Constants

Constants in TYPO3 define paths and database information. These values are global and cannot be changed. Constants are defined at various points during the bootstrap sequence.

To make the information below a bit more compact, namespaces were left out. Here are the fully qualified class names referred to below:

• "SystemEnvironmentBuilder" = \TYPO3\CMS\Core\Core\SystemEnvironmentBuilder

• "Bootstrap" = \TYPO3\CMS\Core\Core\Bootstrap

Check SystemEnvironmentBuilder::defineBaseConstants() for more constants.

Paths

Security related constant

FILE_DENY_PATTERN_DEFAULT

Default value of $GLOBALS['TYPO3_CONF_VARS']['BE']['fileDenyPattern'].

Defined in:

\TYPO3\CMS\Core\Resource\Security\FileNameValidator::FILE_DENY_PATTERN_DEFAULT

Example:

\\.(php[3-8]?|phpsh|phtml|pht|phar|shtml|cgi)(\\..*)?$|\\.pl$|^\\.htaccess$

Available in Frontend:

Yes

Filetypes

Different types of files constants are defined in TYPO3\CMS\Core\Resource\AbstractFile. These constants are available for different groups of files as documented in https://www.iana.org/assignments/media-types/media-types.xhtml

These file types are assigned to all FAL resources. They can, for example, be used in Fluid to decide how to render different types of files.

Constant	Value	Description
FILETYPE_UNKNOWN	0	Unknown
FILETYPE_TEXT	1	Any kind of text
FILETYPE_IMAGE	2	Any kind of image
FILETYPE_AUDIO	3	Any kind of audio
FILETYPE_VIDEO	4	Any kind of video
FILETYPE_APPLICATION	5	Any kind of application

HTTP status codes

The different status codes available are defined in TYPO3\CMS\Core\Utility\HttpUtility. These constants are defined as documented in https://www.iana.org/assignments/http-status-codes/http-status-codes.xhtml