# Files and Locations¶

## Files¶

An extension consists of:

1. A directory named by the extension key (which is a worldwide unique identification string for the extension), usually located in typo3conf/ext for local extensions, or typo3/sysext for system extensions.
2. Standard files with reserved names for configuration related to TYPO3 (of which most are optional, see list below)
3. Any number of additional files for the extension functionality itself.

## Reserved File Names¶

This lists files within an extension that have a specific meaning by convention. TYPO3 will scan for reserved file names and use the content for specific functionality. For example, if a svg logo of your extension is placed at Resources/Public/Icons/Extension.svg, the Extension Manager will show that image.

Most of these files are not required. The exception is ext_emconf.php: You can not have a TYPO3 extension recognized by TYPO3 without this file.

In general, do not introduce your own files in the root directory of extensions with the name prefix ext_, because that is reserved.

– required

### ext_emconf.php¶

– required

Definition of extension properties. This is the only mandatory file in the extension. It describes the extension.

Name, category, status etc. are used by the Extension Manager. The content of this file is described in more details in Declaration File (ext_emconf.php). Note that it is auto-written by the Extension Manager when extensions are imported from the repository.

Note

If this file is not present, the Extension Manager will not find the extension.

– optional

Addition to LocalConfiguration.php. It should contain additional configuration of $GLOBALS['TYPO3_CONF_VARS']. This file contains hook definitions and plugin configuration. It must not contain a PHP encoding declaration. All ext_localconf.php files of loaded extensions are included right after the files typo3conf/LocalConfiguration.php and typo3conf/AdditionalConfiguration.php during TYPO3 bootstrap. Pay attention to the rules for the contents of these files. For more details, see the section below. ### ext_tables.php¶ – optional Contains extensions of existing tables, declaration of backend modules, etc. All code in such files is included after all the default definitions provided by the core and loaded after ext_localconf.php files during TYPO3 bootstrap. Pay attention to the rules for the contents of these files. For more details, see the section below. Note In old TYPO3 core versions, this file contained additions to the global $GLOBALS['TCA'] array. This changed since core version 6.2 to allow effective caching:

TCA definition of new database tables must be done entirely in Configuration/TCA/<table name>.php. These files are expected to contain the full TCA of the given table (as an array) and simply return it (with a return statement).

Customizations of existing tables must be done entirely in Configuration/TCA/Overrides/<table name>.php.

### ext_tables.sql¶

– optional

SQL definition of database tables.

This file should contain a table-structure dump of the tables used by the extension. It is used for evaluation of the database structure and is applied to the database when an extension is enabled.

If you add additional fields (or depend on certain fields) to existing tables you can also put them here. In that case insert a CREATE TABLE structure for that table, but remove all lines except the ones defining the fields you need, here is an example adding a column to the pages table:

CREATE TABLE pages (
tx_myext_field int(11) DEFAULT '0' NOT NULL,
);


TYPO3 will merge this table definition to the existing table definition when comparing expected and actual table definitions. Partial definitions can also contain indexes and other directives. They can also change existing table fields though that is not recommended, because it may create problems with the TYPO3 core and/or other extensions.

The ext_tables.sql file may not necessarily be “dumpable” directly to MySQL (because of the semi-complete table definitions allowed defining only required fields). But the Extension Manager or Install Tool can handle this.

TYPO3 parses ext_tables.sql files. TYPO3 expects that all table definitions in this file look like the ones produced by the mysqldump utility. Incorrect definitions may not be recognized by the TYPO3 SQL parser or may lead to MySQL errors, when TYPO3 tries to apply them. If TYPO3 is not running on MySQL or directly compatible other DBMS like MariaDB, the system will parse the file towards the target DBMS like PostgreSQL.

#### Auto generated structure¶

The database schema analyzer automatically creates TYPO3 “management” related database columns by reading a tables TCA and checking the [‘ctrl’] section for table capabilities. Field definitions in ext_tables.sql take precedence over automatically generated fields, so the core never overrides a manually specified column definition from an ext_tables.sql file.

### RequestMiddlewares.php¶

Full path to this file is: Configuration/RequestMiddlewares.php.

Configuration of user-defined middlewares for frontend and backend. Extensions that add middlewares or disable existing middlewares configure them in this file. The file must return an array with the configuration. For more details, see Configuring middlewares.

### Routes.php and AjaxRoutes.php¶

Full paths to these files are: Configuration/Backend/Routes.php and Configuration/Backend/AjaxRoutes.php.

Registry of backend routes. Extensions that add backend modules must register their routes here to be correctly linkable in the backend. The file must return an array with routing details. See core extensions like backend for examples.

### Configuration/Services.yaml¶

New in version 10.

Services can be configured in this file. TYPO3 uses it for:

A typical Configuration/Services.yaml may look like this:

Simplified Services.yaml from sysext: core
# Configuration/Services.yaml
services:
# general settings
_defaults:
autowire: true
autoconfigure: true
public: false

TYPO3\CMS\Core\:
resource: '../Classes/*'

# dependency injection (override public setting)
TYPO3\CMS\Core\Mail\Mailer:
public: true

TYPO3\CMS\Core\Command\SendEmailCommand:
tags:
- name: 'console.command'
command: 'mailer:spool:send'
- name: 'console.command'
command: 'swiftmailer:spool:send'
alias: true
schedulable: false


### Resources/Public/Icons/Extension.svg¶

Extension icon. If exists, this icon is displayed in the Extension Manager. Preferred is using an SVG file, Extension icon will look nicer when provided as vector graphics (SVG) rather than bitmaps (GIF or PNG).

18x16 GIF, PNG or SVG icon for the extension.

## Reserved Folders¶

In the early days, every extension baked it own bread when it came to file locations of PHP classes, public web resources and templates.

With the rise of Extbase, a generally accepted structure for file locations inside extensions has been established. If extension authors stick to this, the system helps in various ways. For instance, if putting PHP classes into the Classes/ folder and naming classes accordingly, the system will be able to autoload these without further action from the developer.

Extension kickstarters like the Extension Builder extension will create the correct structure for you.

It is described below:

Classes
Contains all PHP classes. One class per file. Should have sub folders like Controller/, Domain/, Service/ or View/. For more details on class file namings an PHP namespaces, see chapter namespaces.
Classes/Controller
Contains MVC Controller classes.
Classes/Domain/Model
Contains MVC Domain model classes.
Classes/Domain/Repository
Contains data repository classes.
Classes/ViewHelpers
Helper classes used in (Fluid) views.
Configuration
General configuration folder. Some of the sub directories in here like TCA and Backend have special meaning and files in there are automatically included during TYPO3 bootstrap.
Configuration/Backend/
Contains backend routing configurations. See files description of Routes.php and AjaxRoutes.php above.
Configuration/TCA
One file per database table, using the name of the table for the file, plus “.php”. Only for new tables.
Configuration/TCA/Overrides
For extending existing tables. General advice: One file per database table, using the name of the table for the file, plus “.php”. For more informations, see chapter Extending the TCA Array.
Configuration/TSconfig/Page
Page TSconfig, see chapter ‘Page TSconfig’ in the TSconfig Reference. Files should have the file extension .tsconfig.
Configuration/TSconfig/User
User TSconfig, see chapter ‘User TSconfig’ in the TSconfig Reference. Files should have the file extension .tsconfig.
Configuration/TypoScript
TypoScript static setup (setup.typoscript) and constants (constants.typoscript). Use subfolders if you have several static templates.
Documentation
Contains the extension documentation in ReStructuredText (ReST, .rst) format. Read more on the topic in chapter extension documentation. Documentation/ and its subfolders may contain several ReST files, images and other resources.
Documentation/Index.rst
This file contains the cover page of the extension manual in ReST format. The name or format of the file may not be changed. You may include other ReST files as you like. See the “Extension Template” on docs.typo3.org for more information about structure and syntax of extension manuals.
Resources
Contains the subfolders Public/ and Private/, which contain resources, possibly in further subfolders, e.g. Templates/, Css/, Language/, Images/ or JavaScript/. This is also the directory for non–TYPO3 files supplied with the extension. TYPO3 is licensed under GPL version 2 or any later version. Any non–TYPO3 code must be compatible with GPL version 2 or any later version.
Resources/Private/Language
XLIFF files for localized labels.
Resources/Private/Layouts
Main layouts for (Fluid) views.
Resources/Private/Partials
Partial templates for repetitive use.
Resources/Private/Templates
One template per action, stored in a folder named after each Controller.
Resources/Public/Css
Any CSS file used by the extension.
Resources/Public/Images
Any images used by the extension.
Resources/Public/JavaScript
Any JS file used by the extension.
Tests/Unit
Contains unit tests and fixtures.
Tests/Functional
Contains functional tests and fixtures.