My question is, Are the only REST methods GET POST PUT DELETE or can we have a method name like getUserFullName in REST ?
these are REST verbs, the common REST methods are:
index (get) show (get) new (get) create (post) edit (get) update (put) destroy (delete)
those you'll use in most cases. but you can still use as many other methods as you want. you should only think if it's really necessary in a given case.
think you have a user controller. index will show a list of all users show will show a single users detailed data new will show a form to enter new users create will create user based on the posted new form edit will get the edit form for an existing user update will update an existing user (from submitted edit form) destroy will delete an user
but you may want to export a csv list of selected users or import them from a vcard file or whatever, you cann still write an action like export_csv or import_vcard