[TYPO3-content-rendering] Re: apache error messages flooded with "no_cache ..." entries

[Florian Schwaiger]

Ok, so far I have found out what is triggering this. If someone encounters similar messages, this is the cause.

We implement a json API that can be called through Android and iPhone apps, their urls are accessible vie RealUrl. As there are some parameters within the url path, that change the output of the API, caching has to be adjusted. Because of the way RealUrl works, with only GET calls, the corresponding chash value is never put into the RealUrl cache table for the corresponding URL. In the beginning of our service, I did not notice that without automatic appending any chash values from RealUrl cache, the additional parameters are simply ignored. That resulted in weird behavior when wrong content was delivered and is indeed covered here: http://typo3.org/documentation/article/the-mysteries-of-chash

After reading the linked article, I added the problematic parameters to cHashRequiredParameters which now triggers all these "error" messages. Curiously only when requesting the urls via a REST toolkit, not via the browser.

The solution will surely be to generate and store chash values for known parameters preemptively. The article also describes some way to calculate them flexibly, but the code shown is way deprecated. I am sure that by generating links to the API calls with any LinkViewHelper would also trigger insertion of chash values into RealUrl cache.