And once we receive the file, we should upload it directly to the user private file area

For iOs:

We need to specify with type of files supports the app

https://developer.apple.com/library/ios/documentation/FileManagement/Conceptual/DocumentInteraction_TopicsForIOS/Articles/RegisteringtheFileTypesYourAppSupports.html#//apple_ref/doc/uid/TP40010411-SW1

It wasn't possible to do that in Phonegap:
https://groups.google.com/forum/#!topic/phonegap/_ws_dSzyCV4

But starting Phonegap Build 3.1 it's possible:

https://github.com/phonegap/build/issues/213#issuecomment-31330060

See:
http://phonegap.com/blog/2014/01/30/customizing-your-android-manifest-and-ios-property-list-on-phonegap-build/

An the example for XML files:

<gap:config-file platform="ios" parent="CFBundleDocumentTypes">
<array>
<dict>
<key>CFBundleTypeName</key>
<string>XML File</string>
<key>CFBundleTypeRole</key>
<string>Editor</string>
<key>LSItemContentTypes</key>
<array>
<string>public.xml</string>
</array>
</dict>
</array>
</gap:config-file>

For Android:

Same as above, as custom preferences in Android Manifest
http://docs.build.phonegap.com/en_US/3.3.0/configuring_config_file_element.md.html#Config%20File%20Elements

Example for youtube:
http://stackoverflow.com/questions/525063/android-respond-to-url-in-intent

We need the WebIntent plugin, that currently we are using