Since version 6.0, TYPO3 CMS uses PHP namespaces for all classes in the Core.
The general structure of namespaces is the following:
For the Core, the vendor name is
TYPO3\CMS and the package name corresponds
to a system extension.
All classes must be located inside the
Classes folder at the root of the
(system) extension. The category name may contain several segments that correspond
to the path inside the
Finally the class name is the same as the corresponding file name, without the
“UpperCamelCase” is used for all segments.
The Extension compatibility6 contains a full mapping of old to new class names, which will help you find your way around the new naming. You can find the source code at its Github repo in file Migrations/Code/LegacyClassesForIde.php.
The good old
t3lib_div class has been renamed to:
This means that the class is now found in the “core” system extension, in folder
Classes/Utility, in a file named
Usage in extensions¶
Extension developers are free to use their own vendor name. Important: It may consist of one segment only. Vendor names must start with an uppercase character and are usually written in UpperCamelCase style. In order to avoid problems with different filesystems, only the characters a-z, A-Z, 0-9 and the dash sign “-” are allowed for package names – don’t use special characters:
// good vendor name: \Webcompany // wrong vendor name: \Web\Company
The vendor name
TYPO3\CMS is reserved and may not be used by extensions!
The package name corresponds to the extension key. Underscores in the extension key are removed in the namespace and replaced by upper camel-case. So extension key:
in the namespace.
As mentioned above, all classes must be located in the
Classes folder inside
your extension. All sub-folders translate to a segment of the category name and the class
name is the file name without the
Looking at the “examples” extension, class:
corresponds to namespace:
Inside the class, the namespace is declared as:
<?php namespace Documentation\Examples\Controller;
Namespaces in Extbase¶
When registering components in Extbase, the vendor name must be used on top of the extension key.
For a backend module:
\TYPO3\CMS\Extbase\Utility\ExtensionUtility::registerModule( '<vendorName>.<ExtensionName>, ... );
For a frontend module:
\TYPO3\CMS\Extbase\Utility\ExtensionUtility::configurePlugin( '<vendorName>.<ExtensionName>, ... );
- Do not forget the dot after the vendor name.
- Do not use dots inside the vendor name.
Namespaces for test classes¶
As for ordinary classes, namespaces for test classes start with a vendor name followed by the extension key.
All test classes reside in a
Tests folder and thus the third segment
of the namespace must be “Tests”. Unit tests are located in a
which is the fourth segment of the namespace. Any further subfolders will
be subsequent segments.
So a test class in
EXT:foo_bar_baz/Tests/Unit/Bla/ will have as namespace
When creating instances using
the leading backslash must be omitted and all other backslashes escaped, even when using
single quotes. Thus the following code is correct:
$contentObject = \TYPO3\CMS\Core\Utility\GeneralUtility::makeInstance(TYPO3\CMS\Frontend\ContentObject\ContentObjectRenderer::class);
There is no need to use
include() statements. All classes that follow
namespace conventions will automatically located and included by the autoloader.