Consider storing in DocumentDirectory instead of CachesDirectory

[3lvis]

CachesDirectory is great because it leaves a small footprint on the devices but it really gives a worst experience when your phone is running out of available disk space since the Caches folder is cleared over and over again.

[3lvis]

A good option would be to store the data in the Documents directory but flaging the file as "do not back up".

https://developer.apple.com/icloud/documentation/data-storage/index.html