I'm new to Vault and how can I get all users who connected with server currently. thank you for your help
Sorry, but there are no APIs for this.
If you have Vault Workgroup or Vault Professional, it is possible to determine which users have licenses out by parsing the vlog. I believe a number of folks have done this with varying levels of success.
-Dave
I'm not sure what you mean by "checked out the folder". Folders do not have a reservation model like files and items. If two people try to edit folder properties at the same time, the last edit wins. If you want to know who created a folder, there is the "Created By" property.
If you really mean who checked out a specific file, files have a "Checked Out By" property.
-Dave