iCloud in OS X Implementation - which protocol does it use?

Question

In Mountain Lion, iCloud is "integrated" in every program. So when i open or save a document i have an iCloud option available.

But where are the documents? Are they local and get syned every now and then, or is it WebDAV or just http?

The documents load very fast, and there seems to be no delay.

Answer 1

iCloud documents are cached locally in ~/Library/Mobile Documents (~ represents your home folder).

They're synchronized via HTTPS (even when the application is closed) and the files (some of them, at least), are stored on Amazon S3.

When opening, editing and saving a TextEdit document from iCloud, these requests are made :

• POST request to https://p**-ubiquity.icloud.com/ub/*********/rwsync/********…
• POST request to https://p**-content.icloud.com/*********/authorizePut
• PUT request to Amazon S3
• POST request to https://p**-content.icloud.com/*********/putComplete
• POST request to https://p**-ubiquity.icloud.com/ub/*********/rwsync/********…
• POST request to https://p**-ubiquity.icloud.com/ub/*********/rosync/********…

Answer 2

Not sure if it's the same in Mountain Lion, but in Lion, iCloud documents are stored in ~/Library/Mobile Documents.

Answer 3

For clarity, existing answers state that the documents are stored at location X - whilst both are correct, please ensure you understand that they are merely cached in those locations, and if the iCloud synchronisation process detects a more up to date version in the cloud, then it will have to get it from there. In addition, for speed iCloud transfers META properties about the files it know about per application before loading content, which enables it to more speedily show you what is available.