Question

Is there a built in method similar to update_attributes that will ignore invalid keys in the hash passed in as parameter? If not, what’s the best way to deal with the situation where you are sent a hash which may or may not include valid keys?

Answer 1

I’m not aware of anything that accomplishes this out of the box in Rails. I’m also not aware of a simple way to determine in general what a model’s “defined attributes” are—since a model may have overridden setters, virtual attributes, etc. Whenever I’ve needed this functionality, I’ve just explicitly defined a list of acceptable symbols in the class, something like this:

class Foo < ActiveRecord::Base
  def defined_attributes
    [ :a, :b, :c ]
  end
end

…and then used that later in some kind of filtering step:

  attrs = { :a => 1, :z => 0 }
  foo.update_attributes(attrs.slice(*foo.defined_attributes))