ruby - Rails: replacing try with the Null Object Pattern -

in of applications, have current_user method. avoid exceptions in cases current_user.name current_user nil, rails provides try method. problem need remember use try wherever current_user might nil.

i want use null object pattern remove additional overhead.

class nulluser   def method_missing(method_name, *args)     nil   end end  def current_user   return nulluser.new unless usersession.find   @current_user ||= usersession.find.user end 

this can replace try in cases:

current_user.try(:first_name)     #=> nil current_user.first_name           #=> nil 

but fails further chaining:

current_user.profiles.first.name    #=> undefined method... 

---

i tried return null object:

class nulluser   def method_missing(method_name, *args)     self.class.new   end end  current_user.try { |u| u.profiles.first.name }  #=> nil current_user.profiles.first.name                #=> nil 

but fail in other cases:

current_user.is_admin?            #=>  #<nulluser:0x96f4e98> 

is there possible solution problem or have live try?

i stick nulluser change name guestuser make things clearer. additionally should stub important method user class, e.g.

class guestuser   def method_missing(method_name, *args)     nil   end    def is_admin?     false   end    # maybe fields:   def name     "guest"   end    # ... end