Developer’s Guide¶

Hooks¶

There are two hooks that can be used to manipulate the Data Structure produced by dataquery. They are similar but one is called before the structure is stored into cache, and the second one is called every time (i.e. either when the structure was freshly generated or when it was read from cache).

postProcessDataStructure

Called every time

postProcessDataStructureBeforeCache

Called when a structure has been newly generated and is about to be stored into cache (note that this hook is called also if the structure is not written to cache)

Both hooks receive as arguments the full Data Structure as well as a back-reference to the calling \Tesseract\Dataquery\Component\DataProvider object. They are expected to return a complete Data Structure even if they did not perform any change.

Skeleton code for both hooks can be found in Classes/Sample/DataQueryHook.php.

Another hook is available for manipulating the tables and fields information:

postProcessFieldInformation

This hook is inside \Tesseract\Dataquery\Component\DataProvider::getTablesAndFields(), a method which is called when “dataquery” provides Data Consumers with a list of available tables and fields while working within the TYPO3 backend (this is how, for example, “templatedisplay” knows which fields to map). This hook can be used when the data structure has been modified by one of the above hooks and such changes need to be known in the backend too. This is generally the case when the hooks change the tables and fields structure, so that these changed elements can be mapped properly.

Finally a hook can be used during cache hash calculation, for manipulating the parameters used to calculate the hash:

processCacheHashParameters

This hook is called inside \Tesseract\Dataquery\Component\DataProvider::calculateCacheHash(). It receives as arguments the current cache parameters (an associative array) and a back-reference to the calling object (an instance of \Tesseract\Dataquery\Component\DataProvider). It is expected to return the full array of cache parameters, whether it modified them or not. Classes using this hook must implement interface \Tesseract\Dataquery\Cache\CacheParametersProcessorInterface.