[TYPO3-dev] Clearing cHash-specific cache

[Bernhard Kraft]

Michael Scharkow wrote:
> Hi guys,
> 
> while working on a FE-plugin using cHash for caching, I need to
> selectively delete a cache for a given cHash (or piVar-combination if
> you will):
> 
> I am in edit mode for a specific record, with some piVars indicating the
> mode and the record, of course, and *after* successfully modifying the
> record, the cache should be cleared for this cHash, so that I get to see
> the updated page in single view.
> 
> I could, of course, use
> 
> tslib_fe::clearPageCacheContent_pidList($TSFE->id);

AFAIK the cHash is very hard to generate if you want to clear the cHash from
a different page than you are currently on (TSConfig is taken into account for
cHash)


Kasper made a possibilty to "register" a specific value (reg1 AND reg2) for each page
which get's stored in the cache_pages table.

You do that by setting the appropriate "register/object property" from within you extension
which renders the single view of a specific record UID for example (in my case):

$GLOBALS['TSFE']->page_cache_reg1 = $this->singleViewUid;


If the page then get's stored completly in cache (because you don't have a USER_INT - with those
it wouldn't make much sense) the  value of this register will get stored in the reg1 and reg2
fields of the cache_pages table.

If you then would like to clear the cache for this page with the specific reg1/reg2 value you can
just do that by exec_DELETEquery as there is currently no method for clearing cache pages with
special reg1/reg2 values --- this would of course had to get added to the core API methods.


greets,
Bernhard