Is it possible to upload files in an opensocial app to a remote appserver?
I think of a scenario using gadgets.io.makeRequest with the method set to gadgets.io.MethodType.POST and pass a file input to the gadgets.io.RequestParameters.POST_DATA.
With the current version of the spec, 1.1, it is not possible. Depending upon which container you are using though there maybe some vendor specific functionality which provides this functionality.