[!!!][TASK] Remove typoscript option config.disableCharsetHeader

This option is obsolete nowadays, as PSR-7 is setting
the headers at the end of the script / when emitting
a Response, this way the header can be modified at any time.

Resolves: #97550
Releases: main
Change-Id: I0602e4fd0a20461d49a554f66f36442894e96fd4
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/74518

Tested-by: core-ci <typo3@b13.com>
Tested-by: Georg Ringer <georg.ringer@gmail.com>
Tested-by: Oliver Bartsch <bo@cedev.de>
Tested-by: Josef Glatz <josefglatz@gmail.com>
Tested-by: Benni Mack <benni@typo3.org>
Reviewed-by: Georg Ringer <georg.ringer@gmail.com>
Reviewed-by: Oliver Bartsch <bo@cedev.de>
Reviewed-by: Benni Mack <benni@typo3.org>

typo3/sysext/core/Documentation/Changelog/12.0/Breaking-97550-TypoScriptOptionConfigdisableCharsetHeaderRemoved.rst

+.. include:: /Includes.rst.txt
+
+.. _breaking-97550-1651697278
+
+========================================================================
+Breaking: #97550 - TypoScript option config.disableCharsetHeader removed
+========================================================================
+
+See :issue:`97550`
+
+Description
+===========
+
+The TypoScript flag :ts:`config.disableCharsetHeader` has been completely removed
+from TYPO3 Core.
+
+This option was used to avoid sending HTTP headers of type "Content-Type" to
+the client. This flag was mainly used to overcome a technical limitation to
+override the Content-Type information back in TYPO3 v4.x.
+
+
+Impact
+======
+
+TYPO3 now always sends the `Content-Type` header to the client in the TYPO3
+Frontend.
+
+
+Affected installations
+======================
+
+TYPO3 installations having this option enabled via TypoScript.
+
+
+Migration
+=========
+
+It is not needed to set this option. Even when Extbase plugins return JSON-based
+Responses, the Content-Type header is already modified.
+
+In special cases, when custom headers are required, it is possible to modify
+the headers via a PHP-based PSR-15 middleware, or via TypoScript with
+"config.additionalHeaders".
+
+.. index:: TypoScript, NotScanned, ext:frontend

typo3/sysext/extbase/Classes/Core/Bootstrap.php

@@ -163,24 +163,13 @@ class Bootstrap
             $this->clearCacheOnError();
         }
 
-        // In case TSFE is available and this is a json response, we have
-        // to take the TypoScript settings regarding charset into account.
-        // @todo Since HTML5 only utf-8 is a valid charset, this settings should be deprecated
+        // In case TSFE is available and this is a json response, we have to let TSFE know we have a specific Content-Type
         if (($typoScriptFrontendController = ($GLOBALS['TSFE'] ?? null)) instanceof TypoScriptFrontendController
             && str_starts_with($response->getHeaderLine('Content-Type'), 'application/json')
         ) {
-            // Unset the already defined Content-Type
+            // Do not send the header directly (see below)
             $response = $response->withoutHeader('Content-Type');
-            if (empty($typoScriptFrontendController->config['config']['disableCharsetHeader'])) {
-                // If the charset header is *not* disabled in configuration,
-                // TypoScriptFrontendController will send the header later with the Content-Type which we set here.
-                $typoScriptFrontendController->setContentType('application/json');
-            } else {
-                // Although the charset header is disabled in configuration, we *must* send a Content-Type header here.
-                // Content-Type headers optionally carry charset information at the same time.
-                // Since we have the information about the charset, there is no reason to not include the charset information although disabled in TypoScript.
-                $response = $response->withHeader('Content-Type', 'application/json; charset=utf-8');
-            }
+            $typoScriptFrontendController->setContentType('application/json');
         }
 
         if (headers_sent() === false) {

typo3/sysext/frontend/Classes/Controller/TypoScriptFrontendController.php

@@ -2165,10 +2165,8 @@ class TypoScriptFrontendController implements LoggerAwareInterface
      */
     public function applyHttpHeadersToResponse(ResponseInterface $response): ResponseInterface
     {
-        // Set header for charset-encoding unless disabled
-        if (empty($this->config['config']['disableCharsetHeader'])) {
-            $response = $response->withHeader('Content-Type', $this->contentType . '; charset=utf-8');
-        }
+        // Set header for content-type + charset-encoding
+        $response = $response->withHeader('Content-Type', $this->contentType . '; charset=utf-8');
         // Set header for content language unless disabled
         $contentLanguage = $this->language->getTwoLetterIsoCode();
         if (empty($this->config['config']['disableLanguageHeader']) && !empty($contentLanguage)) {

typo3/sysext/t3editor/Resources/Private/tsref.xml

@@ -315,11 +315,6 @@ This value is overridden by the value set in the page-record (field="cache_timeo
 Use this feature in templates supplying other content-types than HTML. That could be an image or a WAP-page!]]></description>
 			<default><![CDATA[false]]></default>
 		</property>
-		<property name="disableCharsetHeader" type="boolean">
-			<description><![CDATA[By default a HTTP header "Content-Type: text/html; charset..." is sent. This option will disable that.]]></description>
-			<default><![CDATA[
-]]></default>
-		</property>
 		<property name="disablePrefixComment" type="boolean">
 			<description><![CDATA[If set, the stdWrap property "prefixComment" will be disabled, thus preventing any revealing and spaceconsuming comments in the HTML source code.]]></description>
 			<default><![CDATA[

typo3/sysext/t3editor/Resources/Public/JavaScript/Mode/typoscript/typoscript.js

@@ -255,7 +255,6 @@
         'disableAllHeaderCode': kw('disableAllHeaderCode'),
         'disableAltText': kw('disableAltText'),
         'disableBodyTag': kw('disableBodyTag'),
-        'disableCharsetHeader': kw('disableCharsetHeader'),
         'disabled': kw('disabled'),
         'disableDelete': kw('disableDelete'),
         'disableHideAtCopy': kw('disableHideAtCopy'),