High CPU cost in app.php

[MorrisJobke]

The E2EE app registers an event listener for the "user deleted" hook. For this it needs the KeyStorage which is initialized in the register method. The constructor of the KeyStorage calls the method checkFolderStructure() which itself fetches the app data folder / and this operation is quite expensive - in our case it adds 170 ms to the whole request.

We should try to avoid such costly requests to each request and untangle the hooks a bit more. Hook registration should be super lightweight.

@schiessle Where is this checkFolderStructure() really needed? Can we move this somewhere else so that it is not executed on every request?

cc @nickvergessen @rullzer

[tobiasKaminsky]

Is this fixed?

[nickvergessen]

#97 removed like 20% of the total load, I guess there is more we could optimize, but not sure because i didnt install this app yet

[MorrisJobke]

Most of this is fixed in #97