You could use CloudKit. Following a snippet in Swift (ignoring errors):
let container = CKContainer.defaultContainer()
container.fetchUserRecordIDWithCompletionHandler(
{
(recordID, error) in
container.requestApplicationPermission(
.PermissionUserDiscoverability,
{
(status, error2) in
if (status == CKApplicationPermissionStatus.Granted)
{
container.discoverUserInfoWithUserRecordID(
recordID,
completionHandler:
{
(info, error3) in
println("\(info.firstName) \(info.lastName)")
}
)
}
}
)
}
)
The above code was based on the code at http://www.snip2code.com/Snippet/109633/CloudKit-User-Info
to save folks time. in swift4:
let container = CKContainer.default()
container.fetchUserRecordID(
completionHandler: {
(recordID, error) in
guard let recordID = recordID else {
return
}
container.requestApplicationPermission(
.userDiscoverability,
completionHandler: {
(status, error2) in
if (status == CKContainer_Application_PermissionStatus.granted)
{
if #available(iOS 10.0, *) {
container.discoverUserIdentity(withUserRecordID:
recordID,
completionHandler:
{
(info, error3) in
guard let info = info else {
return
}
print("\(info.firstName) \(info.lastName)")
}
)
}
}
}
)
}
)
however: CKUserIdentity no longer exposes either first or last name
So this answer no longer works.