404'
       # The used ErrorHandler. In this case, it's "Display content from Page". See examples below for available options.
       errorHandler: Page
       # href to the content source to display (accepts both fully qualified URLs as well as TYPO3 internal link syntax
       errorContentSource: 't3://page?uid=8'
     -
       errorCode: '403'
       errorHandler: Fluid
       # Path to the Template File to show
       errorFluidTemplate: 'EXT:my_extension/Resources/Private/Templates/ErrorPages/403.html'
       # Optional Templates root path
       errorFluidTemplatesRootPath: 'EXT:my_extension/Resources/Private/Templates/ErrorPages'
       # Optional Layouts root path
       errorFluidLayoutsRootPath: 'EXT:my_extension/Resources/Private/Layouts/ErrorPages'
       # Optional Partials root path
       errorFluidPartialsRootPath: 'EXT:my_extension/Resources/Private/Partials/ErrorPages'
     -
       errorCode: '0'
       errorHandler: PHP
       # Fully qualified class name to a class that implements PageErrorHandlerInterface
       errorPhpClassFQCN: Vendor\ExtensionName\ErrorHandlers\GenericErrorhandler


All settings can also be edited via the backend module `Site Management > Configuration`.

Keep in mind that due to the nature of the module, comments or additional values in your :file:`config.yaml` file
**will** get deleted on saving.


site identifier
---------------

The site identifier is the name of the folder within `typo3conf/sites/` that will hold your configuration file(s). When
choosing an identifier make sure to stick to ASCII but you may also use `-`, `_` and `.` for convenience.


rootPageId
----------

Root pages are identified by one of these two properties:

* they are direct descendants of PID 0 (the root root page of TYPO3)
* they have the "Use as Root Page" property in `pages` set to true.


Configuration
=============

The new backend module relies on FormEngine to render the edit interface. Since the form data is not stored in
database records but in :file:`.yml` files, a couple of details have been extended of the default FormEngine code.

The render configuration is stored in :file:`typo3/sysext/backend/Configuration/SiteConfiguration/` in a format
syntactically identical to TCA. However, this is **not** loaded into :php:`$GLOBALS['TCA']` scope, and only a small
subset of TCA features is supported.

**Extending site configuration is experimental** and may change any time.

In practice the configuration can be extended, but only with very simple fields like the basic config type :php:`input`,
and even for this one not all features are possible, for example the :php:`eval` options are limited. The code throws
exceptions or just ignores settings it does not support. While some of the limits may be relaxed a bit over time, many
will be kept. The goal is to allow developers to extend the site configuration with a couple of simple things like
an input field for a Google API key. However it is **not possible to extend with complex TCA** like inline relations,
database driven select fields, Flex Form handling and similar.

The example below shows the experimental feature adding a field to site in an extensions file
:file:`Configuration/SiteConfiguration/Overrides/sites.php`. Note the helper methods of class
:php:`TYPO3\CMS\core\Utility\ExtensionManagementUtility` can not be used.

.. code-block:: php

    <?php
    // Experimental example to add a new field to the site configuration

    // Configure a new simple required input field to site
    $GLOBALS['SiteConfiguration']['site']['columns']['myNewField'] = [
        'label' => 'A new custom field',
        'config' => [
            'type' => 'input',
            'eval' => 'required',
        ],
    ];
    // And add it to showitem
    $GLOBALS['SiteConfiguration']['site']['types']['0']['showitem'] = str_replace(
        'base,',
        'base, myNewField, ',
        $GLOBALS['SiteConfiguration']['site']['types']['0']['showitem']
    );

The field will be shown in the edit form of the configuration module and it's value stored in the .yaml
file. Using the site object :php:`TYPO3\CMS\core\Site\Entity\Site`, the value can be fetched using
:php:`->getConfiguration()['myNewField']`.


Impact
======

The following TypoScript settings will be set based on `config.yaml` rather than needing to have them in your TypoScript
template:

* config.language
* config.htmlTag_dir
* config.htmlTag_langKey
* config.sys_language_uid
* config.sys_language_mode
* config.sys_language_isocode
* config.sys_language_isocode_default


Links to pages within a site can now be generated via **any** access of TYPO3, so in both BE and FE as well as CLI mode.

.. index:: Backend, Frontend, TypoScript
