To get the User resource for the authenticated user, use the self related link (href: "/self") of the root REST resource:
[Request]
> curl -k -u dlewis:novell https://amethyst.provo.novell.com:8443/rest/self
[Response]
{
"id":20,
"title":"David Lewis",
"name":"dlewis",
"description":{"text":"","format":2,"format_str":"text"},
"creation":{
"principal":{"id":20,"href":"/users/20"},
"date":"2016-01-18T21:14:18Z"
},
"modification":{
"principal":{"id":20,"href":"/users/20"},
"date":"2016-01-18T22:43:25Z"
},
"disabled":false,
"reserved":false,
"person":true,
"organization":"",
"phone":"",
"locale":{"country":"US","language":"en"},
"workspace":{"id":43,"href":"/workspaces/43"},
"href":"/self",
"links":[{
"rel":"shares_with",
"href":"/shares/with_user/20"
},{
"rel":"shares_by",
"href":"/shares/by_user/20"
},{
"rel":"password",
"href":"/users/20/password"
},{
"rel":"roots",
"href":"/self/roots"
},{
"rel":"my_files",
"href":"/self/my_files"
},{
"rel":"net_folders",
"href":"/self/net_folders"
},{
"rel":"shared_with_me",
"href":"/self/shared_with_me"
},{
"rel":"shared_by_me",
"href":"/self/shared_by_me"
},{
"rel":"public_shares",
"href":"/self/public_shares"
}],
"permalink":"...",
"email":"dlewis@novell.com",
"first_name":"David",
"middle_name":"",
"last_name":"Lewis",
"time_zone":"America/Boise",
"disk_quota":0,
"disk_space_used":0,
"disk_space_quota":104857600,
"hidden_files_folder":{"id":78,"href":"/folders/78"},
"mobile_app_config":{...},
"desktop_app_config":{...}
}