Good notes posted by rxcfcRSS feed
Imagine the following case. You have two landing pages, one generic one, and an account specific one. The urls are as follows:
map.landing 'landing', :controller => 'landing', :action => 'index' map.account_landing 'accounts/:account_id/landing', :controller => 'landing', :action => 'index'
Now imagine you want a path to the landing page, using the most specific route possible. If you have an account_id, use it, if not, skip it.
You could do
url_for(:controller => 'landing', :action => 'index', :account_id => current_account)
If current_account is set you’ll get “/accounts/:account_id/landing” if not, you’ll get “/landing”. However, that just looks ugly.
Enter :use_route => nil.
landing_path(:account_id => nil) # => '/landing' landing_path(:account_id => 1) # => '/landing?account_id=1' landing_path(:account_id => nil, :use_route => nil) # => '/landing' landing_path(:account_id => 1, :use_route => nil) # => '/accounts/1/landing'
Setting :use_route to nil, is equivalent to the earlier #url_for example.
According to the docs in form_options_helper.rb
:prompt - set to true or a prompt string. When the select element doesn’t have a value yet, this prepends an option with a generic prompt – “Please select” – or the given prompt string.
The main difference is that if the select already has a value, then :prompt will not show whereas the :include_blank always will.