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TYPO3 Hook programming

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For extension programmers.

Hooks are a concept that allows a user defined function to be called at some specific point during TYPO3 execution.

Usage of a hook :

1. Either the hook already exists in the core of typo3 and you can insert a callback to your function into it.
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 custom function for callback.
   • In order to have a hook become permanent, you'll have to justify its necessity and ask for its inclusion into the Typo3 official source code.

Hook references

• In TYPO3 Core Engine, a much 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.