Downloading files and save it to a hidden folder on iPhone

Question

can some give me a good resource for the iphone filesystem? Basically I want to know:

1. Where can I save my downloaded files into which folders? And which are not allowed?
2. Which of these folders are hidden? (which won't be backup extracted) These files should stay on the device.

Want I'm trying to do is this: The user can download some videos from our server and watch it using our app. So I have to download the videos and save it somewhere on the iPhone, but I don't know exactly where to save these files so it won't be backup extracted.

First I tried ~/Documents folder, but the files in there will be extracted, so not an option for me.
Second I tried the ~/tmp folder. This folder seems to be working for me, because it wasn't extracted, but I don't know if this folder is always present? For how long will it persist? Because its called temp, will it be cleaned after some time/event?

If someone has information for me, I would really appreciate it.

Thanks in advice,
Buju

Answer 1

You might want to use <Application_Home>/Library/Caches.

From the apple docs @ https://developer.apple.com/iphone/prerelease/library/documentation/iPhone/Conceptual/iPhoneOSProgrammingGuide/RuntimeEnvironment/RuntimeEnvironment.html#//apple_ref/doc/uid/TP40007072-CH2-SW12

Use this directory to write any application-specific support files that you want to persist between launches of the application. Your application is generally responsible for adding and removing these files. However, iTunes removes these files during a full restore of the device so you should be able to recreate them as needed.

Answer 2

You need to read this:

Creating Paths and Locating Directories

All of it. Carefully.