+ # return_to param's format is 'remote,return_to_url'. This comes from login()
+ # encoding the remote=zbbbb parameter passed by a client asking for a salted
+ # token.
+ remote, return_to_url = params[:return_to].split(',', 2)
+ if remote !~ /^[0-9a-z]{5}$/ && remote != ""
+ return send_error 'Invalid remote cluster id', status: 400
+ end
+ remote = nil if remote == ''
+ return send_api_token_to(return_to_url, user, remote)