How do I build the node title from field values when saving the node? I have a content type (supertest) with the Category and Section fields, which are taxonomy term references. Every user has a Display name field.
I need to update the node titles when saving the nodes using [category] - [section]: [author.display_name] as format.
I've tried to add a rule, Display message action (just to test) on Before content save event, but it doesn't work. I can't figure out how to use the category field value to set the node title.
How can I make rules to change the node title?
Could be a job for Automatic Entity Label. Actually I'm using it that way – in production (though it has no stable release yet it works just fine).


  "Automatic Entity Label" is a small and efficient module that allows
  hiding of entity label fields. To prevent empty labels it can be
  configured to generate the label automatically by a given pattern.


You can define tokens from which the title will be built. An you can optionally set the title field to be always hidden on the node form. I'd also recommend to make the fields mandatory (required) that you use to build the title.