before_save, strip a string

I'm trying to strip the whitespaces of the variable Username in my User Model.

I'm using

before_save do
  self.username.strip!
end

but it doesn't seem to work, am i missing something ?

You'd rather update the setter instead of polluting your model with callbacks:

def username=(value)
  self[:username] = value.to_s.strip
end

Btw, I prefer squish