To check unique name of user or resource, use command core/check_unique:
svc=core/check_unique¶ms={"type":<text>, "value":<text>}
| Name | Description | 
|---|---|
| type | item type (user, avl_resource) | 
| value | item name | 
{"result":0} /* if unique */
{"result":1} /* if exist */
  |