Hook programming

Using TYPO3 Hooks

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For extension programmers.

Hooks are places in TYPO3 code where registered user-defined functions, so called callbacks, are called..

Usage of a hook:

1. Either the hook already exists in the core of TYPO3 and you can just register a callback.
2. Or it doesn't exist:
   • Thus you should identify its position in the code and insert it so the hook can call your code.
   • Then, as stated in 1., you register your callback.
   • In order to have a hook become permanent, you'll have to justify its necessity and ask for its inclusion into the official TYPO3 source code.

Hook references

• In TYPO3 Core Engine, a way too short hook description
  • http://typo3.org/documentation/document-library/core-documentation/doc_core_api/current/view/3/4/
• The extension dmc_hooklist (downloadable in TER) can show you a list of most of the hooks available.
• http://typo3.org/documentation/article/how-to-use-existing-hooks-in-your-own-extension/ How to use

Registered hooks in your installation

You will find all registered core hooks in $TYPO3_CONF_VARS['SC_OPTIONS'] (check the backend module Admin tools->Configuration for that).

You will find all registered hooks for extensions you will find in $TYPO3_CONF_VARS['EXTCONF'][ extension_key ][ sub_key ]