Hi.. I use uibuilder for ui. How do I add login and registration to ui?
You need to build something for yourself at the moment I'm afraid.
uibuilder provides a middleware capability for both the ExpressJS web server and for the websocket connection.
You can use those to check for the presence of a security token/cookie and if not present or not valid, redirect the client browser to a separate login page.
The login page can also be a uibuilder page so take the info from the user and submit it as a form (and check it in the Express middleware) or send it with uibuilder.send() (and check it using a Node-RED flow). The result of the check should either deliver a JWT token or a secure cookie that you than then check on future calls.
Note that since uibuilder generally uses websockets (socket.io) to communicate, you need to take care that you include security data from the client back to the server in any messages you send - then you need to have a flow that checks to see if the users credentials & session are still valid.
I know this all seems a bit complex and I've not had a chance to sit down and create a security example as yet unfortunately.