I have 2 local app "A" and "B". I want that the application "A" call the application "B" and "B" send a response to "A" with a file.
Url scheme is a good solution to call Application "B" but it's a bad solution to send files to "A".
How do I send a file from one application to another without url scheme and without external server ?
I've used a combination of custom URL schemes and a UIPasteboard. I recently posted a full tutorial at http://enharmonichq.com/sharing-data-locally-between-ios-apps/.
Other than URL option, you have an best option to use iOS keychain. See this article.
There are couple of other options mentioned here.
Another option is to use iCloud APIs.
One more, copy-paste data between Apps using UIPasteboard.
BTW what's the problem with URL solution? Apple suggest you to use URL to share data between different Apps.