RoR: Creating/Updating: Showing validation errors while preserving previous values

I have a basic model in which i have specified some of the fields to validate the presence of. in the create action in the controller i do the standard:

@obj = SomeObject.new(params[:some_obj])

if @obj.save
  flash[:notice] = "ok"
  redirect...
else
  flash[:error] = @obj.errors.full_messages.collect { |msg| msg + "<br/>" }
  redirect to new form
end

however when i redirect to the new form, the errors show, but the fields are empty. is there a way to repopulate the fields with the entered values so the errors can be corrected easily?

From stackoverflow Jason Miesionczek

• You render :action => :new rather than redirecting.

  Ian Terrell : The reason behind this is so that you keep the object in memory rather than creating a new object; the redirect starts an entirely new request.

  James A. Rosen : The downside is that the form for creating a SomeObject now has two URLs: /some_objects/new # for the first form /some_objects # after a failed POST Not much can be done about it, though.

  Ryan Bigg : Good points Ian & Gauis
  From Ryan Bigg

• Capture @obj in the flash hash as well, and then check for it in the new action.

  @obj = SomeObject.new(params[:some_obj])
  
  if @obj.save
    flash[:notice] = "ok"
    # success
  else
    flash[:error] = @obj.errors.full_messages.collect { |msg| msg + "<br/>" }
    flash[:obj] = @obj
    # redirect to new form
  end
  

  In new:

  @obj = flash[:obj] || MyClass.new
  

  From nertzy